Retatrutide

1. Studied for

   Receptor pharmacology and discovery

   The discovery paper describes a single peptide that switches on three different hormone receptors at the same time: the glucagon receptor, the GIP receptor and the GLP-1 receptor. In the authors' own words, in cultured cells it 'shows balanced GCGR and GLP-1R activity but more GIPR activity'. In obese mice the compound reduced body weight and improved blood-sugar control, and the authors attributed that weight loss to two arms working together, writing that 'Body weight loss was augmented by the addition of GCGR-mediated increases in energy expenditure to GIPR- and GLP-1R-driven calorie intake reduction'. In an accompanying first-in-human study, a reduction in body weight was still measurable six weeks after one single amount was given. in cultured cells, plus obese mice, plus a first-in-human phase 1 study of single ascending amounts Preclinical strong Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere. Open for the full finding and the paper it came from.

   In the literature

   Receptor pharmacology and discovery

   The discovery paper describes a single peptide that switches on three different hormone receptors at the same time: the glucagon receptor, the GIP receptor and the GLP-1 receptor. In the authors' own words, in cultured cells it 'shows balanced GCGR and GLP-1R activity but more GIPR activity'. In obese mice the compound reduced body weight and improved blood-sugar control, and the authors attributed that weight loss to two arms working together, writing that 'Body weight loss was augmented by the addition of GCGR-mediated increases in energy expenditure to GIPR- and GLP-1R-driven calorie intake reduction'. In an accompanying first-in-human study, a reduction in body weight was still measurable six weeks after one single amount was given.^{References 1}

   Modelin cultured cells, plus obese mice, plus a first-in-human phase 1 study of single ascending amounts

   Confidence: strong

   Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere.

   Source

   Coskun T, Urva S, Roell WC, et al. LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: from discovery to clinical proof of concept. Cell Metab. 2022;34(9):1234-1247.e9. doi:10.1016/j.cmet.2022.07.013. PMID 35985340

   PubMed 35985340

   How this citation was checked

   Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 35985340 returned first author Coskun T, Cell Metab, 2022 Sep 6, volume 34, issue 9, pages 1234-1247.e9, DOI 10.1016/j.cmet.2022.07.013, all four matching what is written. The full abstract was retrieved by efetch and read: both quoted phrases above are verbatim from it, and the second one is quoted rather than paraphrased because an earlier draft of the research file had claimed the opposite, that energy expenditure was not altered. That fabricated attribution stays deleted, and the only paper on this page reporting energy expenditure unchanged is the rodent study further down. The draft's original DOI (10.1016/j.cmet.2022.08.004) resolves to a different paper entirely and stays replaced. Day 43 is restated as six weeks for readability. Every milligram figure printed in that abstract is deliberately not reproduced.

2. Studied for

   How long it stays in the body, and the first blood-sugar results in people

   In a 12-week early human study in 72 adults whose blood sugar was persistently high, the compound cleared from the body slowly, with a terminal half-life of about 6 days. By week 12, average daily blood glucose fell significantly in the three highest groups compared with placebo (differences of -2.8, -3.1 and -2.9 mmol/L), long-term blood sugar as measured by HbA1c fell significantly in the same three groups (-1.4%, -1.6% and -1.2% versus placebo), and body weight fell in proportion to the amount given, reaching -8.96 kg versus placebo in the highest group. Digestive side effects were the most frequently reported adverse events. human, phase 1b randomized double-blind placebo-controlled trial of multiple ascending amounts, 72 participants given the compound, 12 weeks Preclinical strong Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere. Open for the full finding and the paper it came from.

   In the literature

   How long it stays in the body, and the first blood-sugar results in people

   In a 12-week early human study in 72 adults whose blood sugar was persistently high, the compound cleared from the body slowly, with a terminal half-life of about 6 days. By week 12, average daily blood glucose fell significantly in the three highest groups compared with placebo (differences of -2.8, -3.1 and -2.9 mmol/L), long-term blood sugar as measured by HbA1c fell significantly in the same three groups (-1.4%, -1.6% and -1.2% versus placebo), and body weight fell in proportion to the amount given, reaching -8.96 kg versus placebo in the highest group. Digestive side effects were the most frequently reported adverse events.^{References 2}

   Modelhuman, phase 1b randomized double-blind placebo-controlled trial of multiple ascending amounts, 72 participants given the compound, 12 weeks

   Confidence: strong

   Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere.

   Source

   Urva S, Coskun T, Loh MT, et al. LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist in people with type 2 diabetes: a phase 1b, multicentre, double-blind, placebo-controlled, randomised, multiple-ascending dose trial. Lancet. 2022;400(10366):1869-1881. doi:10.1016/S0140-6736(22)02033-5. PMID 36354040

   PubMed 36354040

   How this citation was checked

   Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 36354040 returned first author Urva S, Lancet, 2022 Nov 26, volume 400, issue 10366, pages 1869-1881, DOI 10.1016/S0140-6736(22)02033-5, all matching. The full abstract was retrieved by efetch; the 6-day half-life, the 72 participants, the three glucose differences, the three HbA1c differences, the -8.96 kg figure and the digestive-events statement were each read verbatim from it. The milligram labels attached to those groups in the source are not reproduced, and neither is the frequency the investigators said the half-life supports: a schedule is usage guidance, and this page carries none. Published figures keep the units their papers report; the store's US-units rule governs the figures this file chooses for itself, which is storage temperature.

3. Studied for

   Body weight over 48 weeks

   In a 48-week randomized trial in 338 adults carrying excess body weight, or excess weight plus a weight-related condition, average body weight fell in proportion to the amount given. Across the four ascending groups, average body weight at 48 weeks was down 8.7%, 17.1%, 22.8% and 24.2%, against 2.1% in the placebo group. At the trial's main 24-week checkpoint the corresponding figures were 7.2%, 12.9%, 17.3% and 17.5%, against 1.6% on placebo. The most common side effects were digestive, scaled with the amount given, and were mostly mild to moderate. The investigators also reported increases in heart rate that scaled with the amount given, which peaked at 24 weeks and declined after that. human, phase 2 randomized double-blind placebo-controlled trial, 338 participants, 48 weeks Preclinical strong Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere. Open for the full finding and the paper it came from.

   In the literature

   Body weight over 48 weeks

   In a 48-week randomized trial in 338 adults carrying excess body weight, or excess weight plus a weight-related condition, average body weight fell in proportion to the amount given. Across the four ascending groups, average body weight at 48 weeks was down 8.7%, 17.1%, 22.8% and 24.2%, against 2.1% in the placebo group. At the trial's main 24-week checkpoint the corresponding figures were 7.2%, 12.9%, 17.3% and 17.5%, against 1.6% on placebo. The most common side effects were digestive, scaled with the amount given, and were mostly mild to moderate. The investigators also reported increases in heart rate that scaled with the amount given, which peaked at 24 weeks and declined after that.^{References 3}

   Modelhuman, phase 2 randomized double-blind placebo-controlled trial, 338 participants, 48 weeks

   Confidence: strong

   Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere.

   Source

   Jastreboff AM, Kaplan LM, Frias JP, et al. Triple-hormone-receptor agonist retatrutide for obesity: a phase 2 trial. N Engl J Med. 2023;389(6):514-526. doi:10.1056/NEJMoa2301972. PMID 37366315

   PubMed 37366315

   How this citation was checked

   Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 37366315 returned first author Jastreboff AM, N Engl J Med, 2023 Aug 10, volume 389, issue 6, pages 514-526, DOI 10.1056/NEJMoa2301972, all matching. The full abstract was retrieved by efetch; the 338 participants, all four 24-week values and their placebo comparator, all four 48-week values and their placebo comparator, the side-effect characterisation and the heart-rate sentence were each read verbatim. The draft's unsourced superlative, about this being the largest weight reduction described for an investigational agent of its kind, appears nowhere in the source and stays removed. Milligram labels are not reproduced.

4. Studied for

   Blood sugar, measured against a compound already on the market

   A randomized trial in 281 adults whose blood sugar was persistently high (entry HbA1c 7.0 to 10.5%, BMI 25 to 50) compared this compound against both a placebo and dulaglutide, a single-receptor GLP-1 compound already on the market. At 24 weeks the average fall in HbA1c ranged from 0.43% in the lowest group to 2.02% in the highest, against 0.01% on placebo and 1.41% with the marketed comparator. At 36 weeks body weight fell in proportion to the amount given, from 3.19% in the lowest group to 16.94% in the highest, against 3.00% on placebo and 2.02% with the comparator. Mild-to-moderate digestive side effects were reported by 35% of the participants given the compound, against 13% on placebo. human, phase 2 randomized double-blind placebo- and active-controlled trial, 281 participants Preclinical strong Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere. Open for the full finding and the paper it came from.

   In the literature

   Blood sugar, measured against a compound already on the market

   A randomized trial in 281 adults whose blood sugar was persistently high (entry HbA1c 7.0 to 10.5%, BMI 25 to 50) compared this compound against both a placebo and dulaglutide, a single-receptor GLP-1 compound already on the market. At 24 weeks the average fall in HbA1c ranged from 0.43% in the lowest group to 2.02% in the highest, against 0.01% on placebo and 1.41% with the marketed comparator. At 36 weeks body weight fell in proportion to the amount given, from 3.19% in the lowest group to 16.94% in the highest, against 3.00% on placebo and 2.02% with the comparator. Mild-to-moderate digestive side effects were reported by 35% of the participants given the compound, against 13% on placebo.^{References 4}

   Modelhuman, phase 2 randomized double-blind placebo- and active-controlled trial, 281 participants

   Confidence: strong

   Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere.

   Source

   Rosenstock J, Frias J, Jastreboff AM, et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA. Lancet. 2023;402(10401):529-544. doi:10.1016/S0140-6736(23)01053-X. PMID 37385280

   PubMed 37385280

   How this citation was checked

   Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 37385280 returned first author Rosenstock J, Lancet, 2023 Aug 12, volume 402, issue 10401, pages 529-544, DOI 10.1016/S0140-6736(23)01053-X, all matching. The full abstract was retrieved by efetch; the entry criteria, the 281 randomized participants, the HbA1c range and both comparator values, the 36-week bodyweight range and both comparator values, and the 35% versus 13% digestive figures were each read verbatim. Two draft errors stay fixed: a claimed mean baseline HbA1c of 8.3% that is not in the source, which gives an entry range, and the collapse of two maxima at different timepoints (HbA1c at 24 weeks, bodyweight at 36 weeks) into one. The abstract's statement that no severe low-blood-sugar episodes and no deaths occurred is deliberately not reproduced: it is safety reassurance built from an absence of events, which this store does not print. This trial is the only head-to-head against a marketed compound anywhere in this record.

5. Studied for

   Fat in the liver

   In a randomized substudy of 98 participants who had at least 10% of the liver made up of fat, the amount of liver fat fell sharply and in proportion to the amount given. At 24 weeks, average liver fat was down 42.9%, 57.0%, 81.4% and 82.4% across the four ascending groups, against a 0.3% increase on placebo (every comparison against placebo at p<0.001). By 24 weeks, a normal liver-fat level (under 5%) had been reached by 27%, 52%, 79% and 86% of participants in those groups, against nobody on placebo. The investigators reported that the liver-fat reductions tracked significantly with changes in body weight, abdominal fat, and measures tied to insulin sensitivity and fat handling. human, phase 2a randomized double-blind placebo-controlled substudy, 98 participants Preclinical strong Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere. Open for the full finding and the paper it came from.

   In the literature

   Fat in the liver

   In a randomized substudy of 98 participants who had at least 10% of the liver made up of fat, the amount of liver fat fell sharply and in proportion to the amount given. At 24 weeks, average liver fat was down 42.9%, 57.0%, 81.4% and 82.4% across the four ascending groups, against a 0.3% increase on placebo (every comparison against placebo at p<0.001). By 24 weeks, a normal liver-fat level (under 5%) had been reached by 27%, 52%, 79% and 86% of participants in those groups, against nobody on placebo. The investigators reported that the liver-fat reductions tracked significantly with changes in body weight, abdominal fat, and measures tied to insulin sensitivity and fat handling.^{References 5}

   Modelhuman, phase 2a randomized double-blind placebo-controlled substudy, 98 participants

   Confidence: strong

   Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere.

   Source

   Sanyal AJ, Kaplan LM, Frias JP, et al. Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial. Nat Med. 2024;30(7):2037-2048. doi:10.1038/s41591-024-03018-2. PMID 38858523

   PubMed 38858523

   How this citation was checked

   Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 38858523 returned first author Sanyal AJ, Nat Med, 2024 Jul, volume 30, issue 7, pages 2037-2048, DOI 10.1038/s41591-024-03018-2, all matching. The full abstract was retrieved by efetch; the 98 participants, all nine percentages above and the relationship sentence were read verbatim. The draft's absence-of-signal sentence about liver safety through 48 weeks appears nowhere in the source and stays deleted: it is an absence-of-evidence safety claim, and this store does not print those. Abdominal fat appears here only as a correlate that moved with liver fat, never as a measured endpoint, and is not written as one anywhere on this page. Milligram labels are not reproduced.

6. Studied for

   Where the lost weight comes from

   A prespecified body-scan substudy of the phase 2 blood-sugar trial (189 participants enrolled to the substudy) used DXA body scanning to separate fat from lean tissue. Total fat mass at week 36 was down 4.9% in the lowest group, 15.2% and 26.1% in the middle groups and 23.2% in the highest, against 4.5% on placebo and 2.6% with the marketed comparator. The authors' own conclusion is the important part: the share of the weight lost that came from lean tissue was similar to what other weight-loss approaches produce. In plain terms, lean tissue came off roughly in proportion to total weight rather than being selectively spared. This is the correct primary reference for any body-composition question about this compound, and nothing in it supports the claim, common on the pages selling it, that lean tissue is spared. human, DXA body-composition substudy of a phase 2 randomized double-blind placebo- and active-controlled trial, 189 participants enrolled to the substudy Preclinical strong Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere. Open for the full finding and the paper it came from.

   In the literature

   Where the lost weight comes from

   A prespecified body-scan substudy of the phase 2 blood-sugar trial (189 participants enrolled to the substudy) used DXA body scanning to separate fat from lean tissue. Total fat mass at week 36 was down 4.9% in the lowest group, 15.2% and 26.1% in the middle groups and 23.2% in the highest, against 4.5% on placebo and 2.6% with the marketed comparator. The authors' own conclusion is the important part: the share of the weight lost that came from lean tissue was similar to what other weight-loss approaches produce. In plain terms, lean tissue came off roughly in proportion to total weight rather than being selectively spared. This is the correct primary reference for any body-composition question about this compound, and nothing in it supports the claim, common on the pages selling it, that lean tissue is spared.^{References 6}

   Modelhuman, DXA body-composition substudy of a phase 2 randomized double-blind placebo- and active-controlled trial, 189 participants enrolled to the substudy

   Confidence: strong

   Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere.

   Source

   Coskun T, Wu Q, Schloot NC, Haupt A, Milicevic Z, Khouli C, Harris C. Effects of retatrutide on body composition in people with type 2 diabetes: a substudy of a phase 2, double-blind, parallel-group, placebo-controlled, randomised trial. Lancet Diabetes Endocrinol. 2025;13(8):674-684. doi:10.1016/S2213-8587(25)00092-0. PMID 40609566

   PubMed 40609566

   How this citation was checked

   Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 40609566 returned first author Coskun T, Lancet Diabetes Endocrinol, 2025 Aug, volume 13, issue 8, pages 674-684, DOI 10.1016/S2213-8587(25)00092-0, all matching, and all seven author names match the source byline. The full abstract was retrieved by efetch; the 189 participants, all five fat-mass percentages and the authors' interpretation sentence were read verbatim. That sentence cannot render word for word on this store, because it contains a term on the banned list; it is quoted in full in this file's _render_edits so the wording can still be checked. Noted for honesty: the same paragraph frames the result as reassurance that lean loss is not disproportionate. This page reports the neutral factual reading, that lean tissue is not selectively spared, which is what the sentence supports and the opposite of what four sources in this market sell.

7. Studied for

   Phase 3 confirmatory trial (TRANSCEND-T2D-1)

   TRANSCEND-T2D-1 was a 40-week phase 3 randomized double-blind placebo-controlled trial at 48 sites in the USA, Mexico and India, in 537 adults whose blood sugar diet and exercise alone had not brought under control. Using the analysis the paper reports as its primary one, which counts every randomized participant on the regimen assigned to them whatever happened afterward, average HbA1c fell 1.69%, 1.86% and 1.94% across the three ascending groups, against 0.81% on placebo (every comparison p<0.0001). Average body weight fell 11.5%, 13.9% and 15.3%, against 2.6% on placebo. Discontinuations because of side effects were 2 to 5% in the groups given the compound and 0% on placebo. Two deaths occurred during the study, both in the lowest group, and the investigators reported both as unrelated to the study drug. human, phase 3 randomized double-blind placebo-controlled trial, 537 participants randomized, 40 weeks Preclinical strong Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere. Open for the full finding and the paper it came from.

   In the literature

   Phase 3 confirmatory trial (TRANSCEND-T2D-1)

   TRANSCEND-T2D-1 was a 40-week phase 3 randomized double-blind placebo-controlled trial at 48 sites in the USA, Mexico and India, in 537 adults whose blood sugar diet and exercise alone had not brought under control. Using the analysis the paper reports as its primary one, which counts every randomized participant on the regimen assigned to them whatever happened afterward, average HbA1c fell 1.69%, 1.86% and 1.94% across the three ascending groups, against 0.81% on placebo (every comparison p<0.0001). Average body weight fell 11.5%, 13.9% and 15.3%, against 2.6% on placebo. Discontinuations because of side effects were 2 to 5% in the groups given the compound and 0% on placebo. Two deaths occurred during the study, both in the lowest group, and the investigators reported both as unrelated to the study drug.^{References 7}

   Modelhuman, phase 3 randomized double-blind placebo-controlled trial, 537 participants randomized, 40 weeks

   Confidence: strong

   Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere.

   Source

   Bajaj HS, Welch M, Shah P, et al. Efficacy and safety of retatrutide, a GIP, GLP-1, and glucagon receptor agonist, in people with type 2 diabetes and inadequate glycaemic control with diet and exercise (TRANSCEND-T2D-1): a double-blind, randomised, phase 3 trial. Lancet. 2026;407(10546):2402-2413. doi:10.1016/S0140-6736(26)00967-0. PMID 42250575

   PubMed 42250575

   How this citation was checked

   Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 42250575 returned first author Bajaj HS, Lancet, 2026 Jun 13, volume 407, issue 10546, pages 2402-2413, DOI 10.1016/S0140-6736(26)00967-0, all matching. The full abstract was retrieved by efetch; the 40 weeks, the 48 sites in those three countries, the 537 randomized participants, all three HbA1c values and the placebo value, all three bodyweight values and the placebo value, the 2 to 5% versus 0% discontinuations and the two deaths reported as unrelated to study drug were each read verbatim, as was the paper's explicit naming of the analysis restated above. The draft's 'approximately 16.8%' bodyweight figure appears nowhere in this paper (it belongs to the sponsor's other analysis) and stays removed rather than reattributed, so no analysis switch hides inside a peer-reviewed citation. The abstract's no-severe-low-blood-sugar statement is not reproduced, for the same reason it is not reproduced two rows up.

8. Studied for

   Blood pressure and blood fats, pooled across trials

   A systematic review and meta-analysis of randomized controlled trials pooled the available human data and reported significant reductions in systolic blood pressure (6.79 mmHg lower, 95% CI 8.36 to 5.23 lower, p<0.0001) and diastolic blood pressure (2.46 mmHg lower, 95% CI 3.25 to 1.67 lower, p<0.0001). It also reported significant reductions in total cholesterol (21.88 mg/dL lower), LDL cholesterol (13.10 mg/dL lower) and triglycerides (40.90 mg/dL lower), and no meaningful change in HDL cholesterol (0.01 mg/dL, p=0.98). Worth knowing about the consistency of these pooled numbers: the blood-pressure results were highly consistent across the included trials, while the total-cholesterol result varied a great deal between them (I-squared 84%), so that figure is the softest of the set. human, systematic review and meta-analysis of randomized controlled trials Preclinical strong Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere. Open for the full finding and the paper it came from.

   In the literature

   Blood pressure and blood fats, pooled across trials

   A systematic review and meta-analysis of randomized controlled trials pooled the available human data and reported significant reductions in systolic blood pressure (6.79 mmHg lower, 95% CI 8.36 to 5.23 lower, p<0.0001) and diastolic blood pressure (2.46 mmHg lower, 95% CI 3.25 to 1.67 lower, p<0.0001). It also reported significant reductions in total cholesterol (21.88 mg/dL lower), LDL cholesterol (13.10 mg/dL lower) and triglycerides (40.90 mg/dL lower), and no meaningful change in HDL cholesterol (0.01 mg/dL, p=0.98). Worth knowing about the consistency of these pooled numbers: the blood-pressure results were highly consistent across the included trials, while the total-cholesterol result varied a great deal between them (I-squared 84%), so that figure is the softest of the set.^{References 8}

   Modelhuman, systematic review and meta-analysis of randomized controlled trials

   Confidence: strong

   Convergent results from more than one randomized controlled trial, or one large late-stage trial whose result is reproduced elsewhere in this record. On this compound that mostly means human data, which is unusual here. It still describes an investigational compound with no approved use anywhere.

   Source

   Simental-Mendia LE, Barragan-Zuniga LJ, Reyes-Avitia V. Effect of retatrutide, a novel triple receptor agonist, on blood pressure and lipid levels: a systematic review and meta-analysis of randomized controlled trials. High Blood Press Cardiovasc Prev. 2026; online ahead of print, published June 29. doi:10.1007/s40292-026-00812-6. PMID 42371360

   PubMed 42371360

   How this citation was checked

   Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 42371360 returned first author Simental-Mendia LE, High Blood Press Cardiovasc Prev, 2026 Jun 29, DOI 10.1007/s40292-026-00812-6, with NO volume, issue or page numbers assigned, which is why the citation says online ahead of print rather than giving fabricated volume and pages. The full abstract was retrieved by efetch; every weighted mean difference, confidence interval, p value and I-squared value above was read verbatim from it, including the 20%, 0%, 84%, 47% and 53% heterogeneity figures behind the consistency sentence. The HDL result is stated rather than omitted because it is the reason this page speaks only to LDL, total cholesterol and triglycerides and never to the lipid panel as a whole.

9. Studied for

   Rodent studies in excess weight and liver fat

   In obese mice with fat accumulation in the liver, the compound reduced body weight by 31% compared with animals not given it (p<0.0001), and that loss came from BOTH fat and lean tissue. Food and water intake dropped in the first days, while the rate at which the animals burned energy was NOT significantly changed. It markedly reduced a standard index of insulin resistance and reduced liver fat scoring, fatty acids, triglycerides and cholesterol content in the liver. In obese hamsters it shifted what the animals chose to eat, increasing plain chow and decreasing both the high-fat high-cholesterol food and the sugar water. Weight loss there again came from both fat and lean tissue, although lean tissue was no longer different from controls after five weeks. Liver triglyceride content fell by about half (p<0.01), but the microscopic liver damage scoring did not improve. RODENT rodent (diet-induced obese mice with fat accumulation in the liver, and diet-induced obese hamsters) Preclinical moderate A well-described result with several independent outcome measures, but from a single study, a single laboratory or a single animal model. Open for the full finding and the paper it came from.

   In the literature

   Rodent studies in excess weight and liver fat

   In obese mice with fat accumulation in the liver, the compound reduced body weight by 31% compared with animals not given it (p<0.0001), and that loss came from BOTH fat and lean tissue. Food and water intake dropped in the first days, while the rate at which the animals burned energy was NOT significantly changed. It markedly reduced a standard index of insulin resistance and reduced liver fat scoring, fatty acids, triglycerides and cholesterol content in the liver. In obese hamsters it shifted what the animals chose to eat, increasing plain chow and decreasing both the high-fat high-cholesterol food and the sugar water. Weight loss there again came from both fat and lean tissue, although lean tissue was no longer different from controls after five weeks. Liver triglyceride content fell by about half (p<0.01), but the microscopic liver damage scoring did not improve.^{References 9}

   Modelrodent (diet-induced obese mice with fat accumulation in the liver, and diet-induced obese hamsters)

   Confidence: moderate

   A well-described result with several independent outcome measures, but from a single study, a single laboratory or a single animal model.

   Source

   Briand F, Le Cudennec C, Grasset E, Breyner N, Bigot C, Dillard P, Sulpice T. Retatrutide shows multiple metabolic benefits in diet-induced obese MASH mouse and hamster models. Obesity (Silver Spring). 2026;34(Suppl 1):43-53. doi:10.1002/oby.70155. PMID 41741376

   PubMed 41741376

   How this citation was checked

   Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 41741376 returned first author Briand F, Obesity (Silver Spring), 2026 Jun, volume 34 Suppl 1, pages 43-53, DOI 10.1002/oby.70155, all matching, and all seven author names match the source byline. The full structured abstract was retrieved by efetch; the 31% reduction and its p value, 'both fat and lean mass', 'energy expenditure was not altered significantly', the food-preference shift, 'the lean mass was not different after 5 weeks', the 50% liver triglyceride reduction with p<0.01 and 'did not reduce histopathological scoring' were each read verbatim. The draft's phrasing 'adipose AND muscle tissue' stays corrected to fat and lean mass, which is what the paper says and a different compartment; that wording is load-bearing, because it is the basis for refusing the claim that lean tissue is spared. The bone-mineral-density sentence is not reproduced: an absence-of-change statement reads as safety reassurance on a commerce page. This paper is also one half of the energy-expenditure disagreement described in the open questions.

10. Studied for

    Learning and memory in a rodent model

    In male rats made insulin-deficient with streptozotocin, the compound lowered blood glucose but did not prevent the weight loss that comes with that model. In maze testing, the rats given the compound held their overall performance against animals in the same model that were not given it, and showed a limited, task-dependent easing of a short-term avoidance-memory deficit rather than a full return to normal across memory measures. This is protection from decline, not improvement. It came alongside a significant drop in a hippocampal inflammatory marker (TNF-alpha), a non-significant trend toward lower IL-1beta, and partial preservation of brain tissue structure in the cortex and hippocampus. In healthy rats given the compound alone, behavior did not improve beyond normal control levels. The authors explicitly noted that they did not establish whether the compound reached the brain directly. RODENT rodent (streptozotocin-induced insulin-deficient male Sprague-Dawley rats) Preclinical moderate A well-described result with several independent outcome measures, but from a single study, a single laboratory or a single animal model. Open for the full finding and the paper it came from.

    In the literature

    Learning and memory in a rodent model

    In male rats made insulin-deficient with streptozotocin, the compound lowered blood glucose but did not prevent the weight loss that comes with that model. In maze testing, the rats given the compound held their overall performance against animals in the same model that were not given it, and showed a limited, task-dependent easing of a short-term avoidance-memory deficit rather than a full return to normal across memory measures. This is protection from decline, not improvement. It came alongside a significant drop in a hippocampal inflammatory marker (TNF-alpha), a non-significant trend toward lower IL-1beta, and partial preservation of brain tissue structure in the cortex and hippocampus. In healthy rats given the compound alone, behavior did not improve beyond normal control levels. The authors explicitly noted that they did not establish whether the compound reached the brain directly.^{References 10}

    Modelrodent (streptozotocin-induced insulin-deficient male Sprague-Dawley rats)

    Confidence: moderate

    A well-described result with several independent outcome measures, but from a single study, a single laboratory or a single animal model.

    Source

    Keskin U, Altin E, Kara MK, et al. Effects of retatrutide on learning and memory in streptozotocin-induced male diabetic rats. Behav Brain Res. 2026;514:116343. doi:10.1016/j.bbr.2026.116343. PMID 42385950

    PubMed 42385950

    How this citation was checked

    Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 42385950 returned first author Keskin U, Behav Brain Res, 2026 Jul 1, volume 514, article 116343, DOI 10.1016/j.bbr.2026.116343, all matching. The full abstract was retrieved by efetch; the sentence describing preserved overall Morris Water Maze performance and a limited, task-dependent attenuation of short-term avoidance deficits rather than complete normalisation is verbatim in the source and is paraphrased here only because it carries a banned term (the full sentence is in _render_edits). Also read verbatim: the failure to prevent weight loss, the significant TNF-alpha reduction, the non-significant IL-1beta trend, the partial cytoarchitecture preservation, the no-improvement-beyond-control result in healthy animals and the authors' own caveat about central exposure. The draft's verb 'improved' stays corrected to the paper's 'preserved', which is a materially different claim. This row is kept rather than dropped because it is the only evidence on this page that speaks to a cognitive question at all, and what it says is that nothing improved.

11. Studied for

    Structure of the late-stage trial program (TRIUMPH)

    TRIUMPH is a program of four phase 3 multicenter randomized double-blind studies comparing weekly use of the compound against placebo, alongside diet and physical activity, in over 5,800 participants. It uses an unusual nested design: two of the studies are weight-management trials with two further protocols running inside them, a third is a weight-management trial in people who already carry a cardiovascular diagnosis, and a fourth is a standalone trial for one of those two further protocols. The main measure for weight management is percent change in body weight; the two nested protocols carry their own separate main measures, which the citation names. THIS PAPER REPORTS THE PLAN ONLY. It contains no results of any kind, which is why nothing on this page claims an outcome for anything the program is measuring. human, phase 3 registrational program; peer-reviewed design and rationale paper reporting no outcomes Preclinical preliminary A single study, an early mechanistic observation in isolated tissue, a paper that reports a trial's design and no outcomes at all, or a figure announced by the sponsor and not yet peer-reviewed. Open for the full finding and the paper it came from.

    In the literature

    Structure of the late-stage trial program (TRIUMPH)

    TRIUMPH is a program of four phase 3 multicenter randomized double-blind studies comparing weekly use of the compound against placebo, alongside diet and physical activity, in over 5,800 participants. It uses an unusual nested design: two of the studies are weight-management trials with two further protocols running inside them, a third is a weight-management trial in people who already carry a cardiovascular diagnosis, and a fourth is a standalone trial for one of those two further protocols. The main measure for weight management is percent change in body weight; the two nested protocols carry their own separate main measures, which the citation names. THIS PAPER REPORTS THE PLAN ONLY. It contains no results of any kind, which is why nothing on this page claims an outcome for anything the program is measuring.^{References 11}

    Modelhuman, phase 3 registrational program; peer-reviewed design and rationale paper reporting no outcomes

    Confidence: preliminary

    A single study, an early mechanistic observation in isolated tissue, a paper that reports a trial's design and no outcomes at all, or a figure announced by the sponsor and not yet peer-reviewed.

    Source

    Giblin K, Kaplan LM, Somers VK, et al. Retatrutide for the treatment of obesity, obstructive sleep apnea and knee osteoarthritis: rationale and design of the TRIUMPH registrational clinical trials. Diabetes Obes Metab. 2026;28(1):83-93. doi:10.1111/dom.70209. PMID 41090431

    PubMed 41090431

    How this citation was checked

    Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 41090431 returned first author Giblin K, Diabetes Obes Metab, 2026 Jan, volume 28, issue 1, pages 83-93, DOI 10.1111/dom.70209, all matching. The full abstract was retrieved by efetch; the four-trial structure, the over 5,800 participants, the three primary endpoints and the basket design were read verbatim. Two of those three endpoints are named only in the citation title and not in the finding above, under this store's rule that its own prose does not name a disease. CONFIDENCE CONVENTION, applied consistently: a paper that reports no outcomes is graded preliminary here whatever the journal or the size of the programme, because no result exists yet to support. The design and baseline paper further down gets the same grade for the same reason.

12. Studied for

    TRIUMPH-1 headline figures announced by the sponsor, not peer-reviewed

    SOURCING CAVEAT FIRST, because it governs everything that follows: these figures come from a company news release, not from a peer-reviewed publication, and a PubMed search run in the research pass found no TRIUMPH-1 outcomes paper indexed. TRIUMPH-1 is an 80-week phase 3 randomized double-blind placebo-controlled trial that randomized 2,339 participants carrying excess body weight, or excess weight plus a weight-related condition, and with normal blood sugar. Under the company's more favorable of two analyses, average body weight at 80 weeks was down 19.0%, 25.9% and 28.3% across the three ascending groups, against 2.2% on placebo. Under the more conservative analysis the same figures were 17.6%, 23.7% and 25.0%, against 3.9% on placebo. Both sets are given because the gap between them is exactly the kind of detail that gets dropped in retelling. A pre-specified extension to 104 weeks enrolled only people who had already completed 80 weeks and tolerated the amount assigned to them, so its figures come from a self-selected group and are not comparable to the main trial; they are not reproduced here. On side effects, the announcement reported nausea, diarrhea, constipation and vomiting rising with the amount given; a nerve-sensation side effect (dysesthesia) in 5.1%, 12.3% and 12.5% of the groups given the compound against 0.9% on placebo; and discontinuation because of side effects in 4.1%, 6.9% and 11.3% against 4.9% on placebo. None of this may be presented with the weight of the peer-reviewed trials above. human, phase 3 trial; company topline news release only, not peer-reviewed Preclinical preliminary A single study, an early mechanistic observation in isolated tissue, a paper that reports a trial's design and no outcomes at all, or a figure announced by the sponsor and not yet peer-reviewed. Open for the full finding and the paper it came from.

    In the literature

    TRIUMPH-1 headline figures announced by the sponsor, not peer-reviewed

    SOURCING CAVEAT FIRST, because it governs everything that follows: these figures come from a company news release, not from a peer-reviewed publication, and a PubMed search run in the research pass found no TRIUMPH-1 outcomes paper indexed. TRIUMPH-1 is an 80-week phase 3 randomized double-blind placebo-controlled trial that randomized 2,339 participants carrying excess body weight, or excess weight plus a weight-related condition, and with normal blood sugar. Under the company's more favorable of two analyses, average body weight at 80 weeks was down 19.0%, 25.9% and 28.3% across the three ascending groups, against 2.2% on placebo. Under the more conservative analysis the same figures were 17.6%, 23.7% and 25.0%, against 3.9% on placebo. Both sets are given because the gap between them is exactly the kind of detail that gets dropped in retelling. A pre-specified extension to 104 weeks enrolled only people who had already completed 80 weeks and tolerated the amount assigned to them, so its figures come from a self-selected group and are not comparable to the main trial; they are not reproduced here. On side effects, the announcement reported nausea, diarrhea, constipation and vomiting rising with the amount given; a nerve-sensation side effect (dysesthesia) in 5.1%, 12.3% and 12.5% of the groups given the compound against 0.9% on placebo; and discontinuation because of side effects in 4.1%, 6.9% and 11.3% against 4.9% on placebo. None of this may be presented with the weight of the peer-reviewed trials above.^{References 12}

    Modelhuman, phase 3 trial; company topline news release only, not peer-reviewed

    Confidence: preliminary

    A single study, an early mechanistic observation in isolated tissue, a paper that reports a trial's design and no outcomes at all, or a figure announced by the sponsor and not yet peer-reviewed.

    Source

    Eli Lilly and Company. Lilly's triple agonist, retatrutide, delivered powerful weight loss in pivotal Phase 3 obesity trial. News release, May 21, 2026 (TRIUMPH-1, NCT05929066).

    Source

    How this citation was checked

    Carried forward from research/clean/retatrutide.json, which fetched this release live in its own pass and read it in full (HTTP 200). The release confirms verbatim: the trial identity and registration, the 2,339 randomized participants, the three figures under each of the two analyses and their placebo comparators, the 104-week extension together with its enrolment restriction to completers with high baseline BMI, the four digestive event rates, the three dysesthesia rates against 0.9% on placebo and the three discontinuation rates against 4.9% on placebo. The release also states plainly that the compound is investigational and available only to people in the company's own clinical trials. TWO THINGS REMOVED: the knee-pain and sleep-measure figures, which rested on a companion investor release that could NOT be resolved on repeated live attempts (connection failed, HTTP 000), and which this release itself says would be reported separately; and the 104-week extension figure, kept out under this store's rule against a long-term weight-management claim while its self-selection caveat is carried forward in the finding. Milligram labels are not reproduced.

13. Studied for

    Kidney-function study, design and baseline only (TRANSCEND-CKD)

    TRANSCEND-CKD is a double-blind placebo-controlled phase 2b mechanism study in adults who have both excess body weight and reduced kidney filtration (25 to 75 mL/min/1.73 m2), with or without high blood sugar, randomized one-to-one against a matched placebo. Of 367 people screened, 146 were randomized. At entry, average age was 65.1 years, 45.2% were female, average weight was 101.1 kg, average BMI 35.7, average directly measured kidney filtration 49.3 mL/min/1.73 m2, and 37.7% had high blood sugar. The main question is the change in directly measured kidney filtration at 24 weeks, with MRI scanning of kidney blood flow and of fat around and inside the kidney as additional measures. THIS PAPER REPORTS THE PLAN AND THE STARTING CHARACTERISTICS ONLY. It contains no results, which is why this page makes no kidney claim of any kind. human, phase 2b mechanistic randomized double-blind placebo-controlled trial; design and baseline paper reporting no outcomes Preclinical preliminary A single study, an early mechanistic observation in isolated tissue, a paper that reports a trial's design and no outcomes at all, or a figure announced by the sponsor and not yet peer-reviewed. Open for the full finding and the paper it came from.

    In the literature

    Kidney-function study, design and baseline only (TRANSCEND-CKD)

    TRANSCEND-CKD is a double-blind placebo-controlled phase 2b mechanism study in adults who have both excess body weight and reduced kidney filtration (25 to 75 mL/min/1.73 m2), with or without high blood sugar, randomized one-to-one against a matched placebo. Of 367 people screened, 146 were randomized. At entry, average age was 65.1 years, 45.2% were female, average weight was 101.1 kg, average BMI 35.7, average directly measured kidney filtration 49.3 mL/min/1.73 m2, and 37.7% had high blood sugar. The main question is the change in directly measured kidney filtration at 24 weeks, with MRI scanning of kidney blood flow and of fat around and inside the kidney as additional measures. THIS PAPER REPORTS THE PLAN AND THE STARTING CHARACTERISTICS ONLY. It contains no results, which is why this page makes no kidney claim of any kind.^{References 13}

    Modelhuman, phase 2b mechanistic randomized double-blind placebo-controlled trial; design and baseline paper reporting no outcomes

    Confidence: preliminary

    A single study, an early mechanistic observation in isolated tissue, a paper that reports a trial's design and no outcomes at all, or a figure announced by the sponsor and not yet peer-reviewed.

    Source

    Heerspink HJL, van Raalte DH, Bjornstad P, et al. Rationale, design and baseline characteristics of the TRANSCEND-CKD trial of retatrutide in patients with chronic kidney disease. Nephrol Dial Transplant. 2026;41(6):1058-1068. doi:10.1093/ndt/gfaf230. PMID 41160422

    PubMed 41160422

    How this citation was checked

    Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 41160422 returned first author Heerspink HJL, Nephrol Dial Transplant, 2026 May 29, volume 41, issue 6, pages 1058-1068, DOI 10.1093/ndt/gfaf230, all matching. The full abstract was retrieved by efetch; the filtration entry range, the entry definition, the 367 screened and 146 randomized, and every baseline figure above were read verbatim, as were the primary objective and the MRI measures. Graded preliminary under the same convention as the design paper above, correcting an earlier draft that graded two structurally identical claim types differently. Maximum-amount figures in the source are not reproduced.

14. Studied for

    Isolated mouse heart tissue: a mechanism for the faster heartbeat

    Working with isolated, still-beating right atrial tissue from mice in an organ bath, researchers found the compound made the tissue beat faster, with the effect reaching statistical significance at low nanomolar concentrations and, at the higher concentration tested, coming close to the effect of a standard adrenaline-like stimulant. In separate electrically paced left atrial tissue from the same animals, the compound did NOT increase the force of contraction, though the adrenaline-like stimulant did. Blocking each of the three target receptors in turn showed that only the glucagon-receptor blocker significantly reduced the faster beating; the GLP-1 and GIP receptor blockers did not. The effect survived a beta-blocker but was blunted by an inhibitor of the PKA enzyme, and was amplified by a drug that stops cAMP being broken down. The authors concluded the compound speeds the beating rate in mouse right atria through the glucagon receptor, signalling via cAMP and PKA. They framed the study around the observation that this compound raised heart rate in human safety studies, and listed a direct action on the heart's pacemaker as one of three candidate explanations they set out to test. EX VIVO ex vivo isolated atrial tissue from adult CD1 mice, in an organ bath Preclinical preliminary A single study, an early mechanistic observation in isolated tissue, a paper that reports a trial's design and no outcomes at all, or a figure announced by the sponsor and not yet peer-reviewed. Open for the full finding and the paper it came from.

    In the literature

    Isolated mouse heart tissue: a mechanism for the faster heartbeat

    Working with isolated, still-beating right atrial tissue from mice in an organ bath, researchers found the compound made the tissue beat faster, with the effect reaching statistical significance at low nanomolar concentrations and, at the higher concentration tested, coming close to the effect of a standard adrenaline-like stimulant. In separate electrically paced left atrial tissue from the same animals, the compound did NOT increase the force of contraction, though the adrenaline-like stimulant did. Blocking each of the three target receptors in turn showed that only the glucagon-receptor blocker significantly reduced the faster beating; the GLP-1 and GIP receptor blockers did not. The effect survived a beta-blocker but was blunted by an inhibitor of the PKA enzyme, and was amplified by a drug that stops cAMP being broken down. The authors concluded the compound speeds the beating rate in mouse right atria through the glucagon receptor, signalling via cAMP and PKA. They framed the study around the observation that this compound raised heart rate in human safety studies, and listed a direct action on the heart's pacemaker as one of three candidate explanations they set out to test.^{References 14}

    Modelex vivo isolated atrial tissue from adult CD1 mice, in an organ bath

    Confidence: preliminary

    A single study, an early mechanistic observation in isolated tissue, a paper that reports a trial's design and no outcomes at all, or a figure announced by the sponsor and not yet peer-reviewed.

    Source

    Neumann J, Ahlrep U, Hofmann B, Gergs U. Contractile effects of retatrutide in isolated mouse atrial preparations. Naunyn Schmiedebergs Arch Pharmacol. 2025;398(12):17147-17160. doi:10.1007/s00210-025-04335-0. PMID 40464942

    PubMed 40464942

    How this citation was checked

    Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 40464942 returned first author Neumann J, Naunyn Schmiedebergs Arch Pharmacol, 2025 Dec, volume 398, issue 12, pages 17147-17160, DOI 10.1007/s00210-025-04335-0, all matching. The abstract was read by efetch, and because several details sit outside it the open-access full text (PMC12678479) was retrieved as well: the concentration at which the faster beating gained significance, the comparison with isoprenaline at the higher concentration, and the statement that only the glucagon-receptor blocker significantly reduced the effect while the GLP-1 and GIP receptor blockers did not, were each confirmed there. The numeric bath concentrations behind the qualitative wording above are recorded in the source file rather than printed here. TWO CORRECTIONS KEPT: the human-tissue result that was once attributed to this paper belongs to a separate publication, which has its own row below; and a sentence written in the dossier's own neutral voice, claiming this provides a mechanistic correlate for the heart-rate increases in trials, is replaced by the authors' own stated rationale, which lists that as one candidate explanation among three.

15. Studied for

    Isolated human heart tissue: force of contraction

    Working with small strips of right atrial tissue removed during open-heart surgery from adults with severe narrowing of the coronary arteries, researchers found that adding the compound to the organ bath in rising nanomolar concentrations increased the force of contraction, building over concentration and over time, and shortened the time the muscle took to relax. When an enzyme that breaks down cAMP was blocked first, the compound became both more potent and more effective at increasing contraction force. That increase in force was greatly reduced by blockers of the GLP-1, GIP and glucagon receptors, was not blocked by a beta-blocker, and was also reduced by a drug that blocks calcium release from internal stores, by a nerve-signal mimic and by an adenosine receptor agonist. The authors concluded the compound increases contraction force in human atrial tissue through the cAMP system acting via its own three receptors. IMPORTANT FRAMING: this is donated tissue in a dish, not a study in living people, and it says nothing about what happens in an intact body. EX VIVO ex vivo human right atrial tissue obtained at cardiac surgery, in an organ bath Preclinical preliminary A single study, an early mechanistic observation in isolated tissue, a paper that reports a trial's design and no outcomes at all, or a figure announced by the sponsor and not yet peer-reviewed. Open for the full finding and the paper it came from.

    In the literature

    Isolated human heart tissue: force of contraction

    Working with small strips of right atrial tissue removed during open-heart surgery from adults with severe narrowing of the coronary arteries, researchers found that adding the compound to the organ bath in rising nanomolar concentrations increased the force of contraction, building over concentration and over time, and shortened the time the muscle took to relax. When an enzyme that breaks down cAMP was blocked first, the compound became both more potent and more effective at increasing contraction force. That increase in force was greatly reduced by blockers of the GLP-1, GIP and glucagon receptors, was not blocked by a beta-blocker, and was also reduced by a drug that blocks calcium release from internal stores, by a nerve-signal mimic and by an adenosine receptor agonist. The authors concluded the compound increases contraction force in human atrial tissue through the cAMP system acting via its own three receptors. IMPORTANT FRAMING: this is donated tissue in a dish, not a study in living people, and it says nothing about what happens in an intact body.^{References 15}

    Modelex vivo human right atrial tissue obtained at cardiac surgery, in an organ bath

    Confidence: preliminary

    A single study, an early mechanistic observation in isolated tissue, a paper that reports a trial's design and no outcomes at all, or a figure announced by the sponsor and not yet peer-reviewed.

    Source

    Neumann J, Ahlrep U, Hofmann B, Gergs U. Inotropic effects of retatrutide in isolated human atrial preparations. Naunyn Schmiedebergs Arch Pharmacol. 2026;399(1):317-327. doi:10.1007/s00210-025-04421-3. PMID 40613938

    PubMed 40613938

    How this citation was checked

    Verification carried forward from research/clean/retatrutide.json, which re-resolved this citation in its own pass. PubMed esummary on PMID 40613938 returned first author Neumann J, Naunyn Schmiedebergs Arch Pharmacol, 2026 Jan, volume 399, issue 1, pages 317-327, DOI 10.1007/s00210-025-04421-3, all matching. NAMING AMBIGUITY, CARRIED FORWARD DELIBERATELY: the first author is Neumann, not Ahlrep; the sibling paper's in-text citation style is what produced the erroneous 'Ahlrep et al.' attribution in circulation. A SECOND DEFECT IN THE SOURCE PAPER, ALSO CARRIED FORWARD: its published abstract contains an apparent typographical slip, writing 'These positive inotropic effects of glucagon were diminished by...' in a paper whose subject is retatrutide, so this row is written from the open-access full text (PMC12894140) rather than from the abstract. The Results section there resolves it unambiguously for retatrutide, and also supplies the concentration at which the effect began and plateaued, the shortened relaxation time, the three antagonists, and the finding that with a beta-blocker and an alpha-blocker present beforehand the compound still roughly doubled contraction force. Numeric bath concentrations are described qualitatively above.

8 strong / 2 moderate / 5 preliminaryRated by how many independent labs and how many kinds of experiment found the same thing.