262 trials, 19 drugs: where retatrutide actually stands in the BMJ analysis
The BMJ network meta-analysis compares 19 drugs across 262 trials. For retatrutide, it gives no figure of its own, only a range shared across three drugs.
TL;DR: No standalone figure for retatrutide
Date: 8 July 2026, BMJ (PMID 42419792)
Scope: 262 randomised trials, 99,791 participants, 19 drugs, follow-up of 12 to 172 weeks.
The finding: The analysis gives no standalone figure for retatrutide. It groups it together with ecnoglutide and mazdutide as "emerging agents" and reports a range of 13.1 to 14.6 percent for these three combined, rated very low to low certainty.
By comparison: For tirzepatide it reports 14.9 percent, at moderate to high certainty, and likewise standalone figures for five other drugs.
Why this matters: This work does not let you conclude that retatrutide is stronger, nor that it is weaker. What it mainly tells you is how thin the current evidence base is.
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What this analysis does differently
Most figures circulating about retatrutide come from individual trials, each with its own population, its own duration and its own comparator group. The problem is not that these figures are wrong. The problem is what gets done with them.
Placing a figure from an 80-week trial next to a figure from another trial with a different duration and a different comparator group, and drawing a ranking from that, does not compare two drugs. It compares two trial designs.
A network meta-analysis does precisely not do that. It calculates across the shared comparator anchors of all included trials and estimates how the drugs would stand against each other had they been tested head to head directly.
Methodology
Systematic review and network meta-analysis across 24 endpoints, using frequentist random-effects models and Bayesian dose-response models. Certainty of evidence rated by GRADE, risk of bias assessed with Cochrane Risk of Bias 2. Medline, Embase and the Cochrane Library were searched up to 12 November 2025. Randomised controlled trials of at least twelve weeks' duration were included.
Where retatrutide actually appears
For the one-year comparison against lifestyle modification alone, the study lists the following figures at moderate to high certainty:
- Weight reduction at 1 year
- -14.9%
- 95% confidence interval
- -16.0 to -13.9
- Weight reduction at 1 year
- -14.8%
- 95% confidence interval
- -16.9 to -12.7
- Weight reduction at 1 year
- -10.9%
- 95% confidence interval
- -12.7 to -9.1
- Weight reduction at 1 year
- -9.9%
- 95% confidence interval
- -12.4 to -7.5
- Weight reduction at 1 year
- -9.8%
- 95% confidence interval
- -10.6 to -9.1
- Weight reduction at 1 year
- -8.1%
- 95% confidence interval
- -9.7 to -6.5
Retatrutide does not appear in any of these rows. Instead, the authors group it together with ecnoglutide and mazdutide under "emerging agents" and write that these could achieve similar or larger reductions, with figures between 13.1 and 14.6 percent and a rating of very low to low certainty. Which of these three drugs sits where within that range is not stated.
What 'very low to low certainty' actually means
It is a GRADE rating and does not mean a drug is weak. It means the available data support the estimate only weakly, and the true value could sit well above or below it.
The factors that generally lower a GRADE rating are few or small trials, short durations, indirect rather than direct comparisons, high heterogeneity and risk of bias. Which of these applied here is not stated in the abstract. A low rating is, in every case, a statement about the state of knowledge, not about the substance.
That is exactly why the range does not serve as evidence in either direction. It is an estimate with explicitly low certainty, and it is not even attributed to retatrutide alone.
Where the community gets ahead of the evidence
On forums, on advice sites and in video descriptions, retatrutide is widely held to be the strongest available drug. That conviction rests on real trial figures, but it draws from them a comparison that none of the trials actually made.
Three claims come up again and again, and for all three we found no published basis:
First, the conversion. Specific schemes circulate that claim to translate a tirzepatide dose into a retatrutide dose. Based on our research, no such equivalence has ever been published or validated. The two molecules act on a different number of receptors and have different pharmacokinetic properties. We deliberately do not cite any of these figures here, because no published basis exists for them.
Second, 'works when others fail'. Based on our research, no published study exists on retatrutide in people who did not respond to semaglutide or tirzepatide. The claim is therefore currently neither proven nor disproven, and it rests on anecdotal reports.
Third, complete appetite suppression. Appetite reduction has been measured across the entire drug class. A qualitatively different, complete suppression specific to retatrutide has not been isolated in any trial.
The actual gap between confidence and evidence
What stands out about this situation is the direction: normally the literature is more optimistic than the user community. Here it is the other way round. The community is confident. The one piece of work built specifically to compare fairly is not.
Muscle mass: the question these data cannot answer
The BMJ study reports two figures for tirzepatide side by side: it reduced fat mass the most of all compared drugs, by 25.7 percent, but it also reduced lean mass the most, by 8.3 percent.
For retatrutide, there is a separate body-composition investigation, a pre-specified substudy of a phase 2 trial in type 2 diabetes across 42 US centres (Lancet Diabetes & Endocrinology, PMID 40609566). It measured, by DXA, the percentage change in total fat mass at 36 weeks:
- Reduction in total fat mass
- 26.1%
- Reduction in total fat mass
- 23.2%
- Reduction in total fat mass
- 15.2%
- Reduction in total fat mass
- 4.9%
- Reduction in total fat mass
- 2.6%
- Reduction in total fat mass
- 4.5%
Why these two tables are not comparable
The substudy had no tirzepatide arm. It compared against placebo and dulaglutide, in a population with type 2 diabetes, over 36 weeks. Of the 189 people enrolled, only 103 ended up with both a baseline and a week-36 DXA scan.
The question of whether retatrutide preserves more muscle mass than tirzepatide cannot currently be answered with published data. Placing the 8.3 percent from the BMJ study next to a figure from this substudy makes exactly the mistake this article describes.
How weight loss generally affects lean mass is something we have covered separately: GLP-1 and muscle loss.
What else the analysis shows
Three findings from the same study are rarely cited, because they make poor marketing copy.
Only one drug reduced all-cause mortality. Subcutaneous semaglutide reduced it with a risk ratio of 0.81 (0.72 to 0.93), and likewise reduced the risk of myocardial infarction (0.72, 0.61 to 0.85). The authors note that these estimates come largely from cardiovascular outcome trials in high-risk populations. Subcutaneous semaglutide (0.43, 0.21 to 0.84) and tirzepatide (0.49, 0.27 to 0.88) also reduced the risk of heart failure.
Discontinuations due to side effects were substantial. Highest for orforglipron, naltrexone-bupropion, liraglutide, phentermine-topiramate, CagriSema and oral semaglutide, with risk ratios of 1.9 to 4.2. Gastrointestinal events were most elevated for naltrexone-bupropion, oral semaglutide, orforglipron and tirzepatide, with risk ratios of 3.1 to 4.2.
Fatigue is its own issue. Particularly under naltrexone-bupropion (risk ratio 8.9, an absolute 331 additional cases per 1000 people per year), orforglipron (3.4, plus 100 per 1000) and CagriSema (3.2, plus 92 per 1000).
And a null finding: No drug convincingly reduced the risk of kidney failure or improved quality of life, based on 43 trials with 45,663 participants.
Context for research use
All figures cited here come from controlled trials: defined preparations, fixed titration schedules, medical supervision, scheduled follow-up visits. They describe what was measured under these conditions, and nothing beyond that.
Retatrutide is not approved as a medicine anywhere. On approval status and the legal situation in the EU, we have a dedicated overview: Retatrutide approval status. For a comparison of the three drugs based on their respective trial programmes, see Retatrutide, tirzepatide and semaglutide compared.
Frequently asked questions
Sources
Nong K, Shi Q, Xie X, et al. Comparative effects of drugs for adults with overweight or obesity: systematic review and network meta-analysis. BMJ, 8 July 2026. PubMed ID 42419792.
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 & Endocrinology, August 2025. PubMed ID 40609566, ClinicalTrials.gov NCT04867785.
For research use only. Not for human consumption. Nothing in this article constitutes medical advice, a dosing recommendation, or a claim of therapeutic benefit. The substances described are not approved as medicines.
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