Ranked by human evidence

Best Peptides for Weight Loss, Ranked by Human Evidence

Semaglutide and tirzepatide have the strongest human evidence for weight and fat loss, from randomised trials reviewed by FDA, and both are prescription medicines. Of the unapproved options, retatrutide has published trial results but no FDA review, and AOD-9604's developer reported its obesity trial failed. I found no published human trial of HGH Fragment 176-191.

Semaglutide and tirzepatide (the GLP-1 medicines) have strong human-trial evidence for weight, but they are approved prescription medicines, not research compounds. They need a licensed clinician, not a supplier.

Peptides for weight loss, ranked by human evidence

The order is the strength of human evidence, strongest first: strong, moderate, limited, animal or lab only, then none. Ties keep the site's usual compound order. A higher rank means more and better human studies, not that a compound works for weight loss, so check what each study measured.

Peptides for weight loss compared: evidence level, US legal status and what human studies measured
Rank	Compound	Evidence	US status	Measured in humans	Guide
1	Semaglutide	Strong human evidence	FDA-approved · prescription only	Weight, blood sugar and cardiovascular outcomes in the randomised trials behind its FDA approvals.	Read
2	Tirzepatide	Strong human evidence	FDA-approved · prescription only	Weight, blood sugar, cardiovascular risk and sleep apnoea in the placebo-controlled trials behind its approvals.	Read
3	Liraglutide	Strong human evidence	FDA-approved · prescription only	Weight and blood sugar in the placebo-controlled trials behind Saxenda and Victoza.	Read
4	Orforglipron	Strong human evidence	FDA-approved · prescription only	Weight in placebo-controlled Phase 3 trials, leading to approval as Foundayo in April 2026. A pill, not a peptide.	Read
5	Tesamorelin	Strong human evidence	FDA-approved · prescription only	Visceral belly fat in people with HIV (26 randomised trials); never tested in healthy adults for body composition.	Read
6	L-Carnitine (injection)	Strong human evidence	FDA-approved · prescription only	Its approved use in diagnosed carnitine deficiency, including dialysis patients; for weight, a meta-analysis of 37 trials of oral L-carnitine found a modest drop.	Read
7	Retatrutide	Moderate human evidence	Research use only	Weight in a 48-week Phase 2 trial of 338 adults and in Phase 3 trials; FDA has reviewed none of it.	Read
8	Cagrilintide	Moderate human evidence	Research use only	Weight with semaglutide (CagriSema) in Phase 3: 20.4% loss against 3.0% on placebo at 68 weeks.	Read
9	Survodutide	Moderate human evidence	Research use only	Weight in a Phase 3 trial of 725 adults: 12.2% to 13.0% loss against 5.4% on placebo at 76 weeks.	Read
10	Mazdutide	Moderate human evidence	Research use only	Weight in a US Phase 2 trial and Chinese Phase 3 programmes; approved in China, never reviewed by FDA.	Read
11	AOD-9604	Limited human data	Unapproved drug	Safety in 6 placebo-controlled trials; efficacy was never published, and the developer reported its obesity trial failed.	Read
12	Tesofensine	Limited human data	Unapproved drug	Weight in placebo-controlled obesity trials, including a Phase 3 programme in Mexico reported by the developer's partner. Not a peptide.	Read
13	Eloralintide	Limited human data	Unapproved drug	Weight in one 48-week Phase 2 trial, with loss rising with dose; not yet replicated.	Read
14	5-Amino-1MQ	Animal / lab only	Unapproved drug	None I could find: every efficacy result I located comes from mice.	Read
15	MOTS-c	Animal / lab only	Research use only	Only the body's own MOTS-c levels, for example after exercise; no completed trial has given it to people.	Read
16	HGH Fragment 176-191	Animal / lab only	Unapproved drug	None I could find for this exact sequence; only rat and cell studies.	Read
17	Adipotide	Animal / lab only	Unapproved drug	No reported human outcome; its only human trial, in prostate cancer, ended early without results.	Read

Prescription / GLP-1FDA-approved · prescription only
1. Semaglutide
Strong human evidence
Measured in humans: Weight, blood sugar and cardiovascular outcomes in the randomised trials behind its FDA approvals.
Why this rating
FDA has approved semaglutide products for several separate indications, each cleared on randomised trials reviewed by the agency: glycemic control in type 2 diabetes (Ozempic, approved 2017), cardiovascular and chronic-kidney-disease risk reduction in type 2 diabetes (Ozempic), chronic weight management (Wegovy, approved 2021), and cardiovascular risk reduction in adults with obesity or overweight and established cardiovascular disease (Wegovy). The adverse-reaction rates on the approved label come from that trial data. This rating describes the approved product, not the grey-market research-chemical vials sold under the same name.
Prescription / GLP-1FDA-approved · prescription only
2. Tirzepatide
Strong human evidence
Measured in humans: Weight, blood sugar, cardiovascular risk and sleep apnoea in the placebo-controlled trials behind its approvals.
Why this rating
FDA has approved tirzepatide products for four indications across two brands, each cleared on placebo-controlled randomised trials reviewed by the agency: glycemic control and cardiovascular risk reduction in type 2 diabetes (Mounjaro, approved 2022), and chronic weight management and obstructive sleep apnoea (Zepbound, approved from 2023). The adverse-reaction rates on the approved label come from that trial data. This rating describes the approved product, not grey-market vials sold under the same name.
Prescription / GLP-1FDA-approved · prescription only
3. Liraglutide
Strong human evidence
Measured in humans: Weight and blood sugar in the placebo-controlled trials behind Saxenda and Victoza.
Why this rating
FDA first approved liraglutide (Victoza) in 2010 for type 2 diabetes, later adding a cardiovascular-risk-reduction indication, and separately approved liraglutide (Saxenda) for chronic weight management. Each approval was cleared on placebo-controlled randomised trials reviewed by the agency, and the dosing and adverse-reaction figures on this page come from those approved labels. This rating describes the approved product, not any grey-market vial sold under the same name.
Prescription / GLP-1FDA-approved · prescription only
4. Orforglipron
Strong human evidence
Measured in humans: Weight in placebo-controlled Phase 3 trials, leading to approval as Foundayo in April 2026. A pill, not a peptide.
Why this rating
FDA approved Foundayo (orforglipron) on 1 April 2026 for chronic weight management, reviewed against placebo-controlled Phase 3 trial data under the same approval standard applied to semaglutide and tirzepatide. The adverse-reaction rates on this page come from that approved label. A type 2 diabetes indication is separately in trials and is not yet approved - this rating describes only the approved weight-management use.
Prescription / GLP-1FDA-approved · prescription only
5. Tesamorelin
Strong human evidence
Measured in humans: Visceral belly fat in people with HIV (26 randomised trials); never tested in healthy adults for body composition.
Why this rating
Twenty-six randomised controlled trials, including a randomised trial in JAMA measuring visceral and liver fat, plus safety and metabolic studies and more recent evaluation in people taking integrase inhibitors. The rating describes the volume and design of the evidence for the approved indication; no trial has tested healthy adults for body composition.
Prescription / GLP-1FDA-approved · prescription only
6. L-Carnitine (injection)
Strong human evidence
Measured in humans: Its approved use in diagnosed carnitine deficiency, including dialysis patients; for weight, a meta-analysis of 37 trials of oral L-carnitine found a modest drop.
Why this rating
FDA approved CARNITOR injection based on trials in its approved population: patients with an inborn error of metabolism causing secondary carnitine deficiency, and dialysis patients with carnitine deficiency, including a dose-ranging study in end-stage renal disease patients on hemodialysis. That approval and evidence base is specific to diagnosed deficiency, not to fat loss in someone without it. For the separate off-label weight-loss use, the best evidence I verified is a meta-analysis of 37 randomized trials of oral (not injectable) L-carnitine, finding a modest reduction in body weight and fat mass in adults, though only the body-weight effect held in the high-quality trials and the dose-response link was for body weight alone - real human RCT evidence, but for a different route and a different population than the injection sold in weight-loss clinics.
Research peptidesResearch use only
7. Retatrutide
Moderate human evidence
Measured in humans: Weight in a 48-week Phase 2 trial of 338 adults and in Phase 3 trials; FDA has reviewed none of it.
Why this rating
Multiple randomised, double-blind, placebo-controlled Phase 3 trials have been run in humans, confirmed this session on the ClinicalTrials.gov registry: a completed obesity trial (TRIUMPH-1, 2,335 participants, primary endpoint at week 80) and an ongoing roughly 10,000-person cardiovascular and kidney outcomes trial (TRIUMPH-Outcomes). Neither has posted results to the public registry, and TRIUMPH-1's figures so far are topline numbers from the sponsor's own press release. Peer-reviewed results have been published from other trials: a 48-week Phase 2 obesity trial of 338 adults (NEJM, 2023; -24.2% body weight on 12 mg against -2.1% on placebo) and TRANSCEND-T2D-1, a 40-week Phase 3 trial of 537 adults with type 2 diabetes (The Lancet, 2026; weight -11.5% to -15.3% against -2.6%). All were funded by the developer, and none of the data has been reviewed by FDA.
Research peptidesResearch use only
8. Cagrilintide
Moderate human evidence
Measured in humans: Weight with semaglutide (CagriSema) in Phase 3: 20.4% loss against 3.0% on placebo at 68 weeks.
Why this rating
Multiple randomised, double-blind, placebo-controlled Phase 3 trials of cagrilintide, alone and combined with semaglutide as CagriSema, have been run in humans, confirmed this session on the ClinicalTrials.gov registry (REDEFINE 1, primary endpoint percent body weight change at week 68). REDEFINE 1, with 3,417 participants randomised, was published in the New England Journal of Medicine in 2025: mean weight loss of 20.4% on CagriSema against 3.0% on placebo at 68 weeks, counting everyone as randomised; the sponsor's press release adds 22.7% among those who stayed on treatment. No results are posted to the public registry as of this writing, the trials were funded by the sponsor, and none of the data has been reviewed by FDA.
Research peptidesResearch use only
9. Survodutide
Moderate human evidence
Measured in humans: Weight in a Phase 3 trial of 725 adults: 12.2% to 13.0% loss against 5.4% on placebo at 76 weeks.
Why this rating
Two Phase 3, randomised, double-blind, placebo-controlled trials are registered and completed per ClinicalTrials.gov: SYNCHRONIZE-1 (weight loss without diabetes; primary completion 2 December 2025, study completion 20 February 2026) and SYNCHRONIZE-CVOT (cardiovascular safety, completed 30 June 2026), both sponsored by Boehringer Ingelheim. SYNCHRONIZE-1 is published in the New England Journal of Medicine (2026): among 725 adults, average weight fell 12.2% on survodutide up to 3.6 mg and 13.0% on up to 6.0 mg at 76 weeks, against 5.4% on placebo. SYNCHRONIZE-CVOT results were not published in a source this page checked, and no regulator has yet reviewed or approved survodutide for any indication.
Research peptidesResearch use only
10. Mazdutide
Moderate human evidence
Measured in humans: Weight in a US Phase 2 trial and Chinese Phase 3 programmes; approved in China, never reviewed by FDA.
Why this rating
A US-based, multicentre, placebo-controlled phase 2 trial in adults with obesity or overweight reported dose-ranging efficacy and safety data supporting later-stage development. Mazdutide has since been approved by China's National Medical Products Administration (NMPA) for chronic weight management and for glycemic control in type 2 diabetes, each following its own phase 3 programme in Chinese adults - real regulatory review, but not an FDA review, and I could not verify the phase 3 trial results directly against a peer-reviewed publication for every claim in Innovent's own announcements.
Research peptidesUnapproved drug
11. AOD-9604
Limited human data
Measured in humans: Safety in 6 placebo-controlled trials; efficacy was never published, and the developer reported its obesity trial failed.
Why this rating
AOD-9604 is unusual among grey-market fat-loss peptides in that its developer ran six randomised, double-blind, placebo-controlled human trials, giving it by mouth for up to 24 weeks or as single intravenous doses. Their safety data were published in 2013 (Stier, Vos and Kenley, Journal of Endocrinology and Metabolism) and report adverse events at rates similar to placebo, with no change in IGF-1 or glucose tolerance. Their efficacy results were never published, and the company's announcements and news reports on the 2007 discontinuation of its obesity programme state its Phase IIb trial did not meet its primary endpoint against placebo, after which clinical development for weight loss stopped. Developer-funded safety data with no published efficacy data keeps this at "limited" rather than a higher tier, and the efficacy account that exists does not favour the effect it is marketed for.
Research peptidesUnapproved drug
12. Tesofensine
Limited human data
Measured in humans: Weight in placebo-controlled obesity trials, including a Phase 3 programme in Mexico reported by the developer's partner. Not a peptide.
Why this rating
Unlike most compounds in this cluster, tesofensine has completed placebo-controlled human obesity trials, including a Phase 3 programme run in Mexico that its developer's commercial partner reported as meeting its primary and secondary endpoints. I rate this 'limited' rather than higher because none of that trial data sits in a source I can independently verify and cite here - it comes from sponsor press releases and public regulatory correspondence, not a peer-reviewed record in my source registry - and because no medicines regulator anywhere had approved it as of the most recent public update I could confirm.
Research peptidesUnapproved drug
13. Eloralintide
Limited human data
Measured in humans: Weight in one 48-week Phase 2 trial, with loss rising with dose; not yet replicated.
Why this rating
A 48-week, multicentre, double-blind, randomised, placebo-controlled phase 2 trial in adults with obesity or overweight reported dose-dependent weight loss across several fixed and titrated dose arms, with a favourable tolerability profile Lilly has publicised. That is real human randomised-trial evidence, at the strongest single-trial level this page recognises for a compound with only one published human efficacy trial - but it is one trial, not yet replicated, and eloralintide remains in Lilly's own pipeline rather than approved anywhere.
Research peptidesUnapproved drug
14. 5-Amino-1MQ
Animal / lab only
Measured in humans: None I could find: every efficacy result I located comes from mice.
Why this rating
Every efficacy finding I could locate - reversal of diet-induced obesity, improved glucose tolerance - comes from mouse experiments. I could not find a published human trial of any phase, nor any published human pharmacokinetic, safety or dosing data. That places it below compounds on this site that have at least one small, flawed human trial behind them.
Research peptidesResearch use only
15. MOTS-c
Animal / lab only
Measured in humans: Only the body's own MOTS-c levels, for example after exercise; no completed trial has given it to people.
Why this rating
The four human records tagged as randomised trials all measure endogenous MOTS-c responding to exercise, metformin or heat stress. None administers MOTS-c to anyone. One Phase 2 trial giving subcutaneous MOTS-c to adults with prediabetes is recruiting, with primary completion due February 2027, and has reported nothing.
Research peptidesUnapproved drug
16. HGH Fragment 176-191
Animal / lab only
Measured in humans: None I could find for this exact sequence; only rat and cell studies.
Why this rating
The only peptide from this region of hGH to reach a randomised human obesity trial is AOD-9604 - a related but different molecule (177-191 plus an added tyrosine). I could not locate any published human trial of the unmodified 176-191 sequence sold under this name. What exists is a 1978 rat study of this and other C-terminal hGH fragments, which found a hyperglycemic and insulin-raising effect rather than a fat-loss one, and a 2022 laboratory study pairing it with a cancer drug in cell culture - unrelated to weight loss. That is animal and in-vitro data only, with no human evidence at all for the fat-loss claim it is marketed on.
Research peptidesUnapproved drug
17. Adipotide
Animal / lab only
Measured in humans: No reported human outcome; its only human trial, in prostate cancer, ended early without results.
Why this rating
The evidence runs mouse to primate and stops there. A 2004 mouse study established the mechanism and reversed obesity in mice without a detectable adverse effect in that species. A 2011 study across three Old World primate species reproduced meaningful weight loss and improved insulin resistance at an optimal dose, but also surfaced a dose-dependent kidney-injury signal that the mouse study never showed. The only human study - a first-in-human Phase 1 trial in men with prostate cancer - enrolled a handful of patients before being terminated early at the investigator's request, and never published a result in either direction. That gap keeps this at preclinical rather than a higher tier: real primate efficacy and safety data exist, but no human efficacy or safety outcome has ever been reported.

Common questions about peptides for weight loss

What is the strongest peptide for fat loss?

By human evidence, the approved GLP-1 medicines semaglutide (Wegovy) and tirzepatide (Zepbound), both cleared by FDA for chronic weight management on randomised trials. Retatrutide, still in trials, cut body weight by 24.2% on the 12 mg dose over 48 weeks in its Phase 2 trial, against 2.1% on placebo. FDA has reviewed none of its data.

Is there a peptide that targets belly fat?

Tesamorelin is the only peptide on this list approved for belly fat: FDA cleared it to reduce excess visceral (deep abdominal) fat in people with HIV-associated lipodystrophy. No trial has tested it for body composition in healthy adults. HGH Fragment 176-191 is sold for fat loss, but I found no published human trial of that sequence.

Do you need a prescription for weight-loss peptides?

For the approved medicines, yes: semaglutide, tirzepatide, liraglutide, orforglipron, tesamorelin and L-carnitine injection all need a prescriber. Retatrutide, cagrilintide and the other unapproved compounds have no FDA-approved product, and FDA says retatrutide and cagrilintide cannot be used in compounding. A 'research use only' vial is not the approved product, even when the name matches.

What are the side effects of cagrilintide?

In a Phase 2 trial, nausea, constipation and diarrhoea affected 41-63% of people on cagrilintide, rising with dose, against 32% on placebo. Combined with semaglutide as CagriSema in REDEFINE 1, gut side effects affected 79.6% against 39.9% on placebo, mostly passing and mild to moderate. With no FDA-reviewed label, there is no regulator-confirmed full list.

What are the downsides of weight-loss peptides?

Semaglutide, tirzepatide and liraglutide carry a boxed warning and published side-effect rates on their labels, and they need a prescriber. Compounded and 'research use only' vials sold under the same names are not the approved products, and FDA has documented dosing errors, counterfeit product and fraudulent labelling in that market. Of the research-chemical options, AOD-9604's developer reported that its obesity trial failed.

Peptides for weight loss, ranked by human evidence

Common questions about peptides for weight loss

Guides on peptides for weight loss

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AOD-9604 Dosage Chart and Calculator: Protocol and Trial Data

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Cagrilintide Dosage Chart and Calculator: Protocol, Trial Doses

Cagrilintide: Dosage, Side Effects and Legal Status

CagriSema Dosage: REDEFINE Trial Doses, Blend Vials and Filing Status

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Semaglutide vs Tirzepatide: The Two FDA Labels Side by Side

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