peptides for weight loss

updated

the strongest obesity outcomes sit in the incretin class, while non-incretin human trials and high-risk research compounds need separate evidence lanes.

incretin medicines carry the deepest obesity record, but they are not the only compounds with randomized human weight data. bimagrumab and tesofensine have direct trial outcomes with different routes, mechanisms, maturity, and caveats; l-carnitine's average effect is modest and inconsistent; cardarine has no proven weight-loss outcome and a severe toxicology boundary.

eloralintide has a phase-2 weight result and an unreported phase-3 program; brenipatide has registrations without posted results; SLU-PP-332 has mouse outcomes without human administration. SLU-PP-915 is a separate molecule and does not inherit those results.

the glp-1 class.

approved benchmarks and late-stage challengers. the cleanest evidence shelf in weight-loss peptides.

  • tirzepatide (tier S) · dual gip/glp-1 agonist. 22.5% body weight loss at top dose. SURMOUNT-1, NEJM 2022. · the highest-efficacy peptide currently fda-approved for obesity. zepbound for obesity, mounjaro for diabetes. the trial number is the trial number.
  • retatrutide (tier S) · triple gip/glp-1/glucagon agonist. 24.2% at 48 weeks in phase 2, then 28.3% at 80 weeks in TRIUMPH-1 phase 3. not approved. · lilly's next-generation incretin. still in trials, not approved. when it lands, the floor moves again.
  • semaglutide (tier S) · glp-1 agonist. 14.9% body weight in STEP 1 (NEJM 2021). 20% MACE reduction in SELECT (NEJM 2023). · the molecule that built the category. ozempic, wegovy. SELECT is the trial that turned the cosmetic-drug argument into a medical-drug argument.
  • liraglutide (tier S) · first daily glp-1, fda-approved as saxenda for obesity. ~8% mean weight loss in pivotal trials. · the daily-dosing original. weekly molecules ate its lunch. still prescribed, just not where most of the action sits.
  • cagrisema (tier B) · novo's semaglutide + cagrilintide combo. missed non-inferiority vs tirzepatide in REDEFINE-4, february 2026. · novo's swing at tirzepatide. REDEFINE-1 reported 22.7% mean weight loss at 68 weeks (trial-product estimand). REDEFINE-4 open-label head-to-head against tirzepatide 15 mg at 84 weeks reported cagrisema 23.0% vs tirzepatide 25.5%; failed non-inferiority on the primary endpoint. NDA filed december 18, 2025; PDUFA decision expected late 2026. repositioned as a tolerability story rather than a peak-efficacy story.
  • orforglipron (tier S) · the first non-peptide oral glp-1. ~12.4% body weight at the top dose in ATTAIN-1. fda-approved as foundayo, april 2026. · a small molecule, not a peptide, but it hits the same glp-1 receptor as a once-daily pill with no food or water restriction. approval lands it in S. the effect size trails the best injectables; the access story, a pill with no cold chain, is the headline.
  • survodutide (tier A) · glp-1 / glucagon dual agonist (boehringer / zealand). ~16.6% body weight at 76 weeks in SYNCHRONIZE-1; fda breakthrough therapy for MASH. · the glucagon arm adds energy expenditure and a liver-fat angle on top of glp-1. phase 3 is global and has reported, not yet approved. the MASH program is the part to watch.
  • mazdutide (tier A) · glp-1 / glucagon dual agonist (innovent / lilly). ~14% at 6 mg in GLORY-1, ~20% at 9 mg in GLORY-2. approved in china. · an oxyntomodulin analog that reached approval first, in china, on real phase-3 numbers. no fda filing yet, and the pivotal data is single-ethnicity, which keeps it at A rather than S.
  • cagrilintide (tier B) · novo's long-acting amylin analog. 11.8% body weight at 68 weeks as monotherapy in the phase-3 REDEFINE-1 trial. · a different appetite hormone than glp-1, and the second mechanism inside cagrisema. on its own it beat liraglutide head-to-head in phase 2 and posted 11.8% in phase 3, but the standalone is unapproved and the filed product is the combo.

same name-recognition, different evidence questions.

the messy half of the category. some are s-tier drugs by the sitewide evidence ranking, just not obesity drugs. some are failed fat-loss bets. some are research compounds the market talks about as if the human data already exists.

  • tesamorelin (tier S) · ghrh analog approved (egrifta, fda 2010) for hiv-associated visceral lipodystrophy. · the visceral-fat indication is approval-grade. reduced visceral adipose tissue ~15-18% in the pivotal trial (Falutz et al, NEJM 2007, n=412). that record belongs in any weight-loss reference. it does not turn tesamorelin into a general obesity drug.
  • hgh (tier S) · recombinant human growth hormone, fda-approved 1985 for pediatric gh deficiency. multiple adult indications since. · s-tier as a real drug with serious biology. in weight-loss context the relevant evidence is body-composition shifts in gh-deficient adults, not obesity outcomes in metabolically healthy people. hgh is not an obesity drug.
  • sermorelin (tier B) · ghrh(1-29) analog that stimulates endogenous gh release. fda-approved 1997 for pediatric gh deficiency, voluntarily withdrawn from us market by serono 2008. · still compounded and prescribed off-label by anti-aging clinics for adult fat loss. published effect sizes outside the deficiency context are modest. raises endogenous gh and igf-1 within physiologic range, not the supraphysiologic territory of exogenous hgh.
  • mots-c (tier B) · 16-amino-acid peptide encoded inside the mitochondrial 12S rRNA. discovered by Lee et al, Cell Metab 2015. · preclinical biology shows ampk activation and improved insulin sensitivity in mice. human evidence is one small healthy-volunteer pharmacokinetic study. weight-loss-specific controlled trials: zero.
  • hgh frag 176-191 (tier C) · lipolytic c-terminal fragment of hgh. · lipolytic activity in vitro and in rodent models. aod-9604 is the tyrosine-modified stable analog that took the fragment into phase 2 and missed every obesity endpoint. the unmodified fragment has no controlled human weight-loss trial.
  • aod-9604 (tier D) · the hgh 176-191 fragment with tyrosine added for stability. · ran phase-2 obesity trials at metabolic pharmaceuticals. didn't hit endpoints. fda gras status as a food additive (2014) is not drug approval and not weight-loss efficacy clearance. still sold by research-chemical vendors.
  • 5-amino-1mq (tier C) · small molecule NNMT inhibitor. the 2018 subcutaneous mouse study measured a 5.1 percent baseline weight loss over 11 days. zero human administration studies located. · the target and mouse findings are real. the human benefit and safety record is empty, and commercial oral or subcutaneous claims do not fill it.
  • atx-304 (formerly o304) (tier B) · investigational oral ampk activator. one 65-person, 28-day randomized diabetes trial plus a small obesity conference report. · atx-304 has more human evidence than most research chemicals in this lane, but it is still an early program. the published trial measured short-term metabolic and vascular signals, not durable obesity outcomes. no human terminal half-life or long-term safety file has been published.
  • sana (mvd1) (tier B) · creatine-thermogenesis small molecule with mouse fat-loss data and a 41-person phase 1 PK and safety study. · the human study established a short exposure curve and a direct warning: two of three participants at the highest single dose developed reversible renal tubular injury. it did not test human weight loss or establish a protocol.
  • bam15 (tier C) · mitochondrial protonophore with oral PK and fat-mass findings in mice. no published human exposure. · bam15 looked more controllable than older uncouplers in the reported mouse program. that is an animal result, not a human thermal, cardiac, hepatic, reproductive, or overdose safety margin. the 1.7-hour half-life belongs to mouse plasma only.
  • 2,4-dinitrophenol (dnp) (tier F) · historical weight-loss poison and mitochondrial uncoupler with documented hyperthermia, organ failure, and deaths. · dnp is an industrial chemical that was sold for weight loss before modern drug approval law. it has no established antidote or safe exposure, and historical weight change does not redeem the mechanism's lethal unpredictability.
  • L-carnitine (tier A) · Levocarnitine is an endogenous fatty-acid carrier with approved deficiency indications and modest, inconsistent weight-loss evidence. The approved injection is intravenous and indication-specific. · Across 37 randomized trials, supplementation produced a modest average weight change, while one direct oral trial in overweight women was negative. This evidence does not validate gray-market IM or SC injections.
  • Bimagrumab (tier A) · Bimagrumab is an investigational activin type II receptor antibody with randomized intravenous evidence for reducing body weight and fat mass while preserving or increasing lean mass. FDA's July 2026 Purple Book data snapshot had no bimagrumab or listed development-identifier entry when checked on August 15, 2026. · BELIEVE showed direct 48-week weight and body-composition effects in 507 adults without diabetes. The trial was completed and published, but it does not supply approval, cardiovascular-outcome, mortality, function, or post-treatment durability evidence.
  • Cardarine (tier F) · Cardarine, or GW501516, is an unapproved PPAR-beta/delta agonist with short human lipid and fuel-use biomarker studies and severe chronic animal toxicology signals. It is not a SARM. · Short controlled human studies changed lipid, liver-fat, insulin, and fuel-oxidation biomarkers. They did not establish weight loss, endurance, cardiovascular benefit, diabetes prevention, or chronic safety.
  • Tesofensine (tier B) · Tesofensine is an investigational monoamine-reuptake inhibitor with randomized oral weight-loss evidence and a material integrity caveat attached to its central trial report. · Tesofensine produced dose-related 24-week weight loss in TIPO-1 and in a Mexican regulator-registry summary. The first report has an Expression of Concern, the phase 3 summary is not a peer-reviewed full report, and no final Mexican or US authorization was verified.
  • SLU-PP-332 (tier C) · SLU-PP-332 is a small-molecule pan-ERR agonist with mouse endurance and metabolic results, ex vivo human myoblast work, no oral bioavailability, and no human administration study. · SLU-PP-332 activates an oxidative exercise-response program and improved specific outcomes in mice. It has not been administered to people in the located record.
  • brenipatide (tier C) · Brenipatide, Lilly code LY3537031, is a modified 39 amino acid peptide that activates both GIP and GLP-1 receptors. The registry has 11 records indexed under Brenipatide and 5 earlier LY3537031-only registrations. None of the 16 has posted results. · Brenipatide is an investigational subcutaneous dual GIP and GLP-1 receptor agonist being studied in people. The registered program is large, but effect and safety remain unknown because no record has posted results.
  • eloralintide (tier B) · a weight-loss drug eli lilly is still testing, given in trials as a once-a-week injection under the skin. it copies amylin, the fullness hormone the pancreas releases with insulin at a meal. 20% weight loss at 48 weeks in one 263-person phase 2, and 64.3% nausea in the fixed 6 mg arm. five phase 3 trials are enrolling and none reads out before 2028. · a weight-loss drug eli lilly has in development, given as a once-a-week injection under the skin, which works by turning up the body's own after-meal fullness signal. formally an amylin receptor agonist, code LY3841136. one published 48-week phase 2 (NCT06230523, n=263) produced up to 20% mean weight loss with no incretin anywhere in the molecule. eli lilly sponsors every trial on the record, the phase 3 programme has yet to report, and nausea reached 64.3% in the fixed 6 mg arm, which the selectivity pitch did not predict.

specific-question reference.

which peptide has the largest published weight-loss effect size?

retatrutide has the largest published investigational signal: 24.2% in phase 2 at 48 weeks, then 28.3% in TRIUMPH-1 phase 3 at 80 weeks. it is not approved. among approved drugs, tirzepatide leads with 22.5% body weight loss at 72 weeks at top dose in SURMOUNT-1. semaglutide hit 14.9% in STEP 1.

is there an oral fda-approved option for weight loss?

yes. orforglipron (foundayo). the first oral small-molecule glp-1 receptor agonist approved for chronic weight management, april 2026. not a peptide. solves the no-needles question telehealth has been begging for.

what does the trial data show about peptides and visceral fat?

tirzepatide and semaglutide trials report visceral adipose reduction alongside total weight loss. tesamorelin is fda-approved specifically for hiv-associated visceral lipodystrophy, the cleanest visceral-fat-specific indication in the category. hgh has body-composition biology and approved endocrine indications, but it is not an obesity drug. those are separate evidence buckets.

what's in the trial record for body recomposition?

the gh-axis literature (cjc-1295, ipamorelin, sermorelin, tesamorelin) reports modest lean-mass and fat-mass shifts in healthy adults. magnitudes are real but smaller than the magnitude of fat loss reported on the glp-1 class. body recomp without weight loss is not a problem these compounds solve at meaningful scale in the trial record.

are there sex-specific differences in the glp-1 weight-loss data?

SURMOUNT (tirzepatide) and STEP (semaglutide) both enrolled men and women, both reported broadly similar mean outcomes across sexes. the published record does not turn that into a one-size-fits-all dosing story.

how does the gray-market research-peptide evidence compare to the fda-approved evidence?

different evidence categories. fda-approved peptides have multi-thousand-patient phase-3 rcts. atx-304 and sana have small early human programs, while bam15 and 5-amino-1mq remain animal-only. dnp has human evidence because it has poisoned people; that is not therapeutic validation. treating any of these records as interchangeable is the category error.

what the safety literature says.

what gi side effects show up in the glp-1 record?

nausea (~40% at initiation), vomiting (15-25%), constipation, diarrhea. usually transient over the first 4-8 weeks, dose-dependent. all on the fda labels as common adverse events. not surprises.

what does the trial record say about lean-mass loss on glp-1s?

approximately 25-40% of total mass lost is lean tissue. similar to what diet-only weight-loss trials report. ongoing research is examining the role of resistance training and protein intake during treatment.

what does the long-term safety data show for glp-1s?

20+ years of post-marketing data across the class. exenatide approved 2005. published risks: rare pancreatitis, gallbladder events, contraindication for personal or family history of medullary thyroid carcinoma or men2. SELECT (NEJM 2023) reported net cardiovascular benefit. fda surveillance ongoing for muscle/bone density and suicidal ideation. the 2024 fda review found no causal link with semaglutide.

what about the non-glp-1 peptides used in weight-loss contexts?

varies by compound. hgh, tesamorelin, and sermorelin have real medical records in specific indications. atx-304 and sana reached early human testing; sana also produced a high-dose renal signal. bam15 remains animal-only. dnp has documented lethal human toxicity and no established antidote. absence of published harm signals in a small or preclinical file is not evidence of safety.

claim checks

related comparisons

reptides grades the research record and cites the literature behind every call. research reference only; not medical advice.