peptides for weight loss

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.
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.
semaglutide (tier S) · glp-1 agonist. 14.9% body weight in STEP 1 (NEJM 2021). 20% MACE reduction in SELECT (NEJM 2023).
liraglutide (tier S) · first daily glp-1, fda-approved as saxenda for obesity. ~8% mean weight loss in pivotal trials.
cagrisema (tier B) · novo's semaglutide + cagrilintide combo. missed non-inferiority vs tirzepatide in REDEFINE-4, february 2026.
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.
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.
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.
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.

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.
hgh (tier S) · recombinant human growth hormone, fda-approved 1985 for pediatric gh deficiency. multiple adult indications since.
sermorelin (tier A) · ghrh(1-29) analog that stimulates endogenous gh release. fda-approved 1997 for pediatric gh deficiency, voluntarily withdrawn from us market by serono 2008.
mots-c (tier B) · 16-amino-acid peptide encoded inside the mitochondrial 12S rRNA. discovered by Lee et al, Cell Metab 2015.
hgh frag 176-191 (tier C) · lipolytic c-terminal fragment of hgh.
aod-9604 (tier D) · the hgh 176-191 fragment with tyrosine added for stability.
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.
atx-304 (formerly o304) (tier B) · investigational oral ampk activator. one 65-person, 28-day randomized diabetes trial plus a small obesity conference report.
sana (mvd1) (tier B) · creatine-thermogenesis small molecule with mouse fat-loss data and a 41-person phase 1 PK and safety study.
bam15 (tier C) · mitochondrial protonophore with oral PK and fat-mass findings in mice. no published human exposure.
2,4-dinitrophenol (dnp) (tier F) · historical weight-loss poison and mitochondrial uncoupler with documented hyperthermia, organ failure, and deaths.
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.
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.
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.
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.
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.
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.
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.

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.

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