Peptides for Weight Loss, by US Legal Status

Weight-loss peptides at a glance

Most peptides sold for weight loss are not FDA-approved for it. Four peptide drugs carry an FDA-approved weight indication in September 2026, and three of them are GLP-1-class drugs for general obesity; the fourth is approved only for a handful of rare conditions. Everything else marketed under the phrase "weight loss peptides" is either approved for a different purpose, failed when it was tested for weight, or has never been tested for weight in people.

The table orders each molecule by its US legal status in this index, then alphabetically. The status column restates the index's registry label; it is a legal position, not a verdict on how well a molecule works.

Approved for weight management

Three peptides are FDA-approved for chronic weight management in the general population of adults with obesity or with overweight and a weight-related condition. Semaglutide holds the indication as Wegovy, for adults and children 12 and older with obesity and for adults with overweight and a weight-related condition; the same label also covers cardiovascular risk reduction in adults with cardiovascular disease and either obesity or overweight, and a liver disease, MASH with moderate to advanced fibrosis ^[1]. Tirzepatide holds it as Zepbound, which is also approved to treat moderate to severe obstructive sleep apnea in adults with obesity ^[3]. Liraglutide holds it as Saxenda, for adults and for children 12 and older who weigh more than 60 kg and have obesity ^[5]; generic liraglutide labeled for the same use is now listed on DailyMed ^[7].

Each of the three labels frames the drug as an addition to a reduced-calorie diet and increased physical activity, not a replacement for them ^[1][3][5]. The trial results in the table were measured on that basis, against placebo groups given the same lifestyle program.

Setmelanotide is the fourth approved peptide with a weight indication, and it is the narrowest. Imcivree is approved to reduce excess body weight only in people with acquired hypothalamic obesity, Bardet-Biedl syndrome, or genetically confirmed POMC, PCSK1 or LEPR deficiency, and its label states that it is not indicated for general (polygenic) obesity because it would not be expected to work there ^[8]. Its approval rests on small trials, which is what rare diseases allow: in the single-arm phase 3 trials, 8 of 10 patients with POMC deficiency and 5 of 11 with LEPR deficiency lost at least 10 percent of body weight at about one year ^[9].

The approved peptide drugs table and the approved status page list every approved molecule in this index, including those approved for uses unrelated to weight.

Approved for something else, marketed for weight

Tesamorelin is an FDA-approved peptide, but not for weight loss. Its approval covers the reduction of excess abdominal fat in adults with HIV who have lipodystrophy, and nothing wider ^[12]. The phase 3 trial behind it enrolled HIV-infected patients and measured visceral fat, the deep abdominal compartment around the organs, rather than body weight ^[11].

The distinction matters because tesamorelin is widely sold as a general fat-loss peptide. The one randomized body-composition trial outside HIV reduced visceral fat and left the fat under the skin statistically unchanged; the review of tesamorelin's off-label use sets out that result in full.

Tested for weight loss and failed

AOD-9604, a fragment of human growth hormone, is the one molecule in this group whose human weight program ran and failed. FDA's briefing document for its December 2024 advisory committee meeting describes the sponsor's phase 2b trial in 502 randomized adults with obesity: weight loss at twelve weeks, the primary endpoint, did not differ significantly from placebo, and the sponsor terminated development for obesity in February 2007 ^[15]. FDA concluded that the available data do not support effectiveness for obesity by any route ^[15].

The committee then voted 12 to 0 against placing AOD-9604 on the section 503A bulks list ^[16]. The nomination was later withdrawn, and FDA lists the substance among those that may present significant safety risks in compounding, citing immunogenicity concerns and limited safety information ^[17].

Investigational or never tested for weight in humans

Retatrutide is a real drug candidate with real trial results and no approval. Its phase 2 obesity trial reported weight reductions of up to 24.2 percent at 48 weeks against 2.1 percent on placebo ^[13], and it remains investigational. FDA has stated that retatrutide cannot be used in compounding under federal law, is not a component of any FDA-approved drug, and has not been found safe and effective for any condition ^[14]. The review of the incretin pipeline follows its late-stage program.

MOTS-c has never been tested for weight in people. The evidence for a metabolic effect comes from mice, where it reduced diet-induced obesity and insulin resistance ^[18]. Every human trial-type record indexed for it measures the body's own circulating MOTS-c rather than administering the peptide ^[19], and FDA has stated that it identified no human exposure data on drug products containing it by any route ^[24].

Commonly called peptides, but not peptides

Several compounds sold beside weight-loss peptides are not peptides at all. A peptide is a short chain of amino acids. 5-amino-1MQ and SLU-PP-332 are small synthetic organic molecules with no amino-acid chain, and orforglipron is a small-molecule GLP-1 receptor agonist designed to be taken by mouth. Each sits outside this index, and none inherits the legal position of any peptide in the table above.

Is a compounded version lawful?

It depends on the molecule, and for most of them the answer is no or only narrowly. For semaglutide and tirzepatide, mass compounding ended when FDA declared their shortages resolved; a 503A pharmacy may still compound either for an individual patient whose prescriber documents a clinical need an approved product cannot meet, and a lower price does not qualify ^[22]. Liraglutide is a component of approved drugs and appears in no category of the 503A bulks list ^[23]. Setmelanotide and tesamorelin are approved products, and for both the approved product is the lawful route.

Retatrutide cannot be compounded under federal law, in FDA's own words ^[14]; the research-only page explains what "research use only" labeling does and does not permit. AOD-9604 was voted down by FDA's advisory committee and its nomination withdrawn ^[16][17]. MOTS-c is pending: the committee voted in July 2026 to recommend it for the 503A list, by a margin reported by two law firms because FDA has published no minutes of that meeting ^[20][21], and no final rule has followed. A recommendation is not a listing; the pending page tracks what would change that.

Elsewhere in this index