Peptides for Weight Loss: A Tiered Guide to What Is Approved, Pipeline, and Grey Market

Three different things get sold under the word peptide, and they are not comparable. One group is approved medicine with a phase 3 dossier and a prescribing label. One is late-stage pipeline that has reported very large numbers and cannot be bought legally anywhere. The third is a grey market of compounds that are unapproved, sometimes never tested in a human being, and in one case a documented trial failure that is still marketed for fat loss. This page sorts every compound you are likely to run into, states the best evidence for each, and says where a legal route exists. Status verified 23 August 2026.

What counts as a peptide here, and what does not

A peptide is a short chain of amino acids. Semaglutide is one. So are tirzepatide, retatrutide and cagrilintide. The chemistry matters for one practical reason: peptides are digested in the gut, so almost all of them are injected, and the few oral versions need absorption workarounds built into the tablet.

Two compounds on this page are not peptides at all, and both get filed alongside them by vendors and by search engines. Orforglipron is a small molecule taken as a daily tablet. 5-Amino-1MQ is a small-molecule enzyme inhibitor sold as a research chemical. In this market the word peptide is a marketing category rather than a chemical one, which means it tells you nothing about evidence quality or legality. The tier tells you both.

Tier 1: approved for weight management

Tier 1 means a national regulator reviewed the full dossier and issued a label. Four molecules qualify, and one of those only in China.

• Semaglutide (Wegovy, Ozempic). 14.9% mean weight loss at 68 weeks on 2.4 mg weekly in STEP 1 (n=1,961). The oral 25 mg tablet was approved for weight management on 22 December 2025 and produced 16.6% at 64 weeks under adherence in OASIS 4 (n=307). SELECT, in 17,604 people, showed a 20% reduction in major adverse cardiovascular events over a median 39.8 months at 2.4 mg.
• Tirzepatide (Zepbound, Mounjaro). SURMOUNT-1 (n=2,539, 72 weeks): 16.0% at 5 mg rising to 22.5% at 15 mg, against 2.4% on placebo. 39.7% of the 15 mg group lost at least a quarter of their body weight.
• Orforglipron (Foundayo). FDA-approved on 1 April 2026 for weight management. ATTAIN-1 at 72 weeks: 9.6% on 36 mg on the treatment-regimen estimand, 12.4% on the efficacy estimand. It is a small molecule, not a peptide, and is taken without food or water restrictions.
• Mazdutide. Approved by China's NMPA, not by FDA and not by EMA. GLORY-1 reported roughly 14.8% at 48 weeks on 6 mg in 610 Chinese adults, and a further phase 3 reported about 20% on 9 mg.

Tier 2: late-stage pipeline with real phase 3 data

These compounds have completed phase 3 trials and published results, some of them the largest weight-loss numbers ever reported for a drug. None of them can be prescribed for weight loss in the United States or the European Union as of 23 August 2026.

• Retatrutide (GIP, GLP-1 and glucagon receptor agonist). TRIUMPH-1 (n=2,339, 80 weeks): 28.3% mean loss on 12 mg, with 45.3% of participants losing 30% or more. An extension in participants with baseline BMI of 35 or above reached 30.3% at 104 weeks. Phase 3, not approved by any major regulator.
• CagriSema (cagrilintide plus semaglutide). REDEFINE-1 (n=3,417, 68 weeks): 22.7% versus 16.1% for semaglutide alone and 2.3% for placebo. On the treatment-policy estimand the same trial reads 20.4%. Not a general prescription product at the time of writing.
• Cagrilintide alone (amylin analogue). 11.8% at 68 weeks in the monotherapy arm of REDEFINE-1, below semaglutide in the same trial. Investigational.
• Survodutide (GLP-1 and glucagon dual agonist). SYNCHRONIZE-1 (n=725, 76 weeks): up to 16.6% versus 3.2% on placebo, plus a liver-fat signal, with up to 84.2% of participants achieving at least a 30% relative reduction in liver fat. Phase 3, not approved.

Tier 3: research chemicals and clinic peptides

Tier 3 is where the evidence gets thin or turns negative. Every compound below is marketed for fat loss somewhere. None has an approval for it.

• BPC-157. No weight-loss evidence of any kind. The research literature concerns tissue repair and gastrointestinal protection. It appears on weight-loss peptide lists as a marketing artefact. Its US regulatory position moved twice in 2026 and remains unsettled.
• 5-Amino-1MQ. Zero published human trials, which means no human efficacy data and no human safety data. The case for it rests entirely on rodent work: diet-induced obese rats lost about 6% of body weight over 11 days.
• AOD-9604. A 24-week phase 2b trial in 536 subjects failed to separate from placebo at any dose, and the compound was abandoned as a drug candidate in 2007. It has an unusually large tolerability database, more than 900 participants across six controlled trials with minimal adverse effects, and that tolerability record is what its marketing quotes, but the same programme showed it does not produce clinically significant fat loss in humans.
• Ipamorelin and CJC-1295. Neither is FDA-approved, and neither has been evaluated by FDA for the treatment of any disease. Human clinical evidence for the combination is limited in both scale and scope, and there is no adequate controlled weight-loss trial for either.

Evidence and legal status at a glance

Read down the columns, not across the rows. The percentages in this table come from different trials with different durations, different populations and different placebo responses, which ran anywhere from 0.5% to 3.9% weight loss on placebo alone. Durations range from 48 to 104 weeks. GLORY-1 enrolled only Chinese adults. Some numbers are efficacy estimands and some are treatment-regimen estimands, and those answer different questions. Nothing in this table is a head-to-head comparison, so a larger number is not proof of a better drug.

How to read a vendor's claims

The pattern repeats across almost every page selling these compounds, and once you can see it, the whole category reads differently.

• A percentage with no trial name, dose or duration attached. Retatrutide alone has published figures of 17.6%, 22.6%, 23.7%, 25.0%, 28.3% and 30.3%, all real, all from different trials, doses, populations or timepoints. A bare number is unsourced.
• Animal results written in the passive voice so the species disappears. Reduced fat mass and improved metabolic markers usually means mice.
• Tolerability quoted as though it were efficacy. AOD-9604 is the clearest case: a genuinely large safety database attached to a compound that failed its efficacy endpoint.
• A research-use-only disclaimer in the footer while the page copy discusses body composition and dosing. The disclaimer is a legal position taken by the seller, not a statement about what the product is being sold for.
• Manufacturing language that sounds regulatory without being it. Made in an FDA-registered facility says nothing about whether the substance inside was reviewed by anyone.
• A mechanism story doing the work evidence should be doing. A plausible pathway is where drug development starts, not where it ends. Most metabolic targets that worked in mice failed in humans.

Why not approved is not the same as banned, and not the same as safe

Unapproved means no regulator has reviewed the manufacturing, the safety database or the efficacy claim and issued a label. It does not mean the compound was assessed and rejected, and it does not mean the compound is dangerous. Retatrutide is unapproved and has the strongest phase 3 weight-loss data ever published. That gap between evidence and availability is real, and pretending otherwise is how this market sells to people.

The gap cuts the other way too. Approval is what forces a manufacturer to prove that the vial contains what the label says, in the amount the label says, sterile. FDA has found compounded GLP-1 products containing salt forms that are not equivalent to the approved active ingredient, which is direct evidence that non-standard supply chains do ship mislabelled actives. When FDA placed a batch of peptides in Category 2 in 2023, its stated concerns were immunogenicity risk, peptide-related impurities and insufficient safety data. Those concerns describe grey-market supply exactly.

There is a third category people miss. Absence of evidence is its own risk profile. 5-Amino-1MQ has never been given to a human being in a published trial, so nobody can tell you its side-effect profile, its interactions or its dose-response, because nobody has looked. That is not a clean safety record. It is a blank page.

The evidence, one row per claim

Questions people ask

Sources

1. AJMC / Lilly TRIUMPH-1
2. Novo Nordisk / NEJM
3. Boehringer Ingelheim SYNCHRONIZE-1 topline press release, 28 April 2026 (Internet Archive snapshot)
4. Secondary review of AOD-9604 trial record (verify against primary trial publication)
5. Evidence review (verify by PubMed search before publishing)
6. FDA EGRIFTA SV prescribing information
7. Innerbody (secondary; the underlying fact is absence from the FDA approved-drug list)
8. ACC / SELECT
9. STEP 1
10. Eli Lilly / NEJM
11. ClinicalTrials.gov posted results for ATTAIN-1 (NCT05869903), first posted 14 August 2026

Keep reading

• Retatrutide: Triple Agonist Phase 3 Results and Current StatusThe strongest weight-loss numbers in obesity medicine, attached to a drug you cannot legally obtain.
• Cagrilintide and CagriSema: The Amylin Route to Weight LossA genuinely different mechanism, and a case study in how obesity trial results get framed as wins or misses.
• Survodutide: GLP-1/Glucagon Dual Agonist and the Liver-Fat AngleMid-pack on weight, distinctive on liver fat. Also a lesson in why a smaller headline percentage does not mean
• Mazdutide: Approved in China, Not in the USThe compound that proves the word approved is meaningless without a jurisdiction attached.
• Orforglipron: The First Small-Molecule Oral GLP-1 for Weight ManagementLower weight loss than the injectables, and possibly the most consequential approval in the category because o
• BPC-157: What It Is, What It Is Not, and Its Unsettled Legal StatusA corrective page. The evidence base is tissue repair, the weight-loss listings are a marketing artefact, and