Best Peptides for Fat Loss
There are two categories of compound sold for fat loss, and they are not close in quality. One has large randomized trials with body-composition imaging. The other has mouse data, a mechanism story, and heavy marketing. This ranking separates them.
The ranking
| # | Compound | Best human result | Evidence tier | Fat-specific data |
|---|---|---|---|---|
| 1 | Retatrutide | −25.0% body weight, 80 wk | Phase 3 topline, unpublished | Yes — T2D substudy |
| 2 | Tirzepatide | −20.9% body weight, 72 wk | Approved | Yes — DEXA substudy |
| 3 | CagriSema | −20.4% body weight, 68 wk | Phase 3 | Partial |
| 4 | Semaglutide | −14.9% body weight, 68 wk | Approved | Yes — DEXA substudy |
| 5 | Survodutide | −13.0% body weight, 76 wk | Phase 3, NEJM 2026 | Limited |
| 6 | Tesamorelin | Visceral fat reduction | Approved (HIV lipodystrophy) | Yes — visceral specific |
| 7 | 5-Amino-1MQ | None | Animal only | Mouse fat mass |
| 8 | MOTS-c | None | Animal only | Mouse adiposity |
| 9 | AOD-9604 | Not superior to placebo | Human trials, negative | Failed |
The tier that actually works
1. Retatrutide
Three receptors — GIP, GLP-1 and glucagon. The glucagon component is the differentiator: alongside appetite suppression it increases energy expenditure and drives hepatic fat mobilization, which is why the totals exceed anything before it. Phase 3 TRIUMPH-1 reported 25.0% at 80 weeks counting everyone randomised, or 28.3% assuming full adherence. The 30.3% figure quoted almost everywhere comes from a 104-week extension of 532 selected participants and is not comparable to a whole-trial number from another drug — ourranked comparison works through why. None of the TRIUMPH results has been peer-reviewed yet.
On body composition specifically, be careful with what gets claimed. A substudy did measure it — but in the Phase 2 type 2 diabetes trial (n=189), not the obesity trial, and its own conclusion was that the fat-loss index was consistent with other weight-loss treatments. So: yes, the loss came predominantly from fat, and no, retatrutide is not demonstrably more lean-sparing than its competitors. Anyone telling you otherwise is reading a substudy that does not say that.
Not approved; research chemical only. Dosing details are in ourretatrutide dosage guide.
Retatrutide (RTA) — 10 mg — American Peptides
Batch-tested with HPLC and mass spectrometry, COA provided. Not FDA approved — research use only.
We may earn a commission if you buy through this link (at no extra cost to you). Sold for research purposes only.
2. Tirzepatide
Approved, extensively studied, and 20.9% body weight reduction at 72 weeks in SURMOUNT-1. Its DEXA substudy showed fat mass fell about three times as much as lean mass — a favorable ratio, though lean loss was not zero. If you want the strongest evidence with a legal prescription pathway, this is the answer.
3. CagriSema
Cagrilintide is a long-acting amylin analogue, and amylin signals satiety through a pathway independent of GLP-1. Pairing the two produced 20.4% at 68 weeks in REDEFINE 1. The interesting principle here is mechanism diversity: two different satiety systems add up better than pushing one harder.
4. Semaglutide
14.9% at 68 weeks — less than the newer agents, but with the deepest safety database and cardiovascular outcome data from SELECT that nothing else on this list has.
5. Survodutide
GLP-1 plus glucagon, and no longer a Phase 2 compound: its Phase 3 trial SYNCHRONIZE-1 was published in the New England Journal of Medicine in June 2026, reporting 13.0% at 76 weeks in 725 adults counting everyone randomised, or 16.6% assuming full adherence. There is additional signal in liver fat. Body-composition data specifically remains thin.
6. Tesamorelin — the specialist
Worth separating from the rest. Tesamorelin is a GHRH analogue approved specifically for reducing excess visceral adipose tissue in HIV-associated lipodystrophy, and its trials showed roughly 15–18% visceral fat reduction. It does not produce large total weight loss — it redistributes where fat is lost, targeting the visceral compartment. That is a narrow but genuinely evidence-backed niche.
The tier that does not hold up
7. 5-Amino-1MQ
Inhibits NNMT, an enzyme involved in adipocyte metabolism, and reduced fat mass in obese mice without changing food intake. That is a genuinely interesting mechanism, and it is the entire evidence base — there is no human trial. It is sold aggressively as an oral fat-loss compound on the strength of rodent results.
8. MOTS-c
Prevented diet-induced obesity and improved insulin sensitivity in mice, and human observational data shows levels rise with exercise. No human trial for fat loss exists. Mechanistically among the most interesting compounds in this space; evidentially not ready to rank above the GLP-1 class. Details in our MOTS-c guide.
9. AOD-9604 — the cautionary tale
A fragment of human growth hormone (residues 176-191) developed specifically as an anti-obesity agent. It reached human trials, the obesity program was discontinued in 2007, and no trial result showing an advantage over placebo was ever published in a peer-reviewed journal — the phase 2 data exists only in company disclosures. That is worth stating precisely: the evidence for it is not weak, it is absent. It is still marketed as a fat-loss peptide today, which tells you how little market demand depends on results.
What the body-composition data actually shows
This is the part that separates a fat-loss question from a weight-loss question, and the honest answer is less flattering than the marketing.
| Compound | Measurement | What it found |
|---|---|---|
| Tirzepatide | DEXA substudy, SURMOUNT-1 | Fat mass fell roughly three times as much as lean mass — the best-documented ratio in the class |
| Semaglutide | DEXA substudy, STEP-1 | Loss predominantly fat, with lean loss broadly proportional to what a calorie deficit produces |
| Retatrutide | Substudy in the phase 2 T2D trial, n=189 | Predominantly fat, with a fat-loss index the authors called consistent with other weight-loss treatments |
| Tesamorelin | CT-measured visceral adipose tissue | 15–18% visceral fat reduction specifically — the only compound here with a compartment-specific result |
Lean mass: the part nobody advertises
Rapid weight loss costs lean tissue. In GLP-1 trials, roughly 20–40% of total weight lost was lean mass depending on the study and population — which is broadly what happens with any large calorie deficit, not a special property of the drugs. Trial protocols and clinical practice address it the same way: resistance training and adequate protein intake. No peptide has been shown to substitute for either, and none of the compounds on this page is demonstrably more lean-sparing than the others. Anyone claiming otherwise is reading a substudy that does not say it.
What happens when you stop
Regain is the norm. The STEP-1 withdrawal extension found participants regained about two-thirds of lost weight within a year of stopping semaglutide, with cardiometabolic improvements reverting alongside. These compounds manage a condition while they are being taken; none of them resolve it.
The full metabolic research line — American Peptides
Retatrutide, tirzepatide, semaglutide and cagrilintide — all with batch certificates of analysis. Coupon below for 10% off.
We may earn a commission if you buy through this link (at no extra cost to you). Sold for research purposes only.
Frequently asked questions
What is the best peptide for fat loss?
By published trial data, retatrutide. Comparing like with like — the analysis that counts every participant randomised — Phase 3 TRIUMPH-1 reported 25.0% mean body-weight reduction at 80 weeks, against 20.9% for tirzepatide. A phase 2 substudy in type 2 diabetes confirmed the loss came predominantly from fat rather than lean tissue, though at a ratio the authors called consistent with other weight-loss treatments, not better. Tirzepatide is the strongest option that is actually approved.
Do peptides burn fat without diet changes?
No. The GLP-1 class works largely by reducing appetite and food intake, so the fat loss is the result of a calorie deficit the drug makes easier to sustain. The compound marketed as a direct fat burner — AOD-9604, the hGH 176-191 fragment — was taken into human trials and its obesity program was discontinued without a published result showing benefit over placebo.
Which peptides preserve muscle while losing fat?
No peptide reliably prevents lean mass loss during a deficit. Growth hormone secretagogues such as CJC-1295 and ipamorelin are used with that intent, but the evidence for muscle preservation during weight loss is weak. Resistance training and adequate protein have far better support.
Can you combine fat loss peptides?
Combinations exist in trials — CagriSema pairs an amylin analogue with semaglutide, and produced better results than either alone. Stacking multiple unapproved research compounds is a different situation entirely, with no safety data behind the combination.
Sources
- Jastreboff AM et al. Triple–Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. New England Journal of Medicine, 2023;389(6):514–526. PubMed
- Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). New England Journal of Medicine, 2022;387(3):205–216. PubMed
- Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP-1). New England Journal of Medicine, 2021;384(11):989–1002. PubMed
- le Roux CW, Wharton S, Startseva E, et al. Survodutide Once Weekly for the Treatment of Adults with Obesity (SYNCHRONIZE-1). New England Journal of Medicine, published online 7 June 2026. PubMed · doi:10.1056/NEJMoa2600751
- Garvey WT et al. Coadministered Cagrilintide and Semaglutide in Adults with Overweight or Obesity (REDEFINE 1). New England Journal of Medicine, 2025;393(7):635–647. PubMed
- Eli Lilly. TRIUMPH-1 Phase 3 topline results, 21 May 2026. Company announcement. Not peer-reviewed.
- Falutz J et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. New England Journal of Medicine, 2007;357(23):2359–70. PubMed
- Falutz J et al. Effects of tesamorelin in HIV-infected patients with abdominal fat accumulation: a randomized placebo-controlled trial with a safety extension. JAIDS, 2010;53(3):311–22. PubMed
- Neelakantan H et al. Selective and membrane-permeable small molecule inhibitors of nicotinamide N-methyltransferase reverse high fat diet-induced obesity in mice. Biochemical Pharmacology, 2018;147:141–152. PubMed
- Heffernan M et al. The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and beta(3)-AR knock-out mice. Endocrinology, 2001;142(12):5182–9. PubMed
- Wilding J. AOD-9604 Metabolic (review of the clinical program). Current Opinion in Investigational Drugs, 2004;5(4):436–40. PubMed — note that no human AOD-9604 trial result is indexed in PubMed; the phase 2 obesity data exists only in company disclosures.
Related guides
- Best peptides for weight loss
- Compare retatrutide research suppliers
- MOTS-c peptide guide
- Are peptides safe?