Best Peptides for Fat Loss in 2026: An Evidence-Based Ranking
Semaglutide, Tirzepatide, Retatrutide, and AOD-9604 compared — mechanism, published weight-loss data, dosing ranges, side effects, and cost per month.
Every month a new peptide gets called the 'next Ozempic' on TikTok. Most of the noise is not backed by trials. This is a plain-language ranking of the four peptides with the strongest published fat-loss evidence as of mid-2026, ordered by average weight loss in phase 3 trials.
The ranking
| Peptide | Avg. loss (72 wk) | Typical research dose | Cost/mo* |
|---|---|---|---|
| Retatrutide | ~24% body weight | 2–12 mg weekly | $180–$280 |
| Tirzepatide | ~21% body weight | 2.5–15 mg weekly | $120–$200 |
| Semaglutide | ~15% body weight | 0.25–2.4 mg weekly | $90–$160 |
| AOD-9604 | Marginal in humans | 250–500 mcg daily | $40–$80 |
*Cost is a rough gray-market estimate. Insurance-covered prescription pricing is different.
1. Retatrutide — highest ceiling, least long-term safety data
Retatrutide is a triple agonist (GLP-1, GIP, glucagon). In Eli Lilly's phase 2 trial (Jastreboff et al., NEJM 2023), participants at the 12 mg weekly dose lost roughly 24.2% of body weight over 48 weeks — the largest loss ever recorded from a single molecule in an obesity trial. Phase 3 results are pending.
Trade-offs: aggressive titration is required (nausea, vomiting are common in the first 8 weeks), and there is no multi-year safety data. Cost on the research market runs highest of the group.
2. Tirzepatide — best evidence-to-cost ratio
Tirzepatide (GLP-1 + GIP dual agonist) delivered ~21% mean weight loss at 15 mg weekly in SURMOUNT-1 (Jastreboff et al., NEJM 2022). It has FDA approval as Zepbound for chronic weight management. Gray-market pricing is roughly 40% cheaper than retatrutide with about 87% of the effect.
3. Semaglutide — the baseline everyone should compare against
Semaglutide is the most studied GLP-1 in this list. STEP-1 (Wilding et al., NEJM 2021) reported ~14.9% weight loss over 68 weeks at 2.4 mg weekly. It is the cheapest of the three GLP-1 class options and has the most cardiovascular outcome data (SELECT trial, 2023).
4. AOD-9604 — mostly hype
AOD-9604 is a fragment of human growth hormone marketed as a fat burner. Early rodent studies were promising; human trials (Heffernan et al., 2001; Ng et al., 2006) failed to show meaningful weight loss versus placebo. It is cheap and low-risk but is not a serious contender.
How to choose
- First-time user: semaglutide. Most data, cheapest, gentlest titration.
- Plateaued on semaglutide: switch to tirzepatide before stacking anything.
- Willing to accept unknown long-term risk for maximum result: retatrutide.
- Looking for a stimulant-free fat burner: skip peptides entirely; the human data is not there.
References
- Jastreboff AM et al. Triple–Hormone-Receptor Agonist Retatrutide for Obesity. NEJM 2023.
- Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity. NEJM 2022.
- Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. NEJM 2021.
- Lincoff AM et al. Semaglutide and Cardiovascular Outcomes (SELECT). NEJM 2023.