Best Weight Loss Peptides, Compared
Ranked by clinical evidence, expected weight loss, safety profile, and real-world usability. Every score is based on published research and verified anecdotal reports.
Tirzepatide (brand names Mounjaro, Zepbound) is the most effective weight loss peptide with clinical evidence. Its dual GLP-1 + GIP mechanism produces greater weight loss than any single-target peptide — averaging **20–22% of body weight** in SURMOUNT trials at the highest doses.
- Greatest average weight loss (~20–22%)
- FDA-approved (Mounjaro, Zepbound)
- Dual mechanism targets appetite + metabolism
- Weekly injection schedule
- Strong cardiovascular benefit data
- Less long-term data than Semaglutide
- Higher cost than research alternatives
- More nausea at high doses vs Semaglutide
- Requires prescription for branded versions
Semaglutide (Ozempic, Wegovy) is the gold standard GLP-1 agonist with the most extensive real-world data. STEP trials demonstrated **15–17% average weight loss**. It also showed a 20% reduction in major cardiovascular events in the SELECT trial.
- Most clinical trial data of any weight loss peptide
- FDA-approved and widely prescribed
- Proven cardiovascular benefit (SELECT trial)
- Better tolerated than Tirzepatide at equivalent doses
- Lower weight loss ceiling vs Tirzepatide
- GLP-1 only (single mechanism)
- High cost without insurance coverage
Tesamorelin is a GHRH analog FDA-approved for HIV-associated lipodystrophy. It specifically reduces **visceral adipose tissue (belly fat)** by stimulating GH production without significantly affecting subcutaneous fat.
- Specifically targets dangerous visceral belly fat
- FDA-approved (Egrifta)
- Preserves muscle while reducing fat
- Well-studied in clinical trials
- Daily injections required
- Fat often returns when discontinued
- Less total weight loss than GLP-1 agonists
Retatrutide is a next-generation triple receptor agonist (GLP-1, GIP, glucagon) currently in Phase 3 trials. Early data shows **24% average weight loss** at 48 weeks — potentially the most effective weight loss medication ever tested. Expected FDA approval 2027-2028.
- Highest weight loss in trials (24% at 48 weeks)
- Triple mechanism (GLP-1 + GIP + glucagon)
- May preserve more muscle than dual agonists
- Weekly injection
- Promising Phase 2 data
- Not yet FDA approved (Phase 3 trials)
- Not currently available
- Long-term safety unknown
- Price expected to be high