Not all fat loss peptides are created equal. The difference between FDA-approved compounds with robust Phase 3 data and experimental animal-model compounds is enormous. This guide ranks the most studied fat loss peptides from the most to least evidence-based, with dosage information and mechanism summaries.
Tier 1: FDA-Approved (Strongest Evidence)
Semaglutide (Wegovy/Ozempic): The current gold standard with 14.9% average weight loss in the STEP trials. GLP-1 receptor agonist. Once-weekly SubQ injection.
Tirzepatide (Zepbound/Mounjaro): Dual GLP-1/GIP agonist achieving 20-22% average weight loss in SURMOUNT trials. Currently the most effective approved weight loss drug.
Liraglutide (Saxenda): Daily GLP-1 agonist with ~8% average weight loss. Less potent than semaglutide but has the longest safety track record.
Tier 2: Clinical Trials (Strong Human Data)
Retatrutide: Triple GLP-1/GIP/glucagon agonist in Phase 3 trials. Preliminary data shows 24% weight loss at 48 weeks — potentially exceeding tirzepatide. Not yet approved.
Cagrilintide + Semaglutide (CagriSema): Amylin+GLP-1 combination in Phase 3. Amylin is a satiety hormone that works independently of GLP-1, making the combination synergistic.
Tesofensine: SNDRI (serotonin-noradrenaline-dopamine reuptake inhibitor). Phase 2 showed 12.8% weight loss — double that of approved drugs at the time. Not yet approved.
Tier 3: Research Only (Animal/Preclinical Data)
AOD-9604 / HGH Fragment 176-191: C-terminal fragment of HGH that retains fat-burning properties without IGF-1 or blood glucose effects. Strong animal data but Phase 3 trials were negative for weight loss (effective doses were much higher than expected).
5-Amino-1MQ: NNMT inhibitor that boosts metabolism and promotes fat cell apoptosis in rodent models. Human data lacking.
MOTS-C: Mitochondrial peptide that improves insulin sensitivity and exercise capacity. Fat loss in animal models, limited human data.
Important Considerations
All GLP-1/GIP agonists require concurrent resistance training to preserve lean mass — weight loss from these peptides is typically 60-70% fat and 30-40% lean mass without exercise. The experimental peptides (AOD-9604, 5-Amino-1MQ, MOTS-C) have no approved clinical use and limited human safety data.
Key Takeaways
For maximum evidence-based fat loss, semaglutide or tirzepatide are the clear leaders. For those unable to access GLP-1 drugs, GH secretagogue stacks (CJC-1295 + Ipamorelin) indirectly support fat loss through elevated GH. AOD-9604 has theoretical advantages but clinical trial results were disappointing at realistic doses.