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Weight Loss & Metabolic Peptides: Mechanism Comparison
The table below compares the receptor targets, half-lives, clinical trial outcomes, and practical considerations for the most studied weight loss & metabolic peptides as of 2026. Semaglutide GLP-1 receptor agonist ~7 days 14.9% at 68 weeks (STEP-1) Slows gastr
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This page preserves a source comparison for education. It does not add a rating, recommendation or clinical judgment.
- The table below compares the receptor targets, half-lives, clinical trial outcomes, and practical considerations for the most studied weight loss & metabolic peptides as of 2026.
- Semaglutide
- GLP-1 receptor agonist
- ~7 days
- 14.9% at 68 weeks (STEP-1)
- Slows gastric emptying; activates hypothalamic POMC neurons
- FDA-approved (Wegovy 2.4mg weekly)
- Tirzepatide
- Dual GIP/GLP-1 agonist
- ~5 days
- 20.9% at 72 weeks (SURMOUNT-1)
- GIP agonism enhances insulin secretion and shifts adipose metabolism when paired with GLP-1
- FDA-approved (Zepbound 15mg weekly)
- Retatrutide
- Triple GLP-1/GIP/glucagon agonist
- ~6 days
- 24% at 48 weeks (Phase 2)
- Glucagon receptor activation increases energy expenditure and hepatic fat oxidation
- Phase 3 trials ongoing
- Liraglutide
- ~13 hours
- 8% at 56 weeks (SCALE)
- Daily injection requirement limits adherence; shorter half-life produces less stable appetite suppression
- FDA-approved (Saxenda 3.0mg daily)
- Tesofensine
- Triple reuptake inhibitor (dopamine, norepinephrine, serotonin)
- ~8 days
- 10.6% at 24 weeks
- Stimulant-like mechanism; increases energy expenditure through thermogenesis
- Not FDA-approved; research use
- AOD9604
- Growth hormone fragment (hGH 176-191)
- ~2 hours
- Limited clinical data
- Proposed lipolytic effect without insulin resistance or hyperglycemia risk; lacks robust RCT support
- Research compound only
- Professional Assessment: Tirzepatide and retatrutide represent the current ceiling for pharmacological weight reduction—dual and triple agonism produces significantly greater weight loss than GLP-1 monotherapy without proportional increases in adverse events. For research applications requiring once-weekly dosing and maximal efficacy, tirzepatide is the current standard. Retatrutide may surpass it pending Phase 3 results, but its glucagon agonist component raises theoretical concerns about hepatic glucose output in non-diabetic populations that require longer-term safety data.