How weight loss peptides work
Most fat-loss peptides fall into one of four categories: GLP-1 / GIP agonists like Tirzepatide and Semaglutide that slow gastric emptying and blunt appetite; triple agonistslike Retatrutide that add glucagon action for extra energy expenditure; GH fragments like AOD-9604 that target fat oxidation without affecting blood sugar; and metabolic modulatorslike 5-Amino-1MQ that raise NAD+ levels and increase metabolic rate.
These compounds are not stimulants. They work by changing the hormonal signals that drive hunger, nutrient partitioning, and fat-cell metabolism. The result is usually slower, more sustainable fat loss than crash dieting — but they require consistent dosing and often a titration schedule.
Top peptides for weight loss
GLP-1 comparison & dosing
Tirzepatide (dual GLP-1/GIP) and Semaglutide (GLP-1 only) are the most studied research options for appetite suppression. Retatrutide adds glucagon agonism and may produce the largest body-weight changes in early trials, but also carries more thermogenic side effects. All three are dosed once weekly and titrated upward slowly to limit nausea and GI upset.
For a side-by-side breakdown, see our GLP-1 comparison. To turn any vial strength into syringe units, use the dosage calculator.
Stacking strategy
A common research stack pairs a weekly GLP-1 agonist with a daily fat-mobilizing peptide. The GLP-1 handles appetite and meal size, while AOD-9604 or 5-Amino-1MQ supports lipolysis and metabolic rate. Tesamorelin can be added for visceral fat reduction, though it is primarily a GHRH analog.
Blends like CagriSema (Cagrilintide + Semaglutide) and Reta + Cagri simplify multi-mechanism dosing into a single weekly injection. These are newer and less documented, so start conservatively and track tolerance closely.
Dosing & safety basics
- Titrate slowly. GLP-1 peptides are started low and increased every 2–4 weeks to minimize nausea and GI side effects.
- Inject weekly. Most GLP-1/GIP agonists have long half-lives; once-weekly dosing is standard.
- Protect lean mass. Eat adequate protein and continue resistance training; aggressive caloric restriction plus GLP-1s can cost muscle.
- Rotate sites. Subcutaneous injections in the abdomen, thigh, or upper arm should rotate to avoid irritation.
Peptides discussed here are for research and educational purposes. GLP-1 agonists and related compounds are not FDA approved for over-the-counter weight loss in most jurisdictions. Always consult a qualified clinician, monitor bloodwork, and comply with local regulations.