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.