Weight Loss Peptides
GLP-1 and metabolic compounds, graded on the trial evidence behind the weight they actually move.
Weight-loss peptides are the one corner of this field with large, randomised, placebo-controlled human trials behind it. Semaglutide, tirzepatide, and retatrutide all have published phase 3 data with hard body-weight endpoints, which is why they carry the highest grades in this library. Everything else in the category is graded against that bar. Each entry below lists the dose ranges used in the published protocols, the half-life that sets the injection schedule, and links to the trials themselves.
Retatrutide
A-gradeAn investigational triple GIP/GLP-1/glucagon receptor agonist producing some of the largest average weight reductions reported for a single agent.
Exenatide
S-gradeThe first-in-class GLP-1 receptor agonist, derived from a peptide found in Gila monster saliva, sold as Byetta and Bydureon.
Liraglutide
S-gradeA once-daily GLP-1 receptor agonist, the class predecessor to semaglutide and tirzepatide, still widely prescribed under Victoza and Saxenda.
Orforglipron
S-gradeThe first oral, non-peptide GLP-1 receptor agonist pill with no food or water restrictions, FDA-approved in 2026 as Foundayo.
Semaglutide
S-gradeA GLP-1 receptor agonist that reduces appetite and improves glucose control, widely used for weight loss.
Tesamorelin
S-gradeAn FDA-approved GHRH analog known for reducing stubborn visceral fat and raising IGF-1 levels.
Tirzepatide
S-gradeA dual GIP/GLP-1 receptor agonist offering strong appetite suppression and glucose control, often more potent than semaglutide.
5-Amino-1MQ
C-gradeAn NNMT-inhibiting small molecule studied for fat loss in obese mice, no human trials have been published as of 2026.
Guides in this category
Best Peptides for Weight Loss
Compare the most effective peptides for weight loss and fat loss. Evidence-based rankings of semaglutide, tirzepatide, retatrutide, and more.
Best Peptides for Muscle Growth
Compare the best peptides for muscle growth, recovery, and body composition. Evidence-based rankings of CJC-1295, ipamorelin, and more.
Best Peptides for Beginners
The peptides most often started first, ranked by evidence quality and safety profile rather than popularity.
Semaglutide vs Tirzepatide
Semaglutide vs Tirzepatide: mechanism, dosing, evidence grade, and side effects compared side by side, with citations.
Liraglutide vs Semaglutide
Liraglutide vs Semaglutide: mechanism, dosing, evidence grade, and side effects compared side by side, with citations.
Semaglutide vs Retatrutide
Semaglutide vs Retatrutide: mechanism, dosing, evidence grade, and side effects compared side by side, with citations.
Weight Loss peptide questions
How many weight loss peptides are there?
This library covers 8 weight loss compounds, each graded from S (regulatory approval) to F (no usable evidence).
Which weight loss peptide has the strongest evidence?
Retatrutide carries the highest research grade in this category at A. An investigational triple GIP/GLP-1/glucagon receptor agonist producing some of the largest average weight reductions reported for a single agent.
What does the research grade mean?
The grade describes how well a compound has been measured in humans, not how well it works. S means regulatory approval; D means animal data only. Popularity and anecdote do not affect it.