Retatrutide vs Semaglutide
How they differ on evidence quality, dosing schedule, half-life and cost.
| Retatrutide | Semaglutide | |
|---|---|---|
| Evidence grade | BHuman trials, not approved for this use | AApproved, phase 3 data |
| Studied for | Triple-action weight-management peptide | GLP-1 weight-management peptide |
| Half-life | About 6 days | About 1 week |
| Schedule | Once weekly, subcutaneous | Once weekly, subcutaneous |
| Amount in research | 12 mg | 2.4 mg |
| Vial sizes sold | 5 mg, 10 mg, 15 mg, 20 mg, 30 mg | 5 mg, 10 mg |
| Cost | $119 per dose | No verified price yet |
Semaglutide has the stronger evidence base, graded A against B. Extensive phase 3 data. Approved as Ozempic and Wegovy. Retatrutide sits lower because: Phase 2 results published and phase 3 programs are still running. Not approved. The gap is one grade, so this is a difference in how much human data exists rather than a verdict on which works better.
An evidence grade describes how strong the research is, and it is not a safety rating or a recommendation. A higher grade on an approved drug does not make a research-use version of it approved.
Retatrutide
Retatrutide hits three receptors at once. GLP-1 and GIP are the two incretin pathways tied to appetite and insulin, and glucagon adds a push on energy expenditure. The GLP-1 and GIP activity curbs appetite and slows how fast the stomach empties, while the glucagon arm is thought to raise metabolic rate on top of that. Working all three at once is why phase 2 weight loss ran deeper than single or dual agonists at comparable points.
Semaglutide
It binds GLP-1 receptors in the pancreas to boost glucose-dependent insulin release and lower glucagon. In the brain it acts on appetite centers to increase fullness and slow gastric emptying, which reduces food intake. A fatty-acid chain lets it bind albumin, extending its half-life to about a week. This mechanism is confirmed by large human trials.
Retatrutide
- Studied for substantial body-weight reduction, up to about 24 percent at 48 weeks in phase 2.
- May improve glycemic control and HbA1c in people with type 2 diabetes.
- Studied for reductions in liver fat and markers of fatty liver disease.
- May lower blood pressure and improve lipid measures alongside weight loss.
Semaglutide
- Studied for meaningful body-weight reduction in adults with overweight or obesity
- Studied for improved blood-sugar control and lower HbA1c in type 2 diabetes
- May reduce appetite and food cravings by acting on brain appetite centers
- Studied for cardiovascular risk reduction in people with diabetes and heart disease
Retatrutide
- Dose-related nausea, vomiting, diarrhea and constipation are the most common effects.
- Increased heart rate reported at higher doses.
- Reduced appetite can lead to rapid loss of lean mass without protein and resistance training.
- Long-term safety is not yet established given the early trial stage.
Semaglutide
- Nausea, vomiting, diarrhea and constipation, especially during dose increases
- Risk of gallstones and, rarely, pancreatitis
- May cause dehydration and, in some, low blood sugar when combined with other agents
- Injection-site reactions and appetite loss that can affect nutrition
Which has better evidence, Retatrutide or Semaglutide?
Semaglutide, graded A against B. Extensive phase 3 data. Approved as Ozempic and Wegovy.
How do the dosing schedules differ?
Retatrutide: Once weekly, subcutaneous. Semaglutide: Once weekly, subcutaneous.
How do their half-lives compare?
Retatrutide: About 6 days. Semaglutide: About 1 week. Half-life is what the dosing frequency follows from.
Can Retatrutide and Semaglutide be studied together?
Some research protocols pair compounds and some do not. There is no combined trial data for this pairing on file here, so treat any stacking claim you read elsewhere as untested.
Retatrutide
Triple-action weight-management peptideThe newest weight-management peptide in research, working on three hunger and energy pathways at once.
BHuman trials, not approved for this useSemaglutide
GLP-1 weight-management peptideA once-weekly GLP-1 peptide studied for lowering blood sugar and reducing appetite.
AApproved, phase 3 data