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Comparison

Retatrutide vs Semaglutide

Both are GLP-1 & incretins, so the meaningful differences are in kinetics, evidence and regulatory status.

On published evidence alone, Semaglutide is the better documented of the two (regulator approved). That is a statement about the state of the literature, not a recommendation.

Retatrutide Semaglutide
Class GLP-1 & incretins GLP-1 & incretins
Evidence Clinical trials Regulator approved
Human trials ~8 ~90
Half-life ~6 days ~7 days
Reported range 1-12 mg 250 mcg - 2.4 mg
Frequency Once weekly (trial protocols) Once weekly, titrated over 16+ weeks
Routes Subcutaneous Subcutaneous, Oral
FDA approved No Yes
Research use only Yes No
Banned in sport No No
Studied for Investigational obesity treatment, Type 2 diabetes research, NAFLD research Type 2 diabetes, Chronic weight management, Cardiovascular risk reduction
Reported side effects Nausea, Vomiting, Diarrhoea, Increased heart rate, Constipation Nausea, Vomiting, Diarrhoea, Constipation, Abdominal pain, Injection-site reactions

Retatrutide

Retatrutide adds glucagon receptor agonism to the GIP and GLP-1 activity of tirzepatide. Glucagon receptor signalling raises energy expenditure and promotes hepatic fat oxidation, which is the proposed reason phase II results exceeded what incretin action alone produces. The phase II trial reported mean weight reduction of around 24% at 48 weeks on the highest dose. As of 2026 it is in Phase 3 (the TRIUMPH program) and is not FDA approved, so no regulatory conclusion on efficacy or safety has been reached.

Semaglutide

Semaglutide is a GLP-1 analog with roughly 94% homology to native GLP-1, modified by substituting alpha-aminoisobutyric acid at position 8 to resist DPP-4 cleavage and by attaching a C18 fatty diacid chain that binds albumin. Together these give a half-life of about a week, allowing once-weekly dosing. It lowers blood glucose through glucose-dependent insulin secretion and glucagon suppression, slows gastric emptying, and acts on hypothalamic appetite centres to reduce energy intake. The STEP trial programme reported mean weight reductions near 15% of body weight at 68 weeks on 2.4 mg weekly.

Retatrutide vs Semaglutide: common questions

What is the difference between Retatrutide and Semaglutide?

Both are GLP-1 & incretins. Retatrutide: An investigational triple agonist at GIP, GLP-1 and glucagon receptors, in Phase 3 trials and not FDA approved. Semaglutide: A long-acting GLP-1 receptor agonist and the compound that reset expectations for pharmacological weight loss.

Which has stronger evidence, Retatrutide or Semaglutide?

Semaglutide has the stronger evidence base (regulator approved, about 90 human studies) compared with Retatrutide (clinical trials).

Are Retatrutide and Semaglutide FDA approved?

Only Semaglutide is FDA approved (Type 2 diabetes mellitus (Ozempic, Rybelsus); Chronic weight management (Wegovy); Cardiovascular risk reduction in established CVD with overweight or obesity; Reducing the risk of kidney disease progression and cardiovascular death in adults with type 2 diabetes and chronic kidney disease (Ozempic, January 2025); Noncirrhotic MASH with moderate to advanced liver fibrosis in adults (Wegovy, accelerated approval August 2025)). Retatrutide is not approved for any indication.

References

Regulatory and primary sources

  1. PubChem compound record (CID 171390338) ↗ · structure, identifiers, synonyms
  2. FDA: Unapproved drugs and "research use only" products ↗ · regulatory status of non-approved products
  3. PubChem compound record (CID 56843331) ↗ · structure, identifiers, synonyms
  4. DailyMed: FDA-approved labeling for Semaglutide ↗ · indications, dosing, warnings as approved
  5. FDA Drugs@FDA database ↗ · approval history
  6. CAS Registry Number 910463-68-2 ↗ · chemical identity

Published literature

  1. Jastreboff AM, Kaplan LM, Frías JP, et al.. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial.N Engl J Med 2023.PubMed 37366315 · doi:10.1056/NEJMoa2301972
  2. Sanyal AJ, Kaplan LM, Frias JP, et al.. Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial.Nat Med 2024.PubMed 38858523 · doi:10.1038/s41591-024-03018-2
  3. Misra S, Narayan RK, Kaur M. Efficacy and safety of retatrutide for the treatment of obesity: a systematic review of clinical trials.J Basic Clin Physiol Pharmacol 2025.PubMed 40728138 · doi:10.1515/jbcpp-2025-0113
  4. Katsi V, Koutsopoulos G, Fragoulis C, et al.. Retatrutide-A Game Changer in Obesity Pharmacotherapy.Biomolecules 2025.PubMed 40563436 · doi:10.3390/biom15060796
  5. Locatelli JC, Costa JG, Haynes A, et al.. Incretin-Based Weight Loss Pharmacotherapy: Can Resistance Exercise Optimize Changes in Body Composition?.Diabetes Care 2024.PubMed 38687506 · doi:10.2337/dci23-0100
  6. Moiz A, Filion KB, Toutounchi H, et al.. Efficacy and Safety of Glucagon-Like Peptide-1 Receptor Agonists for Weight Loss Among Adults Without Diabetes : A Systematic Review of Randomized Controlled Trials.Ann Intern Med 2025.PubMed 39761578 · doi:10.7326/ANNALS-24-01590
  7. Panou T, Gouveri E, Popovic DS, et al.. Retatrutide in type 2 diabetes mellitus and obesity: an overview.Expert Rev Clin Pharmacol 2026.PubMed 41785010 · doi:10.1080/17512433.2026.2642415
  8. Drucker DJ. Efficacy and Safety of GLP-1 Medicines for Type 2 Diabetes and Obesity.Diabetes Care 2024.PubMed 38843460 · doi:10.2337/dci24-0003
  9. Wilding JPH, Batterham RL, Davies M, et al.. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension.Diabetes Obes Metab 2022.PubMed 35441470 · doi:10.1111/dom.14725
  10. Rubino DM, Greenway FL, Khalid U, et al.. Effect of Weekly Subcutaneous Semaglutide vs Daily Liraglutide on Body Weight in Adults With Overweight or Obesity Without Diabetes: The STEP 8 Randomized Clinical Trial.JAMA 2022.PubMed 35015037 · doi:10.1001/jama.2021.23619
  11. Wilding JPH, Batterham RL, Calanna S, et al.. Once-Weekly Semaglutide in Adults with Overweight or Obesity.N Engl J Med 2021.PubMed 33567185 · doi:10.1056/NEJMoa2032183
  12. Rubino D, Abrahamsson N, Davies M, et al.. Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance in Adults With Overweight or Obesity: The STEP 4 Randomized Clinical Trial.JAMA 2021.PubMed 33755728 · doi:10.1001/jama.2021.3224
  13. Aronne LJ, Horn DB, le Roux CW, et al.. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity.N Engl J Med 2025.PubMed 40353578 · doi:10.1056/NEJMoa2416394
  14. Wharton S, Freitas P, Hjelmesæth J, et al.. Once-weekly semaglutide 7·2 mg in adults with obesity (STEP UP): a randomised, controlled, phase 3b trial.Lancet Diabetes Endocrinol 2025.PubMed 40961952 · doi:10.1016/S2213-8587(25)00226-8
  15. Lincoff AM, Brown-Frandsen K, Colhoun HM, et al.. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes.N Engl J Med 2023.PubMed 37952131 · doi:10.1056/NEJMoa2307563
  16. Frías JP, Davies MJ, Rosenstock J, et al.. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes.N Engl J Med 2021.PubMed 34170647 · doi:10.1056/NEJMoa2107519

Literature retrieved from PubMed on October 16, 2026, favouring human studies and reviews. Numbered markers in the text show which paper supports which statement; uncited entries are background reading.

Read this first This page compares published reference data. It is not medical advice and not a recommendation to use either compound. Several compounds documented on this site are not approved for human use.