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Retatrutide and Semaglutide Together: What Is Known

Retatrutide and Semaglutide taken together: what each one is, how each is regulated, and what is known about combining them.

Medically reviewed by Juan Pablo Frías, MD · · DisclosureUpdated
GLP-1 / GIP / glucagon triple agonistInvestigational · phase 3RetatrutideInvestigational triple GIP, GLP-1 and glucagon receptor agonist, not FDA-approved; a phase 3 TRIUMPH trial reported mean weight change of -25.0% at the 12-mg dose versus -3.9% with placebo.[1]GLP-1 & metabolicGLP-1 agonistFDA approved (Ozempic, Wegovy, Rybelsus)SemaglutideFDA-approved GLP-1 receptor agonist (Ozempic, Wegovy, Rybelsus); in a 68-week trial in adults with obesity, mean weight change was -14.9% versus -2.4% with placebo.[15]GLP-1 & metabolic
Interaction notes

Timing, interactions and safety

Evidence for the combination

No studies tested these together (PubMed search: 90 results, 2 Oct 2026).

Retatrutide is not FDA approved, and we have no sourced data on combining it with Semaglutide.
Each component

Side by side

Showing 9 of 13 fields where the two differ. Category, PCAC vote, Jul 2026, Evidence strength, Named in FDA warning letters, 2026 are the same or both unknown.

FieldRetatrutideSemaglutide
ClassGLP-1 / GIP / glucagon triple agonistGLP-1 agonist
Also calledreta, GLP-3, LY3437943sema, Ozempic, Wegovy, Rybelsus, Wegovy pill
FDA statusInvestigational · phase 3FDA approved (Ozempic, Wegovy, Rybelsus)
WADAProhibited by WADA (S0)Retatrutide is not named, and GLP-1/amylin class agonists are not listed. But it is an investigational drug with no approval in the sources we reviewed, and S0 prohibits drugs under clinical development that no authority has approved. If it is approved somewhere this would change.Not on the WADA Prohibited ListGLP-1 and GIP agonists are not named anywhere on the 2026 list. This one is an approved medicine, so the catch-all S0 (which only covers drugs with no approval anywhere) does not apply to it.
Half-lifeapproximately 6 dayssubcutaneous · Lancet 2022, PMID 36354040approximately 1 weeksubcutaneous · FDA label (Ozempic)
Human studies we summarised11 human (11 randomized or controlled) of 16 summarised23 human (19 randomized or controlled) of 27 summarised
Typical study doses
Vial sizes sold5 mg, 10 mg, 12 mg, 15 mg, 20 mg, 24 mg, 30 mg, 36 mg, 40 mg, 50 mg, 60 mg2 mg, 3 mg, 5 mg, 10 mg, 15 mg, 20 mg, 30 mg
US searches per month823,000 · +172% searches368,000 · −38% searches
Related tools

Retatrutide vs Semaglutide

Choosing between the two rather than combining them? The comparison lines them up field by field.

Open the comparison
ComparisonRetatrutide vs Semaglutide

What people search

  • retatrutide and semaglutide together140/mo
  • semaglutide retatrutide50/mo
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  • retatrutide with semaglutide30/mo
  • ozempic retatrutide30/mo

US monthly searches, Google Keyword Planner, Oct 2026. Shown so you can see which questions this page answers.

Sources

  1. 1Retatrutide phase 3 TRIUMPH-1 results publishedNEJM (PubMed 42814954) · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  2. 2FDA warning letters to five research-peptide sellersFDA warning letter (NuScience Peptides; 1 of 5) · 2026fda.govAccessed 2 Oct 2026
  3. 3Eli Lilly sues six retatrutide sellersEli Lilly (press release) · 2026investor.lilly.comAccessed 2 Oct 2026
  4. 4FDA proposes excluding semaglutide, tirzepatide and liraglutide from the 503B bulks listFDA · 2026fda.govAccessed 2 Oct 2026
  5. 5Seven FDA warning letters to online sellers of GLP-1 productsFDA warning letter (Gram Peptides; 1 of 7) · 2026fda.govAccessed 2 Oct 2026
  6. 6World Anti-Doping Code International Standard Prohibited List 2026World Anti-Doping Agency · 2026wada-ama.orgAccessed 2 Oct 2026
  7. 7LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist in people with type 2 diabetes: a phase 1b, multicentre, double-blind, placebo-controlled, randomised, multiple-ascending dose trial.Lancet (London, England) · 2022PMID 36354040Accessed 2 Oct 2026
  8. 8Retatrutide-Associated Improvements in Cardiovascular Risk Biomarkers in Adults With Obesity With or Without Type 2 Diabetes.Diabetes, obesity & metabolism · 2026PMID 42608321Accessed 2 Oct 2026
  9. 9Effects of retatrutide on body composition in people with type 2 diabetes: a substudy of a phase 2, double-blind, parallel-group, placebo-controlled, randomised trial.The lancet. Diabetes & endocrinology · 2025PMID 40609566Accessed 2 Oct 2026
  10. 10These highlights do not include all the information needed to use OZEMPIC ® safely and effectively. See full prescribing information for OZEMPIC. OZEMPIC (semaglutide) injection, for subcutaneous use FDA label (Ozempic), DailyMed · current labeldailymed.nlm.nih.govAccessed 2 Oct 2026
  11. 11Efficacy and safety of oral semaglutide 14 mg (flexible dose) in early-stage symptomatic Alzheimer's disease (evoke and evoke+): two phase 3, randomised, placebo-controlled trials.Lancet (London, England) · 2026PMID 41865758Accessed 2 Oct 2026
  12. 12Phase 3 Trial of Semaglutide in Metabolic Dysfunction-Associated Steatohepatitis.The New England journal of medicine · 2025PMID 40305708Accessed 2 Oct 2026
  13. 13Oral Semaglutide at a Dose of 25 mg in Adults with Overweight or Obesity.The New England journal of medicine · 2025PMID 40934115Accessed 2 Oct 2026
  14. 14PubMed search: (retatrutide[tiab] OR LY3437943[tiab]) AND (semaglutide[tiab] OR Ozempic[tiab] OR Wegovy[tiab] OR Rybelsus[tiab] OR NN9535[tiab])PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  15. 15Once-Weekly Semaglutide in Adults with Overweight or Obesity.The New England journal of medicine · 2021PMID 33567185Accessed 2 Oct 2026

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