Retatrutide vs Semaglutide
Last updated 13 June 2026
Quick answer
| Retatrutide | Semaglutide | |
|---|---|---|
| Signals used | Three | One (GLP-1) |
| Made by | Eli Lilly | Novo Nordisk |
| Trial stage (2026) | Phase 3 ongoing | Approved medicine |
| Brand names | Retaklik (research) | Ozempic, Wegovy |
| Top trial weight result | Up to ~24% (Phase 3) | Up to ~15% (STEP) |
| UK status | Research use only | Prescription medicine |
The simple takeaway
More signals is the headline. Semaglutide pulls one lever; retatrutide pulls three. Read how retatrutide works to see what each signal does.
What each one is
Semaglutide is made by Novo Nordisk and is already approved as Ozempic (for diabetes) and Wegovy (for weight). Retatrutide is made by Eli Lilly and is still in trials.
What the trials found
Semaglutide's STEP trials showed around 15% weight loss and led to its approval. Retatrutide's Phase 2 and Phase 3 trials showed larger average numbers. But again, these are different studies, so treat it as "promising", not a proven head-to-head win.
UK status of each
Semaglutide is a prescription medicine. Retatrutide is sold only as a research chemical. Comparing research suppliers? Start with our where-to-buy guide.
Looking at suppliers?
See where UK researchers source retatrutideCommon questions
Is semaglutide the same as Ozempic?+
Yes. Semaglutide is the drug name. Ozempic and Wegovy are brand names for it.
Does retatrutide work in a different way?+
Yes. Semaglutide uses one signal (GLP-1). Retatrutide uses three (GLP-1, GIP, glucagon). That is the core difference.
Which gives more weight loss?+
In separate trials, retatrutide showed larger average weight loss than semaglutide. But they have not been compared head-to-head, and retatrutide is still in research while semaglutide is approved.