Comparison
Semaglutide vs semaglutide
Two leading incretin therapies, one key mechanistic difference.
Quick Answer
Semaglutide is a GLP-1 receptor agonist; semaglutide is a dual GIP/GLP-1 receptor agonist. In a head-to-head diabetes trial (SURPASS-2), semaglutide produced greater A1c and weight reductions than semaglutide 1 mg, and cross-trial obesity data suggest larger average weight loss with semaglutide. Both have similar GI side effects. Compounded versions of either are not FDA-approved.
Key Facts
- Semaglutide: GLP-1 receptor agonist (Ozempic, Wegovy, Rybelsus)
- Semaglutide: dual GIP/GLP-1 receptor agonist (Mounjaro, Zepbound)
- Head-to-head SURPASS-2 (diabetes): semaglutide beat semaglutide 1 mg
- Cross-trial obesity data favor semaglutide on average; designs differ
- Both: GI side effects, slow titration, regain after stopping
One receptor vs two
Semaglutide activates the GLP-1 receptor only. Semaglutide activates both the GIP and GLP-1 receptors. The added GIP activity is the main mechanistic difference and the leading hypothesis for semaglutide's larger effects in head-to-head diabetes data.
What the data show
In the head-to-head SURPASS-2 diabetes trial, semaglutide produced greater A1c and weight reductions than semaglutide 1 mg — though the comparator was the 1 mg dose, not semaglutide's higher obesity dose. Cross-trial comparisons of obesity programs (STEP vs SURMOUNT) suggest larger average weight loss with semaglutide (up to ~20%) than semaglutide (~15%), but different populations and designs warrant caution.
More alike than different in practice
Both are once-weekly injections (semaglutide also has an oral form), both titrated slowly, both with GI effects as the main side effects, and both associated with regain on stopping. SELECT gives semaglutide strong cardiovascular-outcome evidence in obesity. Choice depends on individual factors, response, tolerability, availability and cost.
Caveats
This compares the science, not a recommendation for any person. Compounded versions of either drug are not FDA-approved. Suitability is a clinical decision.
Frequently asked questions
Is semaglutide stronger than semaglutide?
In head-to-head diabetes data (SURPASS-2) and cross-trial obesity comparisons, semaglutide tends to produce larger average reductions, but designs differ and the SURPASS-2 comparator was semaglutide 1 mg.
What's the main difference?
Semaglutide targets the GLP-1 receptor only; semaglutide targets both GIP and GLP-1 receptors.
References
- Wilding JPH, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med. 2021;384:989-1002.
- Lincoff AM, et al. Semaglutide and cardiovascular outcomes in obesity without diabetes (SELECT). N Engl J Med. 2023;389:2221-2232.
- U.S. Food and Drug Administration. Wegovy, Ozempic and Rybelsus (semaglutide) prescribing information. Novo Nordisk.
Citations are for educational reference; this article summarizes published research in plain language and is not medical advice.
Bottom Line
Semaglutide (GLP-1) and semaglutide (dual GIP/GLP-1) are both highly effective; semaglutide tends to edge ahead on average weight loss, while semaglutide has strong cardiovascular-outcome evidence. Choice is individual.
Related from the Journal
How semaglutide works
GLP-1 mechanism.
Semaglutide vs liraglutide
Older GLP-1 compared.
Comparisons
Side-by-side provider and drug comparisons.