Written and fact-checked to our published editorial standards.Last updated 2026-08-12. Every clinical claim on this page is sourced to a named primary authority, listed at the foot of the page — see how we research, source, and correct our work.
Direct answer
What you need to know
Evidence strength: Strong
Most GLP-1 “versus” questions are not comparisons at all — they are naming confusions. A drug class, a molecule, and a brand name get set against each other as though they were three competing products. Sorting those three levels out answers most of this section at once. Where a genuine comparison does exist — and one now does — we use the trial rather than lining up two separate ones.
Key takeaways
GLP-1 is a class, semaglutide is a molecule in it, Ozempic is one brand of that molecule for one approved use.
Four molecules currently carry six approved brands. Same substance, different name, different indication.
SURMOUNT-5 is a real randomised head-to-head: tirzepatide −20.2% against semaglutide −13.7% over 72 weeks.
Everything else presented as a head-to-head is two separate trials placed side by side, which is not the same claim.
Important limitation: SURMOUNT-5 was open-label and funded by the manufacturer of the drug that won, and it compares two products at particular doses in one population. It settles that comparison and no other — there is no equivalent trial for most of the pairings people search for.
Next action: If your question is really “which of these words means what”, start with GLP-1 vs semaglutide. If it is genuinely which drug works better, go straight to semaglutide vs tirzepatide, which is built on the head-to-head.
“GLP-1” is a class of medicines. “Semaglutide” is one molecule in that class. “Ozempic” is one brand name that one manufacturer gives to that molecule for one approved use. Asking which is better is a little like asking whether a car is better than a diesel engine or than a Golf — the terms describe different levels of the same thing.
That is not the reader’s fault. The marketing for these products deliberately operates at whichever level is most flattering, and the press uses brand names as shorthand for the whole class. Separating them is the single most useful thing a comparison page can do.
The three levels, in one table
Nearly every naming question on this site resolves against this. Read it once and the four pages below stop being four separate questions.
Approved GLP-1 products in the United States, grouped by molecule. Brand and indication from the FDA labels; see sources below.
Two things fall out of the table. The same molecule appears under different brand names for different approved uses — which is why “Ozempic versus Wegovy” is a question about indication and dose, not about chemistry. And tirzepatide is not a stronger semaglutide: it acts on a second receptor, which is a difference in kind rather than degree.
Comparisons we have not written, and one we now have
This hub used to say that head-to-head efficacy comparisons were missing on purpose because nobody had run one. That is no longer true, and it was already out of date when we wrote it. SURMOUNT-5 randomised 751 adults with obesity to tirzepatide or semaglutide for 72 weeks and reported −20.2% against −13.7%. It has its own page, and the correction is logged on our corrections page.
What we still will not do is build a “winner” table out of the separate trials we log one at a time, each with the comparator it actually ran against. Those ran in different populations, for different durations, against different endpoints. Lining them up in one column implies a comparison nobody has run — which is exactly the error the existence of SURMOUNT-5 makes easier to spot, not harder.
Sources
Each source below supports specific statements on this page. We cite the strongest available authority and verify against the current version before publishing.
FDA-approved prescribing information (drug labels)DailyMed, U.S. National Library of MedicineSupports: The approved indication and brand for each molecule, which is what separates the three naming levels.
This page is general education, not medical advice. Talk to your own healthcare provider about your situation before starting, stopping, or changing any medication.