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Semaglutide vs liraglutide

Two GLP-1 receptor agonists from the same maker — Ozempic/Wegovy and Victoza/Saxenda — set side by side: the newer weekly injection against the older daily one.

Both are approved prescription medicines. Buying either without a prescription, or as grey-market powder, is a different matter — see legal status. This is a factual comparison, not medical advice.

 SemaglutideOzempic, WegovyLiraglutideVictoza, Saxenda
ReceptorGLP-1GLP-1
StatusApprovedApproved
FrequencyOnce weekly (oral daily as Rybelsus)Once daily
Half-life~1 week~13 hours
Weight brandWegovySaxenda
Diabetes brandOzempicVictoza

The short version

Same drug class, same receptor, same manufacturer — the differences are duration and strength. Liraglutide came first: a daily injection with a roughly 13-hour half-life. Semaglutide is the newer molecule, engineered to last about a week, so it is dosed weekly and has produced larger average weight loss in trials. Where semaglutide has since been overtaken on weight loss by the dual and triple agonists, liraglutide is now the older option of the class — still approved and widely used, but no longer the strongest.

Wider context: reta vs tirzepatide vs semaglutide · all GLP-1 & weight-loss peptides.

Semaglutide & liraglutide: common questions

Is semaglutide better than liraglutide for weight loss?
In the trials semaglutide has produced clearly greater average weight loss than liraglutide, and it is injected once a week rather than once a day. Liraglutide is the older, shorter-acting drug of the two. Both are approved; each entry gives the detail behind the averages.
What is the difference between Saxenda and Wegovy?
Saxenda is liraglutide, a daily injection; Wegovy is semaglutide, a weekly one. Different molecules from the same maker, both branded for weight management. (Victoza and Ozempic are the same two drugs branded for type 2 diabetes.)
Why is semaglutide once weekly but liraglutide once daily?
It is down to how long each lasts in the body: semaglutide has a half-life of about a week, liraglutide of about 13 hours. That single difference is why one is a weekly injection and the other a daily one.

Semaglutide · Liraglutide · GLP-1 hub · Legal status