Same class, different molecules, different results. Tick the drugs to overlay their trial curves, then read the table for what actually separates them: how much they lose, how they're dosed, who each one suits, and what to watch for.
| Wegovy (semaglutide 2.4 mg) | Zepbound (tirzepatide) | Wegovy pill (oral semaglutide 25 mg) | Saxenda (liraglutide 3.0 mg) | |
|---|---|---|---|---|
| Mechanism | GLP-1 receptor agonist | Dual GIP + GLP-1 agonist | GLP-1 agonist, tablet | GLP-1 agonist, short-acting |
| Trial average loss | −14.9% at 68 wk (STEP 1) | −15.0 / −19.5 / −20.9% at 72 wk for 5 / 10 / 15 mg (SURMOUNT-1) | −13.6% at 64 wk (OASIS 4) | −8.0% at 56 wk (SCALE) |
| Head to head | SURMOUNT-5: tirzepatide −20.2% vs semaglutide −13.7% at 72 wk | — | Semaglutide beat liraglutide −15.8% vs −6.4% (STEP 8) | |
| How it's taken | Weekly injection | Weekly injection | One tablet daily, empty stomach, 30 min before food/drink | Daily injection |
| Label titration | 0.25 → 0.5 → 1 → 1.7 → 2.4 mg, each step 4 weeks; full dose from week 17 | 2.5 → 5 → 7.5 → 10 → 12.5 → 15 mg, each step ≥4 weeks; 5 mg is the lowest maintenance dose | Stepped up monthly over about 3 months | 0.6 → 1.2 → 1.8 → 2.4 → 3.0 mg, weekly steps; full dose from week 5 |
| Extra approved uses | Cardiovascular risk reduction in people with heart disease (SELECT: 20% fewer major cardiac events); MASH | Obstructive sleep apnea in obesity | — | Adolescents 12+ |
| Tends to suit | People with existing heart disease (outcome data), people who want the most-studied option | People who need the most weight loss, BMI 35+, sleep apnea | Needle-averse people; travel; those who can keep the fasting-dose routine | Cost-driven choice (generic available), or where weekly drugs aren't covered; adolescents |
| Main GI side effects (trial rate) | Nausea 44%, diarrhea 32%, vomiting 25%, constipation 23% | 15 mg: nausea 31%, diarrhea 23%, vomiting 12%, constipation 12% | Similar pattern to the injection; nausea most common | Nausea 40%, diarrhea 21%, constipation 20%, vomiting 16% |
| Stopped for side effects | 7% (placebo 3%) | 4–6% (placebo 3%) | Similar to injection | 10% (placebo 4%) |
| Self-pay ballpark (2025–26, manufacturer direct) | Roughly $350–$500/mo via NovoCare | Roughly $350–$500/mo via LillyDirect vials | Set at launch; check NovoCare | Generic liraglutide is now the cheapest branded-class option |
Rates are from each drug's pivotal trial against placebo, so they are not perfectly comparable across trials. All four share the same boxed warning (thyroid C-cell tumours in rodents) and the same core contraindications: personal or family history of medullary thyroid carcinoma or MEN 2, and pregnancy. See side effects.
If the goal is 10% and you'd be happy there, any of the weekly options gets the average person there by week 24. If the goal is 20%+, tirzepatide is the only one whose average reaches it.
Semaglutide has published outcome data: fewer heart attacks and strokes in people who already had cardiovascular disease. Tirzepatide's outcome trial (SURPASS-CVOT) reported non-inferiority in 2025. If you have a cardiac history, this is the conversation to have.
Weekly injections have the best adherence. The pill needs a 30-minute fasting window every morning. Daily injections (Saxenda) have the highest drop-out. The best drug is the one still in the fridge at month 9.
Ozempic and Mounjaro are the same molecules as Wegovy and Zepbound, approved for type 2 diabetes with slightly different dose ranges. Prescribing them for weight alone is off-label and often not covered.
Brand-name Wegovy and Zepbound, insurance navigation, video visits. Widest medication menu.
Check eligibilityFully online, brand-name Wegovy and Ozempic after the 2026 Novo Nordisk partnership. Simplest flow.
See pricingSelf-pay vials: Zepbound via LillyDirect, Wegovy via NovoCare. Needs your own prescription.
LillyDirect