How Wegovy and Saxenda work — mechanism comparison
Wegovy (semaglutide) and Saxenda (liraglutide) belong to overlapping but distinct drug classes. Both work via the incretin (gut-hormone) pathway, but they have different molecular targets:
- Wegovy (semaglutide) — GLP-1 receptor agonist
- Saxenda (liraglutide) — GLP-1 receptor agonist
This mechanistic difference matters because it determines: efficacy (how much weight loss / blood-sugar control you can expect), side-effect profile, dosing schedule, and which patients may benefit most. Read more in our Wegovy mechanism guide and Saxenda mechanism guide.
Efficacy head-to-head
In their respective pivotal trials, mean body-weight reduction reached:
- Wegovy: 14.9% at 68 weeks (trial: STEP-1)
- Saxenda: 8% at 56 weeks (trial: SCALE)
Wegovy produced 6.9 percentage points more weight loss than Saxenda in their separate trials, which were not run head-to-head and enrolled different populations. Real-world differences may be smaller, and individual variability is large.
Side-by-side radar: Wegovy vs Saxenda
Editorial scoring across 5 dimensions, overlaid. Higher area = better overall fit.
| Axis | Wegovy | Saxenda |
|---|---|---|
| Efficacy | 8 | 6 |
| Convenience | 9 | 5 |
| Affordability | 6 | 7 |
| Tolerance | 5 | 6 |
| Evidence | 10 | 10 |
Higher score = better on that axis. Editorial scoring; not a substitute for prescriber judgment.
Side effects compared
Both drugs share the GLP-1 class side-effect profile — primarily gastrointestinal (nausea, diarrhea, constipation, vomiting) in early treatment, fading as the body adapts. Both carry the FDA boxed warning for thyroid C-cell tumors and contraindications for personal/family history of medullary thyroid carcinoma.
Side-effect rate comparator
Trial-derived adverse-event rates with placebo delta. Sourced from FDA-approved labels for each drug. Most sources omit placebo rates entirely.
| Adverse event | Wegovy | Saxenda |
|---|---|---|
| Nausea | 44%(placebo 16%) +28.0 pp vs placebo | 39.3%(placebo 13.8%) +25.5 pp vs placebo |
| Diarrhea | 30%(placebo 16%) +14.0 pp vs placebo | 20.9%(placebo 9.9%) +11.0 pp vs placebo |
| Vomiting | 24%(placebo 6%) +18.0 pp vs placebo | 15.7%(placebo 3.9%) +11.8 pp vs placebo |
| Constipation | 24%(placebo 11%) +13.0 pp vs placebo | 19.4%(placebo 8.5%) +10.9 pp vs placebo |
| Abdominal pain | 20%(placebo 10%) +10.0 pp vs placebo | — |
| Headache | 14%(placebo 10%) +4.0 pp vs placebo | 13.6%(placebo 12.6%) +1.0 pp vs placebo |
| Injection-site reactions | — | 13.9%(placebo 10.5%) +3.4 pp vs placebo |
| Fatigue | 11%(placebo 5%) +6.0 pp vs placebo | 7.5%(placebo 4.6%) +2.9 pp vs placebo |
| Dyspepsia | — | 9.6%(placebo 2.7%) +6.9 pp vs placebo |
Patients who tolerate one GLP-1 well often (but not always) tolerate another. Switching between class members typically requires re-titration regardless of prior tolerability. See full side-effect breakdowns for Wegovy and Saxenda.
Dosing schedule comparison
Both medications use step-up titration to minimize side effects, but the schedule details differ:
Wegovy
- Weeks 1–4: 0.25 mg/week
- Weeks 5–8: 0.5 mg/week
- Weeks 9–12: 1 mg/week
- Weeks 13–16: 1.7 mg/week
- Week 17+: 2.4 mg/week
Saxenda
- Week 1: 0.6 mg/day
- Week 2: 1.2 mg/day
- Week 3: 1.8 mg/day
- Week 4: 2.4 mg/day
- Week 5+: 3 mg/day
See full titration guides for Wegovy dosing and Saxenda dosing.
Cost comparison
Cost differences between Wegovy and Saxenda depend on insurance coverage, manufacturer savings programs, and partner-network pricing — not just retail price.
- Average retail price (Wegovy): $1349/month
- Average retail price (Saxenda): $1349/month
- Wegovy savings card: as low as $25/month for eligible commercial-insured
- Saxenda savings card: no standing savings card
For most patients, the actual out-of-pocket cost is driven by: (1) what your insurance formulary tier places Wegovy vs Saxenda, (2) whether you qualify for manufacturer savings cards (commercial insurance only), and (3) telehealth partner network availability. Full cost breakdowns: Wegovy cost guide · Saxenda cost guide.
Which one to choose — decision factors
There's no single «better» drug — the right choice depends on individual circumstances. The key decision factors:
Choose Wegovy if…
- Your insurance covers it but not Saxenda
- Your prescriber has more experience with it
- Maximum weight loss is your priority (higher mean efficacy)
- You're commercially insured and want maximum savings-card benefit
Choose Saxenda if…
- Your insurance covers it but not Wegovy
- Your prescriber has more experience with it
Switching from Wegovy to Saxenda (or vice versa)
Switching between Wegovy and Saxenda (different active ingredients) typically requires restarting titration from the lowest doseof the new drug. Different molecules have different potencies — your tolerated dose of one doesn't map directly to the other. Plan for:
- Return of titration-period side effects (nausea, GI) for 2-4 weeks on restart
- Possibly temporary weight regain during the transition
- Fresh insurance prior-authorization (different drug = new PA)
- 2-4 weeks for the new drug to reach steady-state plasma levels
FAQ — Wegovy vs Saxenda
Are Wegovy and Saxenda the same drug?
No — they contain different active ingredients (semaglutide and liraglutide). They belong to similar drug classes (GLP-1 family) but work via slightly different molecular targets.
Which is more effective for weight loss, Wegovy or Saxenda?
In separate pivotal trials, Wegovy produced 6.9 percentage points more weight loss than Saxenda on average (Wegovy 14.9% in STEP-1; Saxenda 8% in SCALE). These were different trials in different populations, not a head-to-head comparison, and individual responses vary widely.
Can I take Wegovy and Saxenda together?
No. Combining two GLP-1 receptor agonists provides no added benefit and dramatically increases side-effect risk. Standard practice is to switch between them, not combine them.
Which has fewer side effects, Wegovy or Saxenda?
Both mostly cause stomach side effects. In their labels' placebo-controlled tables, nausea was reported by 44% on Wegovy (placebo 16%) and 39.3% on Saxenda (placebo 13.8%). The trials used different doses and populations, so this is not a head-to-head comparison.
Will my insurance cover Wegovy but not Saxenda?
Often the coverage differs. Insurance formularies are negotiated separately per drug — Wegovy may be on Tier 2 of your plan while Saxenda is Tier 4 or excluded. Check your formulary before assuming both are equally accessible.
Editorial comparison based on FDA prescribing information and published clinical data. Not a substitute for prescriber consultation. Full medical disclaimer.