How Much Weight People Lost on Zepbound, Wegovy and Foundayo
Average weight loss from the main trials for tirzepatide, semaglutide and orforglipron — the dose ramp for each, and when the weight actually comes off.
Three medications dominate the conversation. Here's what each did in its main trial.
| Medication | Brand | How it's taken | Average weight loss |
|---|---|---|---|
| Tirzepatide 15mg | Zepbound, Mounjaro | Weekly injection | -20.9% at 72 weeks (SURMOUNT-1) |
| Semaglutide 2.4mg | Wegovy, Ozempic | Weekly injection | -14.9% at 68 weeks (STEP 1) |
| Orforglipron 36mg | Foundayo | Daily tablet | -7.9% at 40 weeks (ACHIEVE-1) |
Important
These are three separate trials, not a head-to-head comparison. They enrolled different people, ran for different lengths of time, and measured different things.
SURMOUNT-1 and STEP 1 studied adults with obesity without diabetes, over 72 and 68 weeks. ACHIEVE-1 studied adults with type 2 diabetes, over 40 weeks — a shorter trial in a population that typically loses less weight on any of these medications.
Lining the numbers up in a table makes them look comparable. They are not. Reading this as a ranking is the single most common mistake made with these figures.
Semaglutide now goes higher
Wegovy HD (7.2mg) launched in the US in April 2026, stepping up after at least four weeks at 2.4mg. In STEP UP at 72 weeks it reached -20.7%, against -17.5% for 2.4mg.
The ramp, for each one
Nobody starts at the dose that produced the headline.
Semaglutide (Wegovy) — full dose at week 17
| Weeks | 1–4 | 5–8 | 9–12 | 13–16 | 17+ |
|---|---|---|---|---|---|
| Dose | 0.25mg | 0.5mg | 1.0mg | 1.7mg | 2.4mg |
Tirzepatide (Zepbound) — full dose at week 21
| Weeks | 1–4 | 5–8 | 9–12 | 13–16 | 17–20 | 21+ |
|---|---|---|---|---|---|---|
| Dose | 2.5mg | 5mg | 7.5mg | 10mg | 12.5mg | 15mg |
5mg and 10mg are maintenance doses in their own right — plenty of people stop climbing before 15mg.
Orforglipron (Foundayo) — a daily tablet. Starts at 1mg, steps up every four weeks to the assigned maintenance dose.
Key point
Four weeks per step, and four to five months before anyone is on the dose the headline came from. A result at week 8 is not a result on the medication as studied.
When does the weight actually come off?
The honest caveat first: trials publish curves and endpoints, not per-step deltas. Nobody reports "X% in weeks 5–8." But the checkpoints that exist are informative.
STEP 4 ran a 20-week lead-in on semaglutide using the standard escalation and weighed everyone before randomising. Mean loss: -10.6%. Against STEP 1's -14.9% at 68 weeks, that means the ramp does roughly two-thirds of the total work, and the remaining year adds the rest more slowly.
Tirzepatide matches: in SURMOUNT-1, 82% had lost 5% or more by week 12 — halfway up a 20-week ladder.
Expect the curve to steepen as the dose climbs, then flatten.
If you're behind that
Being slow early is weaker evidence than it feels.
- Semaglutide. 12% hadn't lost 5% at week 20 — past full dose. About 57% got there anyway, averaging -6.4%. The same slow starters switched to placebo finished at -0.3%.
- Tirzepatide. 18% were under 5% at week 12. 70% reached it by week 24, 90% by week 72.
Early response predicted success strongly. Early non-response predicted failure only weakly.
The number that matters more
These are averages, and the spread inside each trial is enormous — in STEP 1 the standard deviation was 9.3 percentage points. Plenty of people lost 25%, plenty lost 5%, and both sit inside the range that produced a -14.9% average.
Which means the gap between these three numbers is smaller than the gap between two people taking the same drug. Ranking them matters far less than finding the one that fits: what you can tolerate, what you can afford, what suits how you live, and what your prescriber recommends for your situation.
Use the figures as a sanity check, not a target. Being below an average that half the trial was also below is not, by itself, a sign anything is wrong.
Important
Educational information, not medical advice. This is not a recommendation of any medication, and nothing here should be used to choose or change a treatment.
Every trial above paired the medication with diet and activity counselling — the drug was not working alone. Dose schedules are what the trials used; yours is set by your clinician and may differ for good reasons.
Talk to your healthcare provider about which medication, if any, is appropriate for you, and before starting, stopping or changing any dose.
More: what the trials say if nothing is happening yet and what the research says about muscle loss.
This article is general education, not medical advice. Talk to your healthcare provider about your own treatment.