Not losing weight, or it stopped

Losing little from the start

In the Wegovy trial, 83.5% lost at least 5% of their body weight, which means 16.5% did not.^[1] In the Zepbound trial, 85 to 91% reached 5%, so 9 to 15% did not.^[2] There is no test that predicts in advance who will respond. Before calling it non-response, remember that the first four to five months are spent working up to the full dose, and the headline numbers were measured at the full dose much later (see how long it takes).^[1][2]

Losing, then levelling off

In STEP 1, weight loss slowed and levelled off in the last months of the 68-week trial.^[3] In the Zepbound trial the curve flattened later and lower, around 72 weeks.^[2] A plateau after months of loss is the expected shape of the curve, not a sign the drug stopped working: in a 60-week trial, people on semaglutide were still eating 24% less than the placebo group at week 60.^[4]

Why the curve flattens

A smaller body needs less energy, so eating less brings weight down until intake and needs match again at a lower weight. The drug keeps intake lower, but at some point the new lower intake is simply what the new lower weight requires.^[4][5] That explains why the curve flattens instead of continuing down forever. It is a reasoned explanation consistent with the trial data, not something these trials measured directly.

What the trials tested

The trials tested what happens if you keep going or stop. In STEP 4, people who continued semaglutide after week 20 lost a further 7.9%, while those switched to placebo regained 6.9%.^[6] Higher doses lost more on average in the Zepbound trial (15.0%, 19.5% and 20.9% at 5, 10 and 15 mg).^[2] Whether a dose change, a different medicine or a different plan makes sense for one person is a prescriber decision; this page does not suggest one.

Heard vs evidence

The short version

Questions to bring to your prescriber

Print these or screenshot them. They are conversation starters, not a checklist of things to do.

• Am I at the full dose yet, and how long have I been on it?
• Besides the scale, what would you look at to judge whether this medicine is helping me (waist, blood pressure, blood sugar, how I feel)?
• If I have plateaued, what are the options you would consider, and what are the trade-offs of each?

Sources

Every number on this page traces to one of these. "Primary read" means the full paper or label was read; "abstract only" means only the abstract was available; "secondary" means the figure was taken from a named review.

1. Novo Nordisk / FDA. Wegovy (semaglutide) injection and tablets, prescribing information, revised 06/2026. label
2. Eli Lilly / FDA. Zepbound (tirzepatide) prescribing information, revised 08/2026. label
3. Wilding JPH et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med 2021;384:989–1002. primary read · RCT · industry-funded
4. Randomized 60-week trial of semaglutide 2.4 mg on energy intake and appetite (NCT05548647). secondary · figures via Fewer Bites eating dossier
5. Christensen S et al. Dietary intake by patients taking GLP-1 and dual GIP/GLP-1 receptor agonists: a narrative review. Obesity Pillars 2024. secondary · review
6. Rubino D et al. Effect of continued weekly subcutaneous semaglutide vs placebo on weight loss maintenance (STEP 4). JAMA 2021;325:1414–25. primary read · RCT · industry-funded

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