The first 16 to 20 weeks are the ramp
Both drugs are started low and raised in steps, because that is what keeps nausea manageable. Wegovy's schedule reaches the 2.4 mg maintenance dose at week 17; Zepbound reaches 15 mg, if that is the target, at about week 20.[1][2] So for the first four to five months most people are on a lower dose than the trial headline numbers were measured at.
- Days to weeks: appetite In the semaglutide feeding study, hunger and cravings were already lower by the time the full dose was reached; by week 20, people ate about a third less at a test lunch.[3]
- Week 20: about 10% down on semaglutide In STEP 4, 803 adults lost a mean 10.6% of body weight during the 20-week run-in on semaglutide 2.4 mg.[4]
- Week 36: about 21% down on tirzepatide In SURMOUNT-4, 783 adults lost a mean 20.9% during 36 weeks of open-label tirzepatide at 10 or 15 mg.[5]
- Month 12 to 17: levelling off In STEP 1 the weight curve flattened in the final months of the 68-week trial; in the Zepbound trials the plateau came later and lower.[6][2]
By month five
The 10.6% figure at week 20 is the most useful single number for a new user, because it was measured in a large group during the exact ramp most people follow.[4] It is a mean: some people lost much more and some lost little. Trials measured the group; nobody can tell an individual where they will fall.
By one year and beyond
In the Wegovy trial, 83.5% of people on the drug lost at least 5% of their body weight and 66.1% lost at least 10%, against 31.1% and 12.0% on placebo.[1] In the Zepbound trial, 85 to 91% lost at least 5% and 69 to 80% lost at least 10%, depending on dose, against 35% and 19% on placebo.[2]
The spread between people
Turn those percentages around: about 1 in 6 people on Wegovy and about 1 in 10 on Zepbound did not reach 5% loss by the end of the trial.[1][2] Trials call them non-responders. There is no reliable test in advance for who will respond, and the labels do not define a point at which a prescriber should decide. That conversation is in why the scale stops moving.
Heard vs evidence
The short version
Short on the way. A 35-second captioned version of this page is in production for the Fewer Bites channel. It will be embedded here when it is live.
Questions to bring to your prescriber
Print these or screenshot them. They are conversation starters, not a checklist of things to do.
- What dose am I on now, and where in the escalation schedule am I?
- At what point would you want to look at how I am responding, and what would you look at besides the scale?
- What side effects would make you slow the ramp for me rather than push on?
Education, not advice. This page explains what trials, labels and guidelines report. It does not tell anyone to start, change or stop a medicine. Your prescriber knows your history; this page does not.
Sources
- Novo Nordisk / FDA. Wegovy (semaglutide) injection and tablets, prescribing information, revised 06/2026. label
- Eli Lilly / FDA. Zepbound (tirzepatide) prescribing information, revised 08/2026. label
- Friedrichsen M et al. Effect of semaglutide 2.4 mg on gastric emptying, appetite and energy intake in adults with obesity. Diabetes Obes Metab 2021;23:754–62. primary read · RCT · industry-funded
- 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
- Aronne LJ et al. Continued treatment with tirzepatide for maintenance of weight reduction (SURMOUNT-4). JAMA 2024;331:38–48. primary read · RCT · industry-funded
- 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