How Much Weight Do People Lose on Ozempic, Wegovy or Zepbound? Trial Data

In the STEP 1 trial, semaglutide 2.4 mg once a week, the usual maintenance dose of Wegovy, lowered body weight by an average of 14.9% over 68 weeks in 1,961 adults with obesity or overweight and no diabetes, versus 2.4% on placebo: 12.4 points more. The US Wegovy label also includes a higher 7.2 mg weekly dose for weight reduction in adults; in the STEP UP trial, the label reports weight changes of −18.8% with 7.2 mg, −15.5% with 2.4 mg and −3.9% with placebo at 72 weeks. Tirzepatide, sold as Zepbound for weight management, lowered weight by 15.0%, 19.5% and 20.9% on 5, 10 and 15 mg over 72 weeks in SURMOUNT-1, with 2,539 adults without diabetes, versus 3.1% on placebo: 11.9 to 17.8 points more.

Ozempic is semaglutide at lower doses, approved for type 2 diabetes, and Mounjaro is tirzepatide for the same condition. In a 30-week Ozempic trial in adults with type 2 diabetes, the US Ozempic label reports mean weight changes of −3.8 kg with 0.5 mg and −4.7 kg with 1 mg, versus −1.2 kg with placebo: about 8.4, 10.4 and 2.6 lb.

These are trial averages, from selected people who also got diet and activity counseling. Here I explain how to read them, how many people reach each threshold, what the curve looks like and why results vary from person to person. This isn’t a treatment guide: your dose and your goals are something to work out with your prescriber. What these medications are and how they work is in what GLP-1 medications are, and each active ingredient has a reference page in our drug section (in Spanish).

How to read these numbers

It’s an average, not a promise. In every group, some people lost much more and others lost little. In STEP 1, according to the US Wegovy label, 83.5% of people on semaglutide lost at least 5% of their body weight. Put the other way, roughly one in six didn’t reach 5%.

Compared with placebo. In these trials, the placebo group got the same diet and activity counseling and also lost some weight, between 2% and 3.5%. The gap between the two groups, in percentage points, is what’s attributed to the drug.

Who took part. STEP 1 and SURMOUNT-1 excluded people with diabetes, and most participants were women. The SELECT trial shows how much the result shifts with a different population. It enrolled 17,604 adults aged 45 or older with cardiovascular disease and no diabetes. At 208 weeks, weight was down 10.2% on semaglutide 2.4 mg and 1.5% on placebo (difference −8.7 points; 95% CI −9.42 to −7.88). The 95% CI, or confidence interval, is the range where the true effect probably lies. The authors explain the gap this way: SELECT had more men (only 27.7% women, versus 73.1% in STEP 1), a lower average BMI (body mass index), and weight loss wasn’t the goal. Investigators could also lower the dose or pause treatment.

Who stayed on treatment. The headline numbers count everyone who was randomized, including people who stopped. In STEP 1, the EU prescribing information for Wegovy notes that 17.1% of people on semaglutide stopped it for good; assuming everyone had stayed on treatment, the estimated loss rises to 16.9%. That’s why you’ll see different numbers for the same trial. The EU prescribing information for Mounjaro gives 16.0%, 21.4% and 22.5% for SURMOUNT-1, using that kind of analysis. The US labels report the figures that count everyone.

Outside the trials. A 2022 retrospective study reviewed patients at a specialized obesity clinic treated with semaglutide 1.7 or 2.4 mg. They lost an average of 5.9% at 3 months (175 people) and 10.9% at 6 months (102 people), similar to the trials. But of 408 people with a prescription, only those were analyzed, and follow-up stopped at 6 months.

Results by drug and trial

Average weight change at the end of each trial. All figures include people who stopped treatment.

Trial and population	Group (n)	Length	Average weight change	Difference vs. placebo (95% CI)
STEP 1: obesity or overweight, no diabetes	Semaglutide 2.4 mg (1,306)	68 weeks	−14.9% (placebo, 655: −2.4%)	−12.4 (−13.4 to −11.5)
STEP 2: with type 2 diabetes	Semaglutide 2.4 mg (404)	68 weeks	−9.6% (placebo, 403: −3.4%)	−6.2 (−7.3 to −5.2)
STEP UP: obesity, no diabetes	Semaglutide 7.2 mg (1,005)	72 weeks	−18.7% (2.4 mg, 201: −15.6%; placebo, 201: −3.9%)	−14.8 (−16.2 to −13.4)
Wegovy tablet trial (Study 7 in the US label): obesity or overweight, no diabetes	Oral semaglutide 25 mg daily (205)	64 weeks	−13.6% (placebo, 102: −2.4%)	−11.2 (−13.6 to −8.8)
SURMOUNT-1: obesity or overweight, no diabetes	Tirzepatide 5 mg (630)	72 weeks	−15.0% (placebo, 643: −3.1%)	−11.9 (−13.4 to −10.4)
	Tirzepatide 10 mg (636)	72 weeks	−19.5%	−16.4 (−17.9 to −14.8)
	Tirzepatide 15 mg (630)	72 weeks	−20.9%	−17.8 (−19.3 to −16.3)
SURMOUNT-2: with type 2 diabetes	Tirzepatide 10 mg (312)	72 weeks	−12.8% (placebo, 315: −3.2%)	−9.6 (−11.1 to −8.1)
	Tirzepatide 15 mg (311)	72 weeks	−14.7%	−11.6 (−13.0 to −10.1)

For STEP UP, the table shows the published paper; the US label, which handles missing data slightly differently, gives 18.8%, 15.5% and 3.9%.

And how many people reached each weight-loss threshold. Placebo in parentheses:

Group	≥ 5%	≥ 10%	≥ 15%	≥ 20%
STEP 1, semaglutide 2.4 mg	83.5% (31.1%)	66.1% (12.0%)	47.9% (4.8%)	30.2% (1.7%)
STEP 2, semaglutide 2.4 mg	67.4% (30.2%)	44.5% (10.2%)	25.1% (4.3%)	12.8% (2.3%)
STEP UP, semaglutide 7.2 mg	88.7% (38.3%)	79.8% (20.3%)	63.8% (7.5%)	45.5% (2.8%)
Wegovy tablet trial, 25 mg	76.3% (31.3%)	59.8% (14.4%)	47.0% (5.5%)	27.9% (3.1%)
SURMOUNT-1, tirzepatide 5 mg	85.1% (34.5%)	68.5% (18.8%)	48.0% (8.8%)	30.0% (3.1%)
SURMOUNT-1, tirzepatide 10 mg	88.9%	78.1%	66.6%	50.1%
SURMOUNT-1, tirzepatide 15 mg	90.9%	83.5%	70.6%	56.7%
SURMOUNT-2, tirzepatide 10 mg	79.2% (32.5%)	60.5% (9.5%)	39.7% (2.7%)	21.5% (1.0%)
SURMOUNT-2, tirzepatide 15 mg	82.8%	64.8%	48.0%	30.8%

Sources for the second table: US labels for Wegovy (Studies 2, 3, 7 and 8, which are STEP 1, STEP 2, the tablet trial and STEP UP) and Zepbound (Studies 1 and 2, which are SURMOUNT-1 and SURMOUNT-2). The published STEP 1 and STEP 2 papers give slightly different percentages, because they calculate them only for people with data at the end.

The trials can’t be compared with each other: they have different populations, lengths and methods. The only published head-to-head comparison in obesity is SURMOUNT-5, which I summarize in the FAQ.

The typical curve: when most of the weight comes off

Weight comes off fastest at the start and then slows. The trials that gave everyone the drug for an initial period show it clearly:

• Semaglutide. In STEP 4, the 803 people who reached 2.4 mg lost 10.6% in the first 20 weeks. Those who stayed on the drug lost another 7.9%, measured from week 20, over the next 48 weeks.
• Tirzepatide. In SURMOUNT-4, the 670 participants who made it to randomization (the draw between continuing or switching to placebo) had lost 20.9% in 36 weeks. Those who continued lost another 5.5%, measured from week 36, over the next 52 weeks.

When does it level off completely? For semaglutide, the EU prescribing information for Wegovy says that in STEP 1 weight loss occurred early and continued throughout the trial. In STEP 5, a 2-year trial with 304 people, mean body weight decreased through week 68 and then reached a plateau, with a final change of −15.2%. The US label shows the same kind of curves as figures but doesn’t describe them in words. In SELECT, weight loss continued until week 65 and held through week 208.

For tirzepatide, an analysis of SURMOUNT-1 measured when each person reached their own plateau. It defined a plateau as losing less than 5% over a 12-week period and every period after it. It included 1,438 participants who stayed on treatment and lost at least 5%. The median (the middle value) was 24 to 36 weeks, depending on starting BMI, and by week 72 between 87.6% and 90.2% were on a plateau. In the group with prediabetes followed for 3 years, weight loss at 176 weeks was 12.3%, 18.7% and 19.7% on 5, 10 and 15 mg, versus 1.3% on placebo.

In short: with semaglutide, the group average stopped dropping around weeks 65 to 68. With tirzepatide, using that analysis’s definition, half of people leveled off before weeks 24 to 36, although in SURMOUNT-4 those who continued still lost some weight between weeks 36 and 88.

Why results differ from person to person

• Type 2 diabetes. People with diabetes lose less: versus placebo, 6.2 points in STEP 2 against 12.4 in STEP 1, and 11.6 against 17.8 on tirzepatide 15 mg in SURMOUNT-2 and SURMOUNT-1. In the retrospective semaglutide study, 6-month loss was 7.2% with diabetes and 11.8% without.
• Sex and starting weight. Both US labels say weight went down across subgroups, including by age, sex and starting BMI. The EU prescribing information for Wegovy goes further: relatively greater weight loss was observed in women, in people without type 2 diabetes and in those with a lower starting body weight. In SELECT, at 104 weeks, the difference versus placebo was −11.1 points in women and −7.5 in men; there, by contrast, a lower BMI was linked to losing less.
• Age. In SELECT, younger people lost a little more, but the gap between age groups was small. The STEP 1 extension found no differences by age.
• Response. Trials usually define “response” as losing at least 5%. In the SURMOUNT-1 analysis of people who took at least 75% of their doses, only 28 of 1,545 (1.8%) hadn’t reached 5% by week 72.

What the first few months predict

There isn’t much data, and nearly all of it comes from post hoc analyses: done afterward, with data already collected, and funded by the manufacturers. Here’s what they show:

• Tirzepatide, week 12. In Ard and colleagues’ analysis of 1,545 SURMOUNT-1 participants who took at least 75% of their doses, 82% had already lost 5% by week 12. That group reached an average of 22.5% at week 72. The other 18% reached 11.0%, and 90% of them got to 5%, after about 25 weeks on average.
• Tirzepatide, week 8. In an analysis of SURMOUNT-1 and SURMOUNT-2, 62.1% of participants without diabetes and 40.6% of those with diabetes had lost 5% by week 8. At 72 weeks, early responders lost 23.3% versus 14.6% for everyone else (without diabetes), and 20.0% versus 10.8% (with diabetes).
• Semaglutide, week 20. In a STEP 4 conference abstract, 88.0% of people who stayed on semaglutide had lost 5% by week 20, and they reached 19.7% at week 68. The rest reached 6.4% if they continued and 0.3% if they switched to placebo.

Losing early is linked to losing more in the end, but losing little at first doesn’t mean the drug won’t work. Ard and colleagues think 12 weeks may be too soon to judge tirzepatide, because dose escalation lasts up to 20 weeks. How to read your own progress is a conversation for you and your prescriber.

The plateau

Reaching a point where your weight stops dropping is expected, not a failure: in SURMOUNT-1, nearly 9 in 10 of the people analyzed were on a plateau by around week 72. In that analysis, the plateau came 4.2 weeks later in women than in men, and somewhat later on higher doses and in younger people.

If the numbers on the scale start to take over your day, or you find yourself eating less than you need to push past a plateau, talk to your doctor or a registered dietitian. MedlinePlus points out that eating disorders are serious and treatable.

What happens when treatment stops

When people stop semaglutide or tirzepatide, they regain a good part of the weight they lost, on average: in the STEP 1 extension, about two-thirds within a year. I cover it in detail in what happens when you stop Ozempic, Wegovy or Zepbound.

Drugs in development

These data come from published trials. Of these drugs, only orforglipron is approved in the US so far.

Drug	Status	Trial and population	Result
Retatrutide (weekly)	In development (phase 3), not approved anywhere	Phase 2: 338 adults with obesity or overweight, no diabetes	−24.2% on 12 mg at 48 weeks, versus −2.1% on placebo; −17.5% versus −1.6% at 24 weeks
		TRANSCEND-T2D-1 (phase 3): 537 adults with type 2 diabetes	−15.3% on 12 mg at 40 weeks, versus −2.6% on placebo
CagriSema (cagrilintide plus semaglutide, weekly)	In development, not approved anywhere; Novo Nordisk submitted it to the FDA in December 2025	REDEFINE 1: 3,417 adults with obesity or overweight, no diabetes	−20.4% versus −3.0% at 68 weeks (difference −17.3; 95% CI −18.1 to −16.6)
		REDEFINE 2: 1,206 adults with type 2 diabetes	−13.7% versus −3.4% at 68 weeks
Orforglipron (oral, daily)	FDA-approved as Foundayo on April 1, 2026, for weight management; also authorized in the UK and under review by the EMA	ATTAIN-1: 3,127 adults with obesity or overweight, no diabetes	−11.2% on 36 mg at 72 weeks, versus −2.1% (difference −9.1; 95% CI −10.1 to −8.1)
		ACHIEVE-1: 559 adults with recent-onset type 2 diabetes	−7.6% on 36 mg at 40 weeks, versus −1.7%

A note on Foundayo’s doses: the US label presents ATTAIN-1 with the trial doses converted to the marketed tablet strengths, so the numbers don’t match the paper. At the highest strength, 17.2 mg, it reports −11.1% versus −2.1% on placebo at 72 weeks.

In REDEFINE 1, dose adjustments were allowed, which makes the results harder to read. And the pattern repeats: with type 2 diabetes, weight loss is smaller.

Frequently asked questions

How much weight do you lose in the first month?

The main papers don’t give a written first-month average. The trials start at the lowest dose and raise it gradually. The earliest figure I’ve found is from week 8 with tirzepatide: 62.1% of participants without diabetes had already lost 5%. In the retrospective semaglutide study, the average at 3 months was 5.9%.

How much weight do people lose on Ozempic, as opposed to Wegovy?

According to its US label, Ozempic is indicated for adults with type 2 diabetes, to improve blood sugar control and lower cardiovascular and kidney risk; it isn’t approved for weight management. In the 30-week trial above, people lost 3.8 kg (8.4 lb) on 0.5 mg and 4.7 kg (10.4 lb) on 1 mg. In a 40-week trial, the label reports −6.4 kg with 2 mg and −5.6 kg with 1 mg, about 14.1 and 12.3 lb. The EU prescribing information for Ozempic adds the 2-year SUSTAIN 6 trial, in people with type 2 diabetes and high cardiovascular risk: −3.6 kg and −4.9 kg on 0.5 mg and 1 mg, versus −0.7 kg and −0.5 kg on placebo. These are absolute amounts, not percentages, in a different population, so they can’t be compared directly with STEP 1.

How many pounds is 15%?

It depends on where you start. In STEP 1, with an average starting weight of 105 kg (about 231 lb), average loss was 15.3 kg (33.7 lb) on semaglutide and 2.6 kg (5.7 lb) on placebo over 68 weeks.

Do diet and exercise make a difference?

All participants got diet and activity counseling. In STEP 3, which added intensive behavioral therapy and an initial 8-week low-calorie diet, the US Wegovy label reports weight changes of −16.0% on semaglutide and −5.7% on placebo at 68 weeks. To protect your muscle, read protein and muscle on GLP-1 medications and estimate your number with the protein calculator (in Spanish, in kilograms). For planning meals, see what to eat on GLP-1 medications.

Do people lose more on Zepbound than on Wegovy?

In SURMOUNT-5, 751 adults with obesity and no diabetes lost 20.2% on tirzepatide and 13.7% on semaglutide over 72 weeks (difference −6.5 points; 95% CI −8.1 to −4.9). It was funded by Eli Lilly, which makes tirzepatide, and participants knew which drug they were getting. Which treatment fits a given person depends on many factors and is decided with a doctor.

Why do some people lose less than average?

The trials point to several factors: having type 2 diabetes, being male, being on lower doses, or stopping treatment. On top of that, the US Wegovy label says that if a dose isn’t tolerated during escalation, delaying the next increase for 4 weeks may be considered; that’s your prescriber’s decision, and it also shapes the result. If your progress worries you, bring it up with your doctor.