How Much Weight Can You Lose on Semaglutide or Tirzepatide?
What the large clinical trials showed about weight loss on semaglutide and tirzepatide, how fast it usually happens, and what makes the biggest difference for real people.
Published 2026-11-13 by Avere Beauty
It's the first question almost everyone asks at their consultation, and it's a fair one. The honest answer: it depends on you. But the large clinical trials give a good picture of what's typical.
Written by the Avere Beauty weight loss team · November 2026
What the clinical trials showed
Semaglutide. In the STEP 1 trial, adults with obesity or overweight who took semaglutide 2.4 mg once a week lost about 15% of their body weight on average over 68 weeks. People on placebo lost about 2%. Both groups also had lifestyle counseling.
Tirzepatide. In the SURMOUNT-1 trial, adults took tirzepatide at 5, 10 or 15 mg weekly for 72 weeks. Average weight loss was about 15%, 19.5% and 21% depending on the dose, compared with about 3% on placebo.
To put that in real numbers: for someone who weighs 220 pounds, 15% is about 33 pounds and 20% is about 44 pounds.
Averages aren't promises
An average means some people lost much more and some lost less. In these trials, a meaningful share of people lost 20% or more, while a smaller group lost under 5%. Results depend on your starting point, your dose, how well you tolerate the medication, your sleep, your activity, other medications you take and health conditions like thyroid problems or PCOS.
What the timeline usually looks like
- The first month or two: you start at a low dose so your body can adjust. Appetite often drops quickly, but the scale may move slowly at first.
- Months three to nine: as you reach your working dose, this is usually when the steadiest loss happens.
- After about a year: progress tends to slow and level off. That's expected, and it's when the focus shifts to keeping your results.
What makes the biggest difference
- Protein at every meal, so you lose fat and keep muscle. See how to protect your muscle and your face.
- Strength training two to three times a week, even with light weights or bands.
- Staying consistent with your weekly dose and check-ins.
- Managing side effects early, so you can stay on track. Here's how to ease nausea and constipation.
- A plan for later. People who stop treatment often regain weight. Read what happens when you stop a GLP-1.
Semaglutide or tirzepatide?
On average, tirzepatide led to more weight loss in trials, but averages aren't the whole story. Some people do better on one than the other, and some prefer a pill like Contrave. Our comparison of semaglutide vs. tirzepatide walks through the differences, and your nurse practitioner will help you choose.
Frequently asked questions
How much weight do people lose on semaglutide?
In the STEP 1 clinical trial, adults taking semaglutide 2.4 mg weekly lost about 15% of their body weight on average over 68 weeks, compared with about 2% on placebo. Individual results vary widely.
How much weight do people lose on tirzepatide?
In the SURMOUNT-1 clinical trial, adults taking tirzepatide lost about 15% to 21% of their body weight on average over 72 weeks, depending on the dose, compared with about 3% on placebo.
How fast will I lose weight on a GLP-1?
Weight loss is usually gradual. Doses start low and increase over several months, so most of the loss happens as you reach your working dose. Progress often slows after the first year and then levels off.
Is tirzepatide better than semaglutide?
On average, people lost more weight on tirzepatide in clinical trials, but the best choice depends on your health history, how you tolerate the medication and your goals. Your provider will help you decide.
Sources: Wilding JPH et al., "Once-Weekly Semaglutide in Adults with Overweight or Obesity" (STEP 1), New England Journal of Medicine, 2021. Jastreboff AM et al., "Tirzepatide Once Weekly for the Treatment of Obesity" (SURMOUNT-1), New England Journal of Medicine, 2022.
This article is general education, not medical advice. Weight loss medication is prescribed only after a provider reviews your health history, and results vary from person to person.
Ready to talk it through? Book a $50 weight loss consultation, call 412-952-7592, or read how our program works.
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