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Medications

Which GLP-1 is best for weight loss

In the only head-to-head trial so far, people on tirzepatide lost about 20% of their weight, compared with about 14% on semaglutide.

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The short answer

If you only look at average weight loss, tirzepatide (sold as Zepbound for weight) leads right now. Semaglutide (Wegovy, and the newer Wegovy pill) comes next, and liraglutide (Saxenda) is the older daily option.

But "best" is personal. The right medicine is the one you can get, afford, tolerate and keep taking. That's a conversation for you and a prescriber, and these numbers make it a better one.

Trial results side by side

MedicineHow you take itAverage lossPlaceboTrial
Zepbound 15 mg (tirzepatide)Weekly shot20.9%3.1%SURMOUNT-1, 72 weeks
Wegovy 2.4 mg (semaglutide)Weekly shot14.9%2.4%STEP 1, 68 weeks
Wegovy pill 25 mg (oral semaglutide)Daily tabletabout 13.6%2.2%OASIS 4, 64 weeks
Saxenda 3 mg (liraglutide)Daily shot8.0%2.6%SCALE, 56 weeks

These come from separate trials with different people and lengths, so they aren't a true ranking. The one direct comparison, SURMOUNT-5 (published 2025), found an average loss of about 20.2% on tirzepatide vs about 13.7% on semaglutide over 72 weeks.

Want to see what these averages could mean at your weight? Try the weight-loss projection.

Explainer · 0:23

1 · THE GUT HORMONE GLP-1 the medicine copies it and lasts for days 2 · SLOWER EMPTYING full sooner, full for longer 3 · THE BRAIN lowhigh HUNGER 4 · BLOOD SUGAR blood sugar after a meal + insulin withoutwith GLP-1 tirzepatide: + GIP 0:23 · voiced · captions on
After you eat, your gut releases a hormone called GLP-1. GLP-1 medicines copy it, but last much longer in the body.
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How GLP-1 medicines work
Read the transcript
  1. After you eat, your gut releases a hormone called GLP-1. GLP-1 medicines copy it, but last much longer in the body.
  2. It slows how fast your stomach empties, so you feel full sooner and stay full for longer.
  3. It also acts on appetite centers in the brain, which quiets hunger and constant thoughts about food.
  4. When blood sugar is high, it helps the pancreas release insulin. Tirzepatide also acts on a second gut hormone, GIP.

What else matters besides the number

  • What it's approved for. Wegovy is also approved to lower the risk of heart attack and stroke in people with heart disease. Zepbound is also approved for moderate to severe sleep apnea with obesity.
  • Side effects. Stomach effects are common on all of them. On the labels, nausea showed up in 44% of people on Wegovy (16% on placebo) and 25% to 29% on Zepbound (9% on placebo). See nausea on GLP-1s.
  • Your routine. A weekly shot, a daily shot, or a daily pill you take on an empty stomach. The best routine is the one you'll stick with.
  • Coverage and cost. Many plans cover one brand and not another. Compare options in the GLP-1 cost index.

Ozempic and Mounjaro are the diabetes versions

Ozempic contains the same medicine as Wegovy, and Mounjaro the same as Zepbound. They're approved for type 2 diabetes, at different doses. If weight management is the goal, the weight-approved brands are the ones designed and dosed for it. Side by side: Ozempic vs Wegovy and Mounjaro vs Zepbound.

How to find your best fit

  1. Check where your BMI sits against the label thresholds with the BMI calculator.
  2. List any conditions you have, like heart disease, sleep apnea or type 2 diabetes. They change which brand fits.
  3. Ask your plan which GLP-1s it covers, or compare self-pay options.
  4. Talk it through with a licensed clinician. If you don't have one, we can help you find a clinician in your state.

How many people reach common goals

Averages hide a wide spread. Some people lose far more than the average and some lose less. The main trials also reported how many people reached common milestones:

Medicine and trialLost at least 5%Lost at least 10%Lost at least 20%
Zepbound 15 mg, SURMOUNT-1about 9 in 10about 8 in 10more than half
Wegovy 2.4 mg, STEP 186%69%about a third
Saxenda 3 mg, SCALEabout 63%about 33%not a main result

For someone at 220 lb, 5% is 11 lb, 10% is 22 lb and 20% is 44 lb. Even the first 5% can help blood pressure and blood sugar: see how weight loss lowers blood pressure.

Common mistakes when comparing GLP-1s

  • Treating separate trials as one race. The people, trial lengths and dose rules all differed, so small gaps between them may not be real.
  • Judging a medicine in the first month. Every label starts with a low dose so your stomach can adjust. The early weeks don't show the full effect. See how the steps work with the dose schedule.
  • Forgetting about muscle. Some of the weight lost on any GLP-1 can be muscle. Protein and strength training help: read muscle loss on GLP-1s.
  • Skipping the long view. Studies show weight often comes back after stopping. A medicine you can stay on, with side effects you can live with, may serve you better than the one with the biggest headline.

When to talk to your doctor

  • Before starting, switching or stopping any GLP-1.
  • If you or a family member has had medullary thyroid cancer or MEN 2.
  • If you have severe stomach pain that won't go away, or can't keep fluids down.
  • If you're pregnant, planning pregnancy or have had pancreatitis.

Run your numbers

GLP-1 weight-loss projection

Expected loss by drug, dose and week, from trial data

Open

BMI and GLP-1 eligibility

Your BMI and where it sits against label thresholds

Open

GLP-1 cost and savings

List, self-pay and savings-card prices side by side

Open

Keep reading

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Common questions

Which GLP-1 causes the most weight loss?

In trials so far, tirzepatide (Zepbound) has produced the largest average loss, about 20% at the highest dose. Results vary a lot from person to person.

Is Zepbound better than Wegovy?

In the SURMOUNT-5 head-to-head trial, average loss was about 20.2% on tirzepatide vs about 13.7% on semaglutide. Better also depends on side effects, coverage and your health history.

Is there a GLP-1 pill for weight loss?

Yes. The Wegovy pill (oral semaglutide 25 mg) is approved for weight management and averaged about 13.6% loss in its main trial.

Can I choose which GLP-1 I get?

You can share your preference, but a licensed prescriber decides what's appropriate, and your insurance may favor one brand.

Sources

  1. Jastreboff et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). NEJM 2022
  2. Wilding et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). NEJM 2021
  3. Pi-Sunyer et al. A randomized, controlled trial of 3.0 mg of liraglutide in weight management (SCALE). NEJM 2015
  4. SURMOUNT-5: tirzepatide vs semaglutide head-to-head trial (NEJM, 2025)
  5. Wegovy and Wegovy pill prescribing information (FDA label on DailyMed)
  6. Zepbound prescribing information (FDA label on DailyMed)

Clinician review pending. Drafted from primary sources and waiting for sign-off by a licensed clinician (MD, DO or PharmD) before launch. Every number is checked against its source. Drug facts are re-checked quarterly, prices monthly and whenever a label changes. How we review · Report an error