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Research goal

Semaglutide and weight loss

In STEP 1, a 68-week trial of 1,961 adults, weekly semaglutide 2.4 mg lowered body weight by 14.9% on average, against 2.4% on placebo, with lifestyle intervention in both groups.1 Wegovy is the semaglutide product FDA approved for weight management, and about two-thirds of the lost weight returned within a year of stopping in follow-up.23

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What sources report

How semaglutide lowers weight

The Wegovy label attributes the weight effect to lower calorie intake, likely through effects on appetite, and states that weight comes off with more fat mass than lean mass lost.10 GLP-1 receptors are present in brain areas involved in appetite.10

STEP 1: the main trial of semaglutide for weight loss

STEP 1 enrolled 1,961 adults without diabetes who had a BMI of 30 or more, or 27 or more with a weight-related condition.111 They took semaglutide 2.4 mg once weekly or placebo, with lifestyle intervention, for 68 weeks.1 Average weight change was -14.9% (-15.3 kg) vs -2.4% (-2.6 kg).1

Weight lost by week 68 Semaglutide1 Placebo
At least 5% 86.4% 31.5%
At least 10% 69.1% 12.0%
At least 15% 50.5% 4.9%

The spread was wide: about 1 in 7 people on semaglutide lost less than 5% of body weight, while half lost 15% or more.1

Higher dose, tablets and teenagers

In two 72-week studies on the Wegovy label, adults with obesity averaged -18.8% on 7.2 mg weekly, -15.5% on 2.4 mg and -3.9% on placebo.12 Adults with obesity and type 2 diabetes averaged -13.2%, -10.4% and -3.8% on the same three options.12 The 7.2 mg dose also brought more side effects, listed on Semaglutide side effects.13

Once-daily Wegovy 25 mg tablets produced an average weight change of -13.6% vs -2.4% on placebo at week 64.12 In patients aged 12 and older with obesity, BMI changed -16.1% on Wegovy 2.4 mg vs +0.6% on placebo at week 68.12

Compared with other drugs

STEP 8 compared weekly semaglutide 2.4 mg with daily liraglutide 3.0 mg in 338 adults without diabetes; at 68 weeks, weight changed -15.8% vs -6.4%.9 SURMOUNT-5 compared the maximum tolerated doses of semaglutide and tirzepatide in 751 adults with obesity and without type 2 diabetes for 72 weeks; tirzepatide produced -20.2% vs -13.7%.4 More on the second drug: Tirzepatide and weight loss and Mounjaro vs Semaglutide.

Keeping the weight off

STEP 4 tested what happens with and without continued treatment. 902 adults began a 20-week run-in on semaglutide; the 803 who reached 2.4 mg weekly, having lost 10.6% on average, were then randomized to continue semaglutide or switch to placebo.6 From week 20 to week 68, those who stayed on semaglutide lost a further 7.9%, while those switched to placebo regained 6.9%.6

The STEP 1 extension followed 327 people for a year after treatment stopped. Those who had taken semaglutide regained two-thirds of their prior weight loss, ending 5.6% below their starting weight at week 120, vs 0.1% for the placebo group.3 Most heart and metabolic improvements moved back toward baseline.3

Weight and heart risk

In SELECT, adults with heart disease and overweight or obesity but no diabetes had fewer major cardiovascular events on semaglutide (6.5% vs 8.0%).14 That trial is the basis for the heart-risk indication FDA added to Wegovy in March 2024.15 The full results are on Semaglutide benefits and uses.

What the label says

Wegovy is the semaglutide product approved for weight management. Its label covers reducing excess body weight and keeping it off long term, with a reduced-calorie diet and more physical activity.2 That use covers three groups: adults with obesity, adults with overweight and at least one weight-related condition, and children 12 and older with obesity.2 Wegovy tablets share the weight and heart indications but not the pediatric or MASH uses.162 Ozempic and Rybelsus carry type 2 diabetes indications only.78

A prescriber sets the dose. The injection starts at 0.25 mg once weekly and steps up every 4 weeks to a maintenance dose of 2.4 mg (or 1.7 mg) from week 17.5 For adults, the dose may go to a maximum of 7.2 mg once 2.4 mg has been tolerated for at least 4 weeks and more weight reduction is clinically indicated.5 Full schedules are on Semaglutide dosage.

The label does not recommend combining Wegovy with other semaglutide products or other GLP-1 receptor agonists.2 It carries a boxed warning for thyroid C-cell tumors seen in rodents, and its most common side effects are digestive, led by nausea in 44% vs 16% on placebo.1718

None of this applies to research-labeled semaglutide: the trials and label above concern semaglutide medicines, and FDA treats research-labeled products intended for people as unapproved new drugs.1920

More on this goal: Peptides and weight loss, Wegovy and weight loss, GLP-1 and weight loss and the full profile, What is Semaglutide?.

Read next

More goal pages

Frequently asked questions

Is semaglutide better than tirzepatide?

For weight, the head-to-head SURMOUNT-5 trial favored tirzepatide. It followed 751 adults with obesity and without type 2 diabetes for 72 weeks.4 At each drug's maximum tolerated dose, average weight change was -20.2% with tirzepatide vs -13.7% with semaglutide.4 Waist size fell 18.4 cm vs 13.0 cm, and gastrointestinal effects were the most common side effects with both drugs.4

How long does it take to lose 20 lbs on semaglutide?

No timeline can be promised, and results vary. In STEP 1, adults on semaglutide 2.4 mg weekly plus lifestyle intervention lost an average of 15.3 kg (about 34 lb) over 68 weeks, vs 2.6 kg on placebo.1 About 1 in 7 lost less than 5% of their weight.1 The Wegovy label builds the dose up over 16 weeks before the maintenance dose starts.5

Can I lose 20 pounds in a month with semaglutide?

The trial data do not support expecting that. The Wegovy maintenance dose is reached only after 16 weeks of gradual increases, starting at 0.25 mg once weekly.5 In STEP 1, the average loss was 15.3 kg (about 34 lb) over a full 68 weeks, which works out to well under 1 kg a week on average.1

Do you gain weight after stopping semaglutide?

Often, yes. In STEP 4, people switched to placebo after 20 weeks regained 6.9% of body weight by week 68, while those who stayed on semaglutide lost a further 7.9%.6 In the STEP 1 extension (327 people), those who had taken semaglutide regained two-thirds of their prior weight loss within a year of stopping, and heart and metabolic improvements moved back toward baseline.3

Can I qualify for semaglutide?

Eligibility is a prescriber's decision. The Wegovy label covers adults with obesity, adults with overweight plus at least one weight-related condition, and children 12 and older with obesity.2 It also covers adults with heart disease and obesity or overweight, and adults with MASH and moderate to advanced liver fibrosis.2 Ozempic and Rybelsus are for adults with type 2 diabetes.78 STEP 1 required a BMI of 30 or more, or 27 or more with a weight-related condition.1

Is liraglutide better than semaglutide?

Not for weight, in the one direct trial reviewed. In STEP 8 (338 adults with overweight or obesity without diabetes), weekly semaglutide 2.4 mg produced more weight loss than daily liraglutide 3.0 mg over 68 weeks: 15.8% vs 6.4%.9 Fewer people stopped semaglutide (13.5% vs 27.6%), while gastrointestinal side effects were similar (84.1% vs 82.7%).9

Written by D2C Peptides Editorial Team.

Pending qualified review.

Updated .

Sources

  1. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1; Wilding et al.), PubMed abstract PMID 33567185. New England Journal of Medicine (abstract via NLM PubMed E-utilities), 2021.
  2. WEGOVY (semaglutide) injection and tablets prescribing information, section 1 Indications and Usage. DailyMed, U.S. National Library of Medicine (Novo Nordisk label, revised 6/2026), 2026.
  3. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension (Wilding et al.), PubMed abstract PMID 35441470. Diabetes, Obesity and Metabolism (abstract via NLM PubMed E-utilities), 2022.
  4. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity (SURMOUNT-5; Aronne et al.), PubMed abstract PMID 40353578. New England Journal of Medicine (abstract via NLM PubMed E-utilities), 2025.
  5. Same source as 2: section 2 Dosage and Administration.
  6. Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance (STEP 4; Rubino et al.), PubMed abstract PMID 33755728. JAMA (abstract via NLM PubMed E-utilities), 2021.
  7. OZEMPIC (semaglutide) injection prescribing information, Indications and Usage; DailyMed listing. DailyMed, U.S. National Library of Medicine (Novo Nordisk label, revised 5/2026), 2026.
  8. OZEMPIC (semaglutide) tablets and RYBELSUS (semaglutide) tablets prescribing information, Indications and Usage. DailyMed, U.S. National Library of Medicine (Novo Nordisk label, revised 1/2026), 2026.
  9. Effect of Weekly Subcutaneous Semaglutide vs Daily Liraglutide on Body Weight in Adults With Overweight or Obesity Without Diabetes (STEP 8; Rubino et al.), PubMed abstract PMID 35015037. JAMA (abstract via NLM PubMed E-utilities), 2022.
  10. Same source as 2: WEGOVY (semaglutide) prescribing information, sections 12.1 and 12.2 Pharmacodynamics.
  11. STEP 1: Research Study Investigating How Well Semaglutide Works in People Suffering From Overweight or Obesity, NCT03548935. ClinicalTrials.gov, U.S. National Library of Medicine.
  12. Same source as 2: WEGOVY (semaglutide) prescribing information, section 14 Clinical Studies.
  13. Same source as 2: WEGOVY (semaglutide) prescribing information, section 6.1 (dysesthesia, discontinuations).
  14. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (SELECT; Lincoff et al.), PubMed abstract PMID 37952131. New England Journal of Medicine (abstract via NLM PubMed E-utilities), 2023.
  15. FDA approves first treatment to reduce risk of serious heart problems specifically in adults with obesity or overweight. U.S. Food and Drug Administration (press announcement, March 8, 2024), 2024.
  16. Drugs@FDA: WEGOVY tablets, NDA 218316. U.S. Food and Drug Administration.
  17. Same source as 2: WEGOVY (semaglutide) prescribing information, Boxed Warning and Contraindications.
  18. Same source as 2: WEGOVY (semaglutide) prescribing information, Highlights: most common adverse reactions; section 6.1 Table 3.
  19. Warning Letter: Xcel Research LLC (MARCS-CMS 694608), December 10, 2024. U.S. Food and Drug Administration, 2024.
  20. FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss (research-labeled and counterfeit products). U.S. Food and Drug Administration (content current as of 10/01/2026), 2026.