Research goal
Wegovy and weight loss
Wegovy is FDA-approved for long-term weight reduction, always with a reduced-calorie diet and more physical activity.1 The approval covers adults with obesity, or overweight plus a weight-related condition, and (injection only) children 12 and older with obesity.1 In the label's main weight trials of adults without diabetes, average weight change ranged from -13.6% on the tablets to -18.8% on the 7.2 mg injection.1
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What sources report
Wegovy weight loss injections and tablets were tested in placebo-controlled phase 3 trials, which the label summarizes.1 STEP 1, the main injection trial, enrolled adults with a BMI of 30 or more, or 27 or more with a weight-related condition, alongside lifestyle intervention.8 The figures below are trial group averages, and results vary by person.1
Average weight change by trial
| Trial (label study) | Who took part | Length | Wegovy | Placebo |
|---|---|---|---|---|
| STEP 1 (Study 2)1 | 1,961 adults, no diabetes | 68 weeks | -14.9% (2.4 mg) | -2.4% |
| STEP 3 (Study 4)1 | 611 adults on intensive lifestyle therapy | 68 weeks | -16% | -5.7% |
| Study 81 | 1,407 adults with obesity, no diabetes | 72 weeks | -18.8% (7.2 mg); -15.5% (2.4 mg) | -3.9% |
| OASIS 4 (Study 7)1 | 307 adults, no diabetes | 64 weeks | -13.6% (25 mg tablets) | -2.4% |
| STEP 2 (Study 3)1 | 807 adults with type 2 diabetes | 68 weeks | -9.6% | -3.4% |
| Study 91 | 512 adults with type 2 diabetes | 72 weeks | -13.2% (7.2 mg); -10.4% (2.4 mg) | -3.8% |
| STEP TEENS (Study 10)1 | 201 adolescents aged 12 and older | 68 weeks | -14.7% | +2.7% |
| SELECT (Study 1)1 | 17,604 adults with heart disease, no diabetes | to week 104 | -9.4% | -0.9% |
People with type 2 diabetes lost less on average than people without it, at both 2.4 mg and 7.2 mg.1
How many people reached 5%, 10% or 20%
- STEP 1, 2.4 mg, 68 weeks. 83.5% lost at least 5% of body weight (31.1% on placebo), 66.1% at least 10% (12%) and 30.2% at least 20% (1.7%).1
- OASIS 4, 25 mg tablets, 64 weeks. 76.3% lost at least 5% (31.3% on placebo) and 27.9% at least 20% (3.1%).1
- Study 8, 72 weeks. 45.5% on 7.2 mg lost at least 20%, against 32.3% on 2.4 mg.1
Put the other way, 16.5% of people on 2.4 mg in STEP 1 did not reach a 5% loss.1
Keeping weight off
STEP 4 began with a 20-week run-in on semaglutide for 902 adults.2 The 803 who reached 2.4 mg, and had lost 10.6% on average by then, were randomized to continue or to switch to placebo.2 Those who continued lost a further 7.9% by week 68, while those switched to placebo regained 6.9%.1
In the STEP 1 extension, 327 adults were followed for a year after treatment ended.4 Their net change from the start to week 120 was -5.6%, against -0.1% for the former placebo group.4 Most heart and metabolic measures that had improved moved back toward where they began.4
Head-to-head trials
STEP 8 compared weekly semaglutide 2.4 mg with daily liraglutide 3.0 mg in 338 adults without diabetes for 68 weeks.9 Average weight change was -15.8% against -6.4%, and 13.5% against 27.6% stopped treatment.9
SURMOUNT-5 compared tirzepatide with semaglutide, each at its maximum tolerated dose, in 751 adults with obesity and without diabetes for 72 weeks.7 Weight change was -20.2% on tirzepatide (10 or 15 mg) against -13.7% on semaglutide (1.7 or 2.4 mg).7 Waist size fell 18.4 cm against 13.0 cm, and stomach and bowel events were the most common side effects with both.7
What the label says
Wegovy is approved to reduce excess body weight and keep it off long term, always with a reduced-calorie diet and more physical activity.1 The injection's maintenance dose for weight is 2.4 mg (recommended) or 1.7 mg once weekly, reached after a 16-week climb from 0.25 mg.1 After at least 4 weeks on 2.4 mg, adults can move up to 7.2 mg when more weight reduction is clinically indicated.1 Daily tablets reach their 25 mg maintenance dose from day 91.1 The prescriber decides whether Wegovy fits and sets every dose.1
The label also sets limits that matter for weight use.1 The label does not recommend combining Wegovy with other semaglutide products or any other GLP-1 receptor agonist.1 Because weight loss brings no benefit during pregnancy and may harm the fetus, the label says to stop Wegovy at least 2 months before a planned pregnancy.1 For adults with type 2 diabetes, the label reports no weight study of the tablets.1 Nausea, diarrhea and other digestive effects top the side effect list, and the boxed warning concerns thyroid C-cell tumors found in rodents.1
Read next
The Wegovy profile explains the medicine as a whole. Every step of the schedule is in Wegovy dosage, and reported reactions with their rates are in Wegovy side effects. For the other compounds people look up with this goal, go to Peptides and weight loss. The molecule's record across all its brands is in Semaglutide and weight loss, and the brand comparison in Mounjaro vs Wegovy.
Frequently asked questions
How long does it take to lose 20 lbs with Wegovy?
Trials report percent of body weight over months, not the time to reach a set number of pounds, and results vary by person.1 In STEP 4, the 803 adults who completed a 20-week run-in, which included the dose climb, had lost 10.6% of body weight on average.2 In STEP 1, adults on 2.4 mg had lost 14.9% on average by week 68.1 How many pounds a percentage means depends on starting weight, and the prescriber sets the pace of each dose step.1
Why does Wegovy help you lose weight?
Semaglutide, its active ingredient, activates the GLP-1 receptor, including in brain areas that regulate appetite.1 The label says it lowers calorie intake, likely by affecting appetite, and that the weight lost is more fat mass than lean mass.1 It also slows stomach emptying.1 In animal studies, semaglutide reached and activated neurons in brain regions that regulate food intake.3
What happens when you stop taking Wegovy?
Weight tends to come back.14 In the label's withdrawal study, adults switched to placebo after 20 weeks regained 6.9% of body weight by week 68, while those who stayed on Wegovy lost a further 7.9%.1 In the STEP 1 extension, people regained about two-thirds of the weight they had lost within a year of stopping.4 Semaglutide stays in the blood for about 5 to 7 weeks after the last dose.1
Which is better, Wegovy or Mounjaro?
They are approved for different uses.51 Mounjaro is tirzepatide for blood sugar control and heart risk in type 2 diabetes, while Wegovy is semaglutide for weight reduction, heart risk reduction and MASH.51 Zepbound is the tirzepatide brand approved for weight reduction.6 In SURMOUNT-5, a 72-week trial of 751 adults, tirzepatide at its maximum tolerated dose gave an average weight change of -20.2%, against -13.7% for semaglutide at 1.7 or 2.4 mg.7 Which medicine suits a person is the prescriber's call.1 The two brands are set side by side in Mounjaro vs Wegovy.
Written by D2C Peptides Editorial Team.
Pending qualified review.
Updated .
Sources
- WEGOVY (semaglutide) injection and WEGOVY (semaglutide) tablets: Full Prescribing Information, Medication Guide and Instructions for Use (revised 06/2026). U.S. Food and Drug Administration (Novo Nordisk labeling), 2026.
- 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.
- WEGOVY (semaglutide) prescribing information, sections 12.1 and 12.2 Pharmacodynamics. DailyMed, U.S. National Library of Medicine (Novo Nordisk label, revised 6/2026), 2026.
- 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.
- MOUNJARO (tirzepatide) injection, prescribing information (revised 8/2026). U.S. National Library of Medicine, DailyMed (label by Eli Lilly), 2026.
- ZEPBOUND (tirzepatide) injection, prescribing information (revised 8/2026). U.S. National Library of Medicine, DailyMed (label by Eli Lilly), 2026.
- 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.
- 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.
- 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.