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Benefits and uses

Semaglutide benefits and uses

In large randomized trials of semaglutide, average weight change was -14.9% vs -2.4% on placebo at 68 weeks, major heart events in adults with heart disease occurred in 6.5% vs 8.0%, and the liver disease MASH resolved without worse fibrosis in 62.9% vs 34.3%.123 These are group averages, not promises, and weight tends to return after stopping.4

This page summarizes published sources for information only. It is not medical advice and does not tell anyone to use a product. Questions about your own health belong with a licensed clinician. For questions about an order or a product, contact us.

Semaglutide before and after: what trials measured

In the sources used here, semaglutide before and after means trial data, not photos: none of them contains individual photos or testimonials. What they report are average changes from the start of a trial to its end, compared with placebo or another drug, and the main ones are below.

Outcome Study Semaglutide Placebo or comparator
Body weight STEP 1: 1,961 adults, 68 weeks1 -14.9% (-15.3 kg) -2.4% (-2.6 kg)
Waist size SURMOUNT-5: 751 adults with obesity, 72 weeks8 -13.0 cm -18.4 cm with tirzepatide
HbA1c in type 2 diabetes Ozempic label: 30-week trial6 -1.4 to -1.6 points -0.1 points
Major cardiovascular events SELECT: 17,604 adults, mean 39.8 months2 6.5% 8.0%
Main kidney outcome FLOW: 3,533 people, median 3.4 years5 24% lower risk Reference group
MASH resolved, fibrosis not worse ESSENCE: 800 people, 72 weeks3 62.9% 34.3%

Each row is a group average. In STEP 1, 86.4% of people on semaglutide lost at least 5% of their body weight and 50.5% lost at least 15%, vs 31.5% and 4.9% on placebo.1 More on Semaglutide and weight loss. Blood sugar and kidney results are detailed on Semaglutide and blood sugar.

Body composition

The Wegovy label states that semaglutide lowers body weight with greater fat mass loss than lean mass loss, so some lean mass is lost as well.9 In SURMOUNT-5, average waist size fell 13.0 cm over 72 weeks on semaglutide, while tirzepatide produced a larger fall of 18.4 cm.8

Heart

SELECT enrolled 17,604 adults aged 45 or older with existing cardiovascular disease, a BMI of 27 or more and no history of diabetes.2 They were followed for a mean of 39.8 months.2 A major cardiovascular event (cardiovascular death, nonfatal heart attack or nonfatal stroke) occurred in 6.5% on semaglutide vs 8.0% on placebo, a hazard ratio of 0.80.2 On that evidence, FDA approved Wegovy on March 8, 2024 to lower the risk of serious heart problems in adults with obesity or overweight and heart disease.11 The label says the exact mechanism of this benefit has not been established.12 Ozempic's label separately covers lowering major cardiovascular event risk in adults with type 2 diabetes and established cardiovascular disease.10

Liver

ESSENCE enrolled people with biopsy-confirmed metabolic dysfunction-associated steatohepatitis (MASH) and stage 2 or 3 liver fibrosis.3 In the first 800 patients, semaglutide 2.4 mg weekly resolved steatohepatitis without worsening fibrosis in 62.9% vs 34.3% on placebo at 72 weeks.3 It also improved fibrosis without worsening steatohepatitis in 36.8% vs 22.4%.3

FDA approved this use for Wegovy as an accelerated approval, so continued approval may depend on a confirmatory trial.13 The EU authorised a semaglutide injection for the same disease under the name Kayshild on 26 March 2026.14 The label says the mechanism in MASH is not fully understood and may involve weight loss and other pathways.12

What happens after stopping

In the STEP 1 extension, people who stopped semaglutide regained two-thirds of their lost weight within a year, and most heart and metabolic markers moved back toward baseline; the authors concluded that ongoing treatment is needed to keep the improvements.4 More on Semaglutide and weight loss.

What is not established

  • Skin and hair: no source reviewed here reports a benefit, and hair loss is a listed side effect, reported by 3.3% on 2.4 mg vs 1% on placebo.15
  • Brain health: no source reviewed here shows a cognitive benefit. EVOKE, a phase 3 trial of oral semaglutide in 1,840 people with early Alzheimer's disease, was completed on January 30, 2026, and its registry record showed no posted results as of October 2026.16
  • Research vials: every result on this page comes from trials and labels of semaglutide medicines, not from research-labeled vials; FDA says unapproved versions do not undergo its review for safety, effectiveness and quality.17

Back to What is Semaglutide?. The trade-offs are on Semaglutide side effects, the doses behind these results on Semaglutide dosage, and vial handling on How to reconstitute Semaglutide. For the class as a whole, see GLP-1 benefits and uses.

More on Semaglutide

  • Semaglutide side effects

    Side effects of Semaglutide as reported in labels, trials and published studies, with links to the full profile. Reviewed by a qualified reviewer.

  • Semaglutide dosage

    Published dosing information for Semaglutide from labels and studies, with its source, and why it is not advice for you.

  • How to reconstitute Semaglutide

    How Semaglutide is reconstituted, the supplies used, and the calculator, step by step. Sourced and reviewed.

Frequently asked questions

What are the benefits of semaglutide besides weight loss?

In SELECT, adults with heart disease and overweight or obesity, but no diabetes, had fewer major cardiovascular events (6.5% vs 8.0% over a mean of 39.8 months).2 In FLOW, people with type 2 diabetes and chronic kidney disease had a 24% lower risk of the main kidney outcome.5 HbA1c fell 1.4 to 1.6 points vs 0.1 on placebo in a 30-week diabetes trial, and in ESSENCE the liver disease MASH resolved in 62.9% vs 34.3% at 72 weeks.63 These are group averages, not guaranteed results.

What does semaglutide do to your body long term?

SELECT, one of the longest large trials, followed 17,604 adults for a mean of 39.8 months.2 It found fewer major cardiovascular events (6.5% vs 8.0%), while 16.6% stopped the drug because of adverse events vs 8.2% on placebo.2 Benefits fade after stopping: two-thirds of lost weight returned within a year in the STEP 1 extension.4 Whether the thyroid C-cell tumors seen in rodents apply to people is still unknown.7

Will semaglutide get rid of my belly fat?

No source reviewed here shows semaglutide targeting fat in one body area. In SURMOUNT-5, waist size fell by an average of 13.0 cm over 72 weeks with semaglutide.8 The Wegovy label says semaglutide lowers body weight with greater fat mass loss than lean mass loss.9 Those are averages across hundreds of people, and individual results vary.

Does semaglutide cause muscle loss?

Some lean mass is lost along with fat. The Wegovy label states that semaglutide lowers body weight with greater fat mass loss than lean mass loss, and it does not describe semaglutide as building muscle.9 Compounds studied for muscle are compared on Peptides and muscle growth.

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. 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.
  3. Phase 3 Trial of Semaglutide in Metabolic Dysfunction-Associated Steatohepatitis (ESSENCE; Sanyal et al.), PubMed abstract PMID 40305708. New England Journal of Medicine (abstract via NLM PubMed E-utilities), 2025.
  4. 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.
  5. Effects of Semaglutide on Chronic Kidney Disease in Patients with Type 2 Diabetes (FLOW; Perkovic et al.), PubMed abstract PMID 38785209. New England Journal of Medicine (abstract via NLM PubMed E-utilities), 2024.
  6. OZEMPIC (semaglutide) injection prescribing information, section 14 Clinical Studies. DailyMed, U.S. National Library of Medicine (Novo Nordisk label, revised 5/2026), 2026.
  7. Same source as 6: Boxed Warning.
  8. 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.
  9. 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.
  10. Same source as 6: Indications and Usage; DailyMed listing.
  11. 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.
  12. Same source as 9: section 12.1 Mechanism of Action.
  13. Same source as 9: WEGOVY (semaglutide) injection and tablets prescribing information, section 1 Indications and Usage.
  14. Kayshild: EPAR medicine overview. European Medicines Agency, 2026.
  15. Same source as 9: section 6.1 (hair loss).
  16. A Research Study Investigating Semaglutide in People With Early Alzheimer's Disease (EVOKE), NCT04777396. ClinicalTrials.gov, U.S. National Library of Medicine.
  17. FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss (compounded drugs). U.S. Food and Drug Administration (content current as of 10/01/2026), 2026.