Semaglutide
Semaglutide copies the gut hormone GLP-1. It is sold as a weekly injection and, since late 2025, as a daily pill for weight management.
Brand names: Wegovy, Wegovy HD, Wegovy pill, Ozempic, Rybelsus
Semaglutide (known as Ozempic, Wegovy, Wegovy HD, Rybelsus)
Also searched as: GLP-1 pill, GLP-1 shot, oral Wegovy, oral semaglutide, sema, semaglutide injection, semeglutide, semiglutide, weight loss pill.
Educational information. This page does not give dosing instructions or tell you what to take. Ask a prescriber about your own care.
In plain English
Semaglutide is a lab-made version of a hormone your gut releases after you eat. That hormone, GLP-1, tells the brain you are full, slows the stomach so food leaves it more gradually, and helps the pancreas release insulin when blood sugar is high.
The same molecule is sold under different brand names for different conditions. Wegovy is the brand approved for weight management. Ozempic and Rybelsus are approved for type 2 diabetes. The injection is taken once a week. The weight-management pill is taken once a day.
Brand names and products
A generic name identifies the drug itself. A brand name identifies one company's product. One drug can come in several products with different forms and approved uses, so the brand name often tells you more about what a prescription is for.
| Brand name | Maker | Form | U.S. approved use | Status |
|---|---|---|---|---|
| Wegovy | Novo Nordisk | Weekly injection | Weight management | FDA-approved for weight management |
| Wegovy HD | Novo Nordisk | Weekly injection (higher strength) | Weight management | FDA-approved for weight management |
| Wegovy pill | Novo Nordisk | Daily tablet | Weight management | FDA-approved for weight management |
| Ozempic | Novo Nordisk | Weekly injection | Type 2 diabetes | FDA-approved, but not for obesity |
| Rybelsus | Novo Nordisk | Daily tablet | Type 2 diabetes | FDA-approved, but not for obesity |
Approved and investigational. Each product above is approved only for the use shown. A product approved for type 2 diabetes is not approved for weight management. This page covers approved products. Other uses of semaglutide, other forms and other doses may be under study. This atlas has not recorded them, so none are described here.
How it works
Semaglutide activates the GLP-1 receptor. In the brain this reduces appetite and food intake. In the gut it slows gastric emptying. In the pancreas it raises insulin and lowers glucagon when glucose is high.
Forms and approval status
| Form | How it is taken | U.S. status |
|---|---|---|
| Semaglutide injection (Wegovy) | Once weekly. Weekly injection. Follow the label and your prescriber for how to use it. | Approved in the U.S. for weight reduction in adults with obesity, or overweight plus a weight-related condition, and in children 12 and older with obesity. Also approved to lower cardiovascular risk in some adults and to treat MASH with liver scarring. Used with diet and activity. A higher-strength injection, Wegovy HD, was approved in March 2026 for the same weight-reduction purpose. |
| Oral semaglutide for weight management (Wegovy pill) | Once daily. Per the label, the tablet is taken once a day in the morning on an empty stomach, with plain water (up to 4 ounces), and swallowed whole. The label says to wait at least 30 minutes before eating, drinking anything else or taking other oral medicines. | Approved in the U.S. for weight reduction in adults with obesity, or overweight plus a weight-related condition, and to lower cardiovascular risk in some adults. The tablet label does not include the injection's uses in children or for MASH. Used with diet and activity. Trade press dates the approval to December 2025. |
What the trials found
These are group averages from published trials in adults without diabetes unless stated. See how to read trial numbers before comparing.
STEP 1
Average change in body weight. Every bar uses one scale, 0 to 25 percent.
- People studied
- 1,961 adults with obesity, or overweight plus at least one weight-related condition, without diabetes
- Length
- 68 weeks
- Compared with
- Placebo, with lifestyle support in both groups
- What was measured
- Average change in body weight at week 68
- Analysis approach
- Regardless of treatment discontinuation or rescue treatment
- Other results
- Weight loss of at least 5%: 86.4% with semaglutide vs 31.5% with placebo. At least 10%: 69.1% vs 12.0%. At least 15%: 50.5% vs 4.9%.
- Safety
- Nausea and diarrhea were the most common side effects. Stopping treatment because of gastrointestinal events: 4.5% vs 0.8%.
- Limits
- Funded by the manufacturer. Participants did not have diabetes. Group averages do not predict one person's result.
Sources: Wilding JPH 2021
STEP 5
Average change in body weight. Every bar uses one scale, 0 to 25 percent.
- People studied
- 304 adults with obesity, or overweight plus at least one weight-related condition, without diabetes
- Length
- 104 weeks
- Compared with
- Placebo, with a behavioral program in both groups
- What was measured
- Average change in body weight at week 104
- Analysis approach
- Regardless of treatment discontinuation or rescue treatment
- Other results
- Weight loss of at least 5%: 77.1% vs 34.4%.
- Safety
- Gastrointestinal events, mostly mild to moderate, were reported by 82.2% with semaglutide and 53.9% with placebo.
- Limits
- A smaller trial than STEP 1. Funded by the manufacturer, and some authors work for the company.
Sources: Garvey WT 2022
OASIS 4
Average change in body weight. Every bar uses one scale, 0 to 25 percent.
- People studied
- 307 adults with obesity, or overweight plus at least one obesity-related complication, without diabetes (205 oral semaglutide, 102 placebo)
- Length
- 64 weeks
- Compared with
- Placebo once daily, with lifestyle support in both groups
- What was measured
- Estimated average change in body weight at week 64
- Analysis approach
- Not stated in the abstract. Check the full paper.
- Other results
- More people on oral semaglutide reached weight reductions of at least 5%, 10%, 15% and 20%. A trade-press report cites 16.6% vs 2.7% for time on treatment. That is a different analysis from the abstract's figures, so check which one a number comes from.
- Safety
- Gastrointestinal adverse events: 74.0% with oral semaglutide vs 42.2% with placebo.
- Limits
- A smaller trial than the injectable semaglutide program. Funded by the manufacturer.
Sources: Wharton S 2025, FDA approves Wegovy pill, the first oral GLP-1 to treat obesity
SURMOUNT-5
Average change in body weight. Every bar uses one scale, 0 to 25 percent.
- People studied
- 751 adults with obesity but without type 2 diabetes
- Length
- 72 weeks
- Compared with
- Semaglutide, head to head. Open label, so participants and staff knew which drug was used. No placebo group.
- What was measured
- Average percent change in body weight at week 72
- Analysis approach
- Least-squares mean change from baseline to week 72, as reported in the abstract.
- Other results
- Waist circumference fell 18.4 cm with tirzepatide vs 13.0 cm with semaglutide. More people on tirzepatide reached weight loss of at least 10%, 15%, 20% and 25%.
- Safety
- Gastrointestinal effects were the most common side effects in both groups. Most were mild to moderate and happened mainly while the dose was being raised.
- Limits
- Funded by Eli Lilly, the maker of tirzepatide. Open label. Each person took the highest dose they could tolerate, so the doses were not identical across people. Group averages do not predict one person's result.
Sources: Aronne LJ 2025
STEP 8
Average change in body weight. Every bar uses one scale, 0 to 25 percent.
- People studied
- 338 adults with obesity, or overweight plus a weight-related condition, without diabetes, at 19 U.S. sites
- Length
- 68 weeks
- Compared with
- Daily liraglutide 3.0 mg and a pooled placebo group. Semaglutide and liraglutide were compared open label.
- What was measured
- Average percent change in body weight at week 68
- Analysis approach
- Mean change from baseline. The placebo comparison was a supportive secondary result.
- Other results
- Weight loss of at least 10%: 70.9% with semaglutide vs 25.6% with liraglutide. At least 15%: 55.6% vs 12.0%. At least 20%: 38.5% vs 6.0%.
- Safety
- Gastrointestinal events: 84.1% with semaglutide vs 82.7% with liraglutide. Stopping treatment for any reason: 13.5% vs 27.6%.
- Limits
- The two active drugs were compared open label. Several authors work for Novo Nordisk, which makes semaglutide. Group averages do not predict one person's result.
Sources: Rubino DM 2022
STEP UP
Average change in body weight. Every bar uses one scale, 0 to 25 percent.
- People studied
- 1,407 adults with a body mass index of 30 or higher, without diabetes; average weight 113 kg and 73.7% were women
- Length
- 72 weeks
- Compared with
- Semaglutide 2.4 mg and placebo, with a lifestyle program in all groups
- What was measured
- Average percent change in body weight at week 72
- Analysis approach
- Treatment-policy estimand: effects regardless of whether people stayed on treatment.
- Other results
- On average the 7.2 mg group lost 3.1 percentage points more than the 2.4 mg group (95% confidence interval for the difference: 1.6 to 4.7 points).
- Safety
- Gastrointestinal events: 70.8% with 7.2 mg, 61.2% with 2.4 mg and 42.8% with placebo. Altered skin sensation (dysaesthesia): 22.9%, 6.0% and 0.5%. Serious adverse events: 6.8%, 10.9% and 5.5%.
- Limits
- Funded by Novo Nordisk. Participants did not have diabetes. Group averages do not predict one person's result.
Sources: Wharton S 2025, Wegovy HD (semaglutide 7.2 mg) approved in the US, providing 20.7% mean weight loss
Safety
Based on the FDA-approved label for Wegovy (injection and tablets). The official label is the controlling source for warnings. The points below are a summary and may be incomplete.
Boxed warning and label notes
- Semaglutide injection (Wegovy): Boxed warning: risk of thyroid C-cell tumors. In rodents semaglutide causes these tumors, and it is unknown whether it does in humans. Not for people with a personal or family history of medullary thyroid carcinoma or MEN 2.
- Oral semaglutide for weight management (Wegovy pill): Boxed warning: risk of thyroid C-cell tumors. The label covers the injection and the tablets together. Not for people with a personal or family history of medullary thyroid carcinoma or MEN 2.
Warnings labels describe
- The Wegovy label carries a boxed warning: in rodents semaglutide causes thyroid C-cell tumors, and it is unknown whether it does in humans. It is contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2, and after a serious allergic reaction to semaglutide.
- The label's warnings and precautions list acute pancreatitis, acute gallbladder disease, low blood sugar, kidney injury from dehydration, severe stomach and bowel reactions, allergic reactions, diabetic retinopathy complications in people with type 2 diabetes, increased heart rate, and aspiration during anesthesia or deep sedation.
- For weight management, the label says to stop the medicine when pregnancy is recognized, because weight loss offers no benefit in pregnancy and may harm the fetus. Anyone planning a pregnancy should talk to their prescriber.
- The label says the medicine slows stomach emptying and may change how other oral medicines are absorbed. In a study with the tablet, levothyroxine exposure rose by 33%. Anyone taking other oral medicines should ask their prescriber.
- The label says using it with other semaglutide products or any other GLP-1 receptor agonist is not recommended.
Most common in trials
- Nausea
- Diarrhea
- Vomiting
- Constipation
- Abdominal pain
Less common but serious
- Pancreatitis
- Gallbladder problems
- Dehydration with kidney injury
- Severe allergic reactions
- Diabetic retinopathy complications in people with type 2 diabetes
What is still unknown
- How much weight returns after stopping, and how that varies between people.
- How well the benefits hold over many years in people outside the trial populations.
- How the pill compares with the injection in a head-to-head trial.
Compiled from public information: FDA-approved labels, manufacturer websites, ClinicalTrials.gov and published journal articles. Sources are listed at the bottom of this page.
Sources
- Wegovy (semaglutide) injection and tablets: prescribing information Novo Nordisk, on DailyMed (U.S. National Library of Medicine). Label version 6/2026. One label covers both the injection and the tablets. Official FDA label on DailyMed
- DailyMed: current FDA drug labels U.S. National Library of Medicine. Regulator
- Drugs@FDA: approved drug products U.S. Food and Drug Administration. Regulator
- Effect of weekly subcutaneous semaglutide vs daily liraglutide on body weight in adults with overweight or obesity without diabetes (STEP 8) Rubino DM, et al. JAMA. 2022;327(2):138-150. PMID 35015037. Funding: Novo Nordisk. Journal article
- Once-weekly semaglutide 7.2 mg in adults with obesity (STEP UP) Wharton S, et al. Lancet Diabetes Endocrinol. 2025;13(11):949-963. PMID 40961952. Funding: Novo Nordisk. Journal article
- Wegovy HD (semaglutide 7.2 mg) approved in the US, providing 20.7% mean weight loss Novo Nordisk company announcement, March 19, 2026. Company announcement; not peer reviewed. Company announcement, not peer reviewed
- FDA approves Novo Nordisk's Wegovy pill Pharmaceutical Commerce, December 2025. Trade press, secondary source
- FDA approves Wegovy pill, the first oral GLP-1 to treat obesity Healio. Trade press. Reports on-treatment OASIS 4 figures and how the pill is taken. Not the label. Trade press, secondary source
- Mechanisms of action and therapeutic application of glucagon-like peptide-1 Drucker DJ. Cell Metab. 2018;27(4):740-756. PMID 29617641. Journal article
- Once-weekly semaglutide in adults with overweight or obesity (STEP 1) Wilding JPH, et al. N Engl J Med. 2021;384(11):989-1002. PMID 33567185. Funding: Novo Nordisk. Journal article
- Two-year effects of semaglutide in adults with overweight or obesity (STEP 5) Garvey WT, et al. Nat Med. 2022;28(10):2083-2091. PMID 36216945. Funding: Novo Nordisk (authors include company employees). Journal article
- Oral semaglutide at a dose of 25 mg in adults with overweight or obesity (OASIS 4) Wharton S, et al. N Engl J Med. 2025;393(11):1077-1087. PMID 40934115. Funding: Novo Nordisk. Journal article
- Tirzepatide as compared with semaglutide for the treatment of obesity (SURMOUNT-5) Aronne LJ, et al. N Engl J Med. 2025;393(1):26-36. PMID 40353578. Funding: Eli Lilly. Journal article
- Ozempic (semaglutide) injection: prescribing information Novo Nordisk, on DailyMed (U.S. National Library of Medicine). Label version 6/2026. Official FDA label on DailyMed
- Rybelsus (semaglutide) tablets: prescribing information Novo Nordisk, on DailyMed (U.S. National Library of Medicine). Label version 10/2025. Official FDA label on DailyMed