At a glance: GLP-1 drug approved for type 2 diabetes and weight management. Evidence: Large phase 3 trials. Status: FDA-approved (prescription).
How it works
Semaglutide copies GLP-1, a hormone your gut releases after eating. It makes you feel full sooner, slows how fast the stomach empties, and helps the pancreas release insulin when blood sugar is high.
It is sold under three brand names: Ozempic (weekly injection for type 2 diabetes), Wegovy (weekly injection for weight management) and Rybelsus (a daily tablet for type 2 diabetes).
How it’s taken
Wegovy and Ozempic are once-a-week injections under the skin, in the belly, thigh or upper arm, on the same day each week, with or without food. Rybelsus is a daily tablet taken on an empty stomach with a sip of water.
Approved dosing
Every patient starts low and steps up every 4 weeks. This is the Wegovy schedule from the FDA label:
| Weeks | Dose once a week |
|---|---|
| 1–4 | 0.25 mg |
| 5–8 | 0.5 mg |
| 9–12 | 1 mg |
| 13–16 | 1.7 mg |
| 17 onward | 2.4 mg (maintenance) |
For adult weight reduction the dose can go up to 7.2 mg if 2.4 mg has been tolerated for at least 4 weeks and more weight loss is needed. 1.7 mg is an alternative maintenance dose.
What the research shows
- Weight: average loss around 15% of body weight over 68 weeks in the main obesity trial.
- Heart: lower risk of heart attack, stroke and cardiovascular death in people with heart disease and obesity.
- Blood sugar: large reductions in A1C in type 2 diabetes.
- Liver: approved under accelerated approval for MASH (a fatty liver disease) with moderate to advanced fibrosis.
Side effects
Mostly stomach-related, and worst during dose increases.
| Side effect | On 2.4 mg | On placebo |
|---|---|---|
| Nausea | 44% | 16% |
| Diarrhea | 30% | 16% |
| Vomiting | 24% | 6% |
| Constipation | 24% | 11% |
| Abdominal pain | 20% | 10% |
| Headache | 14% | 10% |
| Fatigue | 11% | 5% |
From the Wegovy FDA label.
Boxed warning: semaglutide caused thyroid C-cell tumors in rodents. It should not be used by anyone with a personal or family history of medullary thyroid cancer or MEN 2 syndrome. Get medical help right away for severe ongoing stomach pain (a sign of pancreatitis).
Frequently asked questions
What is Semaglutide?
A long-acting version of the GLP-1 hormone, which affects blood sugar and appetite.
How is Semaglutide taken?
Weekly subcutaneous injection; daily oral tablet (Rybelsus).
Is Semaglutide FDA approved?
FDA-approved (prescription).
What has research shown about Semaglutide?
- Blood sugar control in type 2 diabetes.
- Weight loss in large clinical trials.
- Lower risk of heart attack and stroke in people with heart disease and excess weight.
What side effects have been reported?
- Nausea (44%)
- Diarrhoea (30%)
- Vomiting (24%)
- Constipation (24%)
- Abdominal pain (20%)
- Headache (14%)
- Fatigue (11%)
Serious or less common risks are listed in the Side Effects section above.
What is still unknown about its safety?
Side effects that are rare, or that only appear after many years of use, are still being tracked through post-marketing surveillance. Talk to a prescriber about your own risk.
References
- Wegovy (semaglutide) FDA label, DailyMed View source