Semaglutide

Products and approved uses

The June 2026 US Wegovy label covers injections and tablets with different approved uses. The injection also has an accelerated-approval MASH indication. The label lists the exact indication for each product and population.⁶

Who the trials studied

STEP 1 excluded diabetes. SELECT enrolled people with existing cardiovascular disease. FLOW required both type 2 diabetes and chronic kidney disease.^1,3,4

Alzheimer's disease

In 2026, EVOKE and EVOKE+ did not slow clinical progression in early Alzheimer's disease.⁵

Weight loss results

STEP 1 studied 1,961 adults with overweight or obesity and no diabetes, over 68 weeks. Both groups received lifestyle intervention.¹

Semaglutide		14.9%
Placebo		2.4%

% of starting body weight. Once-weekly subcutaneous semaglutide 2.4 mg was compared with placebo in the trial.¹

Average weight loss

Mean weight changed by -14.9% with semaglutide and -2.4% with placebo. The adjusted difference was -12.4 percentage points (95% CI -13.4 to -11.5). Individual results varied. Novo Nordisk funded the trial.¹

After treatment stopped

An exploratory extension followed 327 participants after both study treatment and lifestyle support ended at week 68. One year later, the group previously taking semaglutide had regained about two-thirds of its earlier weight loss.²

Heart, kidney and Alzheimer's trials

Heart, kidney and Alzheimer's outcomes in the trial populations.

6.5% vs 8.0%

Major cardiovascular events with semaglutide versus placebo. SELECT enrolled 17,604 adults with existing cardiovascular disease, BMI at least 27 and no diabetes; mean follow-up was 39.8 months. Hazard ratio 0.80 (95% CI 0.72-0.90).³

The rounded absolute difference was 1.5 percentage points over follow-up. The hazard ratio expresses a relative reduction rather than a 20-percentage-point absolute reduction. Adverse events led to permanent discontinuation in 16.6% versus 8.2%.³

331 vs 410 events

The first major kidney event, kidney-related death or cardiovascular death occurred in 331/1,767 people (18.7%) with semaglutide and 410/1,766 (23.2%) with placebo. The crude difference was 4.5 percentage points over a median 3.4 years. Hazard ratio 0.76 (95% CI 0.66-0.88) is a relative time-to-event measure. The trial ended early after a prespecified interim analysis.⁴

Alzheimer's disease

EVOKE and EVOKE+ randomized 3,808 adults aged 55-85 with amyloid-confirmed early Alzheimer's disease. Oral semaglutide up to 14 mg daily did not significantly improve the primary clinical progression score at week 104 versus placebo. Both trials were discontinued.⁵

Novo Nordisk funded SELECT, FLOW and EVOKE / EVOKE+. Each result is specific to its study population and regimen.^3,4,5

Safety

This page summarizes selected risks. An individual assessment combines the current product label with clinical context.

Digestive side effects

Digestive symptoms are common. The Wegovy label also warns about pancreatitis, gallbladder disease, kidney injury from dehydration and severe gastrointestinal reactions. It does not recommend Wegovy for severe gastroparesis.⁶

Thyroid warning

Semaglutide caused thyroid C-cell tumors in rodents. Its relevance to people is unknown. The US label says not to use Wegovy with a personal or family history of medullary thyroid carcinoma, MEN 2, or a prior serious allergic reaction to semaglutide or a Wegovy ingredient.⁶

Other medicines and procedures

Using Wegovy with insulin or a sulfonylurea may raise the risk of low blood sugar. Relevant clinical context includes diabetic retinopathy, pregnancy plans, other medicines and upcoming anesthesia or sedation.⁶

The current US label and EMA notice answer different regulatory questions.

Product quality

Trial results apply to the medicine that was tested. This section covers product identity, amount and contamination.

Small online-purchase study

Researchers attempted six online purchases. Three freeze-dried vials arrived for testing; none of the three supposed Ozempic pens arrived. The vials contained about 29-39% more semaglutide than their labels stated, and one had elevated endotoxin. Because the sellers were selected as high risk, the sample was not representative of the whole market.^8,9

One study, two papers

The JAMA Network Open paper and the longer JMIR paper cover the same test purchases. They are not two independent studies or six separately tested vials.^8,9

Test findings and limits

The papers also report low measured purity. The longer analysis found no peptide-like impurities and could not identify the remaining substances. Its abstract and main text describe the endotoxin results differently. The amount on the label was clearly wrong, but the study does not support a blanket claim that the rest was dangerous contamination.⁹

Questions for your clinician

The exact product name, your medical history and the outcome you care about frame this discussion. These studies describe groups, not your personal result.

Which study population resembles me?

Did the study include people with my diagnosis, age and risk profile? Did it measure weight, cardiovascular events, kidney outcomes or something else?

What counts as a meaningful benefit for me?

Which outcome will we track, for how long, and what result would make us reconsider? What is the absolute benefit beside the risk of side effects?

What needs a plan before treatment?

How do my other medicines, eye history, digestive symptoms, pregnancy plans or upcoming procedures affect the plan? Which symptoms need prompt care?

What if I need to stop?

Discuss side effects, access and what may happen after stopping.²

Common questions about semaglutide

Answers based on the studies, labels and regulator notices cited below.

01 Does it work as well if I have type 2 diabetes?

STEP 2 enrolled adults with type 2 diabetes. With the studied 2.4 mg weekly injection, average weight loss was 9.6% versus 3.4% with placebo at 68 weeks. STEP 1, which excluded diabetes, showed more average weight loss. Because these were separate trials, they cannot show how much of the difference came from diabetes itself.^10,1

02 Does tirzepatide cause more weight loss than semaglutide?

In the direct SURMOUNT-5 trial, yes on average. Adults with obesity and no diabetes lost 20.2% with tirzepatide and 13.7% with semaglutide over 72 weeks. The Lilly-funded study was open label and used the highest tolerated trial doses. The comparison did not include semaglutide 7.2 mg or predict which medicine will suit one person.¹¹

03 Is losing 15% guaranteed?

No. The 14.9% result from STEP 1 was the group average after 68 weeks. People lost different amounts, and the trial included lifestyle support.¹

04 Has it been tested for painful knee arthritis?

STEP 9 studied people with both obesity and knee osteoarthritis. Over 68 weeks, semaglutide improved pain and weight more than placebo. The trial did not show cartilage repair or the same benefit in people without obesity. Weight change and pain improvement happened together.¹²

05 Can semaglutide cause sudden vision loss?

European and UK regulators list NAION, an optic-nerve condition that can cause sudden vision loss, as a very rare side effect of semaglutide medicines. NAION is different from diabetic retinopathy. Sudden vision loss or rapidly worsening sight needs urgent medical care. This was the European and UK position on September 29, 2026. The US labels available that day did not carry the same warning.^7,13

06 Does a side-effect report prove the medicine caused it?

No. Adverse-event systems collect reports of suspected side effects after treatment. Reports can be incomplete or duplicated, and the number of exposed people is usually unknown. They can flag a signal, but they cannot prove cause or show what percentage of users are affected.¹⁴

07 Is compounded semaglutide the same as an approved medicine?

No equivalence has been shown. Compounded drugs are not FDA-approved, and FDA does not check their safety, effectiveness or quality before marketing. FDA has also warned about dosing errors and products made with semaglutide sodium or acetate, which are different active ingredients from those in approved medicines. Legal status and enforcement rules are date-specific.¹⁴

08 Have products sold online actually been tested?

Researchers tried to buy six products from high-risk sellers and received three, all vials. The published sample was small and deliberately selected. Two papers cover the same three products, so they are not independent replications. The tests found label and quality problems but cannot show how common those problems are across all semaglutide products.^8,9

09 Has semaglutide been studied in people with type 1 diabetes?

Yes, in small trials used with automated insulin delivery. Participants kept taking insulin; semaglutide did not replace it. The crossover trial reported euglycemic ketosis. These studies do not support semaglutide as an insulin substitute, and this studied use is separate from approved uses.^15,16

10 Do adult weight-loss results apply to teenagers?

Teenagers have a separate trial. STEP TEENS enrolled 201 adolescents aged 12 to under 18. It measured percentage change in BMI, while the adult trials measured percentage change in body weight. BMI fell 16.1% with semaglutide and rose 0.6% with placebo at 68 weeks. Those measures are not interchangeable.¹⁷

11 Does a higher dose always mean a better result?

Among adults with obesity and no diabetes in STEP UP, average weight loss was 18.7% with 7.2 mg and 15.6% with 2.4 mg at 72 weeks in the reported treatment-policy analysis. A higher studied dose also changes the side-effect tradeoff. These figures describe the trial comparison.^18,19

12 Are milligrams, milliliters and syringe units interchangeable?

No. Milligrams are the drug amount. Milliliters are liquid volume. Syringe units depend on the device and do not tell you the drug concentration. FDA has reports of serious errors with compounded semaglutide vials. A general conversion chart cannot replace the exact prescription, concentration and device instructions.¹⁴

13 Will everyone regain all the weight?

No. In the STEP 1 extension, participants regained about two-thirds of their earlier semaglutide-associated weight loss over the next year, on average. The medication and the trial's lifestyle program had both stopped. Only a subset of the original trial took part.²

14 Does that study prove tapering prevents weight regain?

No. The STEP 1 extension observed people after treatment stopped; it did not compare tapering schedules. STEP 4 compared continued semaglutide with a switch to placebo after a run-in. Neither trial tested tapering, cycling or intermittent use.^2,20

15 Is losing lean mass the same as losing that much muscle?

No. DXA lean mass includes skeletal muscle, body water and other tissue. The exploratory STEP 1 substudy measured body composition. It did not set a universal percentage of muscle loss or show that strength fell by the same amount.²¹

16 Were heart benefits shown in people without diabetes?

Yes, in SELECT. Participants had existing cardiovascular disease and overweight or obesity. Major cardiovascular events occurred in 6.5% with semaglutide and 8.0% with placebo. The 20% relative reduction is not a 20-percentage-point reduction. This group is different from healthy people using it for prevention.³

17 Does the tablet have cardiovascular outcome evidence too?

Yes. SOUL studied oral semaglutide in adults aged 50 or older with type 2 diabetes, atherosclerotic cardiovascular disease, chronic kidney disease, or both. Major cardiovascular events occurred in 12.0% with semaglutide and 13.8% with placebo. The result applies only to this oral product and study group.²²

18 What did the heart-failure studies actually improve?

STEP-HFpEF improved symptoms, physical limits and walking performance in adults with obesity and heart failure with preserved ejection fraction. It did not show a survival benefit or a benefit in every type of heart failure. A separate trial studied people who also had type 2 diabetes.^23,24

19 Has it helped walking problems from poor circulation?

STRIDE studied adults with type 2 diabetes, peripheral artery disease and intermittent claudication. Over 52 weeks, semaglutide improved maximum treadmill walking distance versus placebo.²⁵

20 Does FLOW prove kidney protection for everyone?

No. FLOW enrolled people with both type 2 diabetes and chronic kidney disease. A smaller SMART trial in people with overweight or obesity and chronic kidney disease but no diabetes found less albumin in urine over 24 weeks. Urine albumin is a marker. That smaller trial did not show the same long-term kidney outcomes as FLOW.^4,26

21 Does a better liver biopsy mean liver failure has been prevented?

Not from the reported ESSENCE interim analysis. At 72 weeks, it measured MASH resolution and fibrosis improvement on biopsy in people with F2 or F3 fibrosis. Those results are different from preventing liver failure, transplant or death.²⁷

22 Did semaglutide work for Alzheimer’s disease?

No benefit was shown. EVOKE and EVOKE+ were large randomized trials of oral semaglutide in people with amyloid-confirmed early Alzheimer's disease. The trials did not slow measured clinical decline over 104 weeks.⁵

23 Does it reduce alcohol cravings?

Early trials suggest effects on some drinking outcomes, but the answer depends on the outcome measured. Other studies include SEMALCO, which paired semaglutide with cognitive behavioral therapy, and a small oral trial, alongside the original 48-person study. The oral trial did not improve its primary craving outcome, though heavy-drinking outcomes favored treatment. This use remains investigational and is not an established replacement for alcohol-use-disorder care.^28,29,30

24 Does the alcohol research mean it helps people stop smoking?

No. A small randomized trial in daily smokers did not improve its primary laboratory smoking outcomes, though cigarette craving and body weight fell. It did not show smoking cessation.³¹