Wegovy Side Effects: Incidence Rates Across Clinical Trials

Where these incidence numbers come from

The most complete set of Wegovy side-effect rates is the adverse reactions table in the current Wegovy prescribing information. It pools three randomized, double-blind, placebo-controlled trials: 2,116 adults with obesity or overweight treated with 2.4 mg once weekly for up to 68 weeks and 1,261 treated with placebo, with a mean age of 48, 71% women, and 19% with type 2 diabetes [1].

The label cautions that because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the trials of one drug cannot be directly compared to rates in the trials of another drug and may not reflect the rates observed in clinical practice [1].

How common is each side effect at 2.4 mg?

In the label's pooled trials of Wegovy 2.4 mg, these reactions were reported at the following rates [1].

Any gastrointestinal reaction was reported by 73% of Wegovy-treated adults versus 47% on placebo, and severe gastrointestinal reactions by 4.1% versus 0.9% [1]. Dysesthesia here means altered skin sensation such as burning, tingling or pain from touch [1].

The label also lists reactions in the 1% to 4% range that appear more often on Wegovy than placebo, including gastritis (4% versus 1%) and injection site reactions (1.4% versus 1%), plus dysgeusia, an altered sense of taste, at 1.7% versus 0.5% [1].

Which side effects make people stop?

In the same pooled trials, 6.8% of adults on Wegovy 2.4 mg and 3.2% on placebo permanently stopped treatment because of an adverse reaction, most often nausea (1.8% versus 0.2%), vomiting (1.2% versus 0%) or diarrhea (0.7% versus 0.1%) [1]. In STEP 1 specifically, 4.5% of semaglutide-treated participants discontinued for a gastrointestinal event versus 0.8% on placebo [2].

At the higher dose the pattern holds: 5% of adults on 7.2 mg, 5% on 2.4 mg and 2% on placebo stopped for an adverse reaction, with gastrointestinal reasons accounting for 3%, 3% and 0.3% [1].

What changes at 7.2 mg?

The label now allows up to 7.2 mg weekly in adults who tolerate 2.4 mg for at least 4 weeks and need more weight loss; the pediatric maximum stays at 2.4 mg [1]. Two 72-week trials compared the doses directly in 1,311 adults on 7.2 mg, 304 on 2.4 mg and 303 on placebo [1]:

• Nausea: 39% on 7.2 mg, 35% on 2.4 mg, 13% on placebo
• Vomiting: 22%, 16%, 6%
• Dysesthesia: 22%, 6%, 0%
• Constipation: 20%, 19%, 8%
• Hair loss: 6%, 3%, 1% (8.4% of women versus 0.2% of men on 7.2 mg)
• Fatigue: 11%, 9%, 5%

The label states that dysesthesia increases with dose, and that 18% of people affected on 7.2 mg had not recovered by the end of the trial [1].

Tablets and ages 12 and older

Wegovy 25 mg daily tablets were approved for adults on 22 December 2025 [3]. In the one 64-week tablet trial (204 adults with obesity or overweight, no diabetes), the label says reaction types and frequencies were similar to the injection table, with severe gastrointestinal reactions in 2% versus 0% on placebo, dysesthesia in 5% versus 0%, and discontinuation for adverse reactions in 6.9% versus 5.9% (gastrointestinal reasons 3.4% versus 2%) [1].

In adolescents aged 12 and older on 2.4 mg for 68 weeks (133 versus 67), nausea occurred in 42% versus 18%, vomiting in 36% versus 10%, diarrhea in 22% versus 19%, headache in 17% versus 16% and abdominal pain in 15% versus 6% [1].

Gallbladder and pancreas

The label gives separate gallbladder figures rather than one combined rate. In adult weight-reduction trials, cholelithiasis (gallstones) was reported by 1.6% of Wegovy injection patients versus 0.7% on placebo, and cholecystitis by 0.6% versus 0.2%; with the tablets, cholelithiasis was 2.5% versus 1%. In the adolescent trial, cholelithiasis was 3.8% versus 0% and cholecystitis 0.8% versus 0% [1]. The label notes that substantial or rapid weight loss can increase gallstone risk, but that gallbladder disease was still more frequent on Wegovy than placebo after accounting for the degree of weight loss [1].

For pancreatitis, the label reports confirmed acute pancreatitis in 4 Wegovy-treated adults (0.2 per 100 patient-years) versus 1 on placebo, and average rises in amylase of 15% to 16% and lipase of 39%, of unknown significance in the absence of symptoms [1]. The label says to discontinue Wegovy if pancreatitis is suspected [1].

Heart rate, hair loss and skin sensation

The label's heart-rate warning reports a mean increase of 1 to 4 beats per minute and a rise of 20 bpm or more in 26% of Wegovy-treated patients versus 16% on placebo [1]. Hair loss appears at 3% versus 1% on 2.4 mg [1]. Postmarketing reports in the label include ileus, intestinal obstruction, severe constipation with fecal impaction, anaphylaxis, angioedema, acute kidney injury and alopecia, for which frequency cannot be estimated from voluntary reports [1].

What the cardiovascular trial adds

SELECT followed 17,604 adults with established cardiovascular disease and a BMI of 27 or more, without diabetes, for a mean of 39.8 months; the primary composite of cardiovascular death, non-fatal heart attack or non-fatal stroke occurred in 6.5% on semaglutide 2.4 mg versus 8.0% on placebo (hazard ratio 0.80, 95% CI 0.72 to 0.90), and 16.6% versus 8.2% permanently discontinued treatment, with a median exposure of 37.3 months on Wegovy and 38.6 months on placebo [4][1].

What FDA adverse event reports can and cannot show

FDA's adverse event database collects reports of suspected reactions; the agency states that a report does not establish that a drug caused the event and that the reports cannot be used to estimate how often an event occurs [5]. The numbers on this page come from the controlled trials and the label rather than from report tallies [1][5].