Sulfur burps on Wegovy (semaglutide 2.4 mg): Incidence, Severity, and Realistic Expectations

How often does the Wegovy label report belching?

The label's safety data come from three randomized, double-blind, placebo-controlled trials that included 2,116 adults with obesity or overweight treated with Wegovy 2.4 mg injection for up to 68 weeks and 1,261 treated with placebo [1]. In that pooled group, eructation was reported by 7% of people on Wegovy and under 1% on placebo [1].

Other upper-gut reactions in the same table, for context: dyspepsia 9% versus 3%, abdominal distension 7% versus 5%, flatulence 6% versus 4%, and gastroesophageal reflux disease 5% versus 3% [1]. Any gastrointestinal reaction was reported by 73% on Wegovy versus 47% on placebo [1].

Belching was not among the most common reasons for stopping treatment named in the Wegovy label [1]. In STEP 1, the 68-week trial of 1,961 adults without diabetes, 4.5% of participants on semaglutide stopped treatment because of gastrointestinal events versus 0.8% on placebo [2].

Are sulfur burps their own listed side effect?

Eructation is the label's term, and it is the entry that covers belching [1]. The 7% figure is for all belching, not specifically sulfur-smelling burps [1].

Semaglutide is a GLP-1 receptor agonist, and the label notes that it delays gastric emptying [1]. The label does not attach a mechanism to the belching itself.

How severe are they likely to be?

The adverse reaction table gives one percentage for eructation with no breakdown by severity [1]. What the label does track by severity is the broader group of severe gastrointestinal reactions, reported in 4.1% of people on Wegovy injection versus 0.9% on placebo [1]. The label's warning on severe gastrointestinal reactions says use has been associated with gastrointestinal adverse reactions, sometimes severe, and that Wegovy is not recommended in patients with severe gastroparesis [1].

In the pooled trials, 6.8% of adults on Wegovy 2.4 mg and 3.2% on placebo stopped because of an adverse reaction. The label names nausea (1.8% versus 0.2%), vomiting (1.2% versus 0%), and diarrhea (0.7% versus 0.1%) as the most common reasons; it does not give a stopping rate for belching [1].

When does it start, and how long does it last?

The label does not report when belching starts or how long it lasts [1]. Its dosing schedule raises the dose in four-week steps: 0.25 mg for weeks 1 to 4, 0.5 mg for weeks 5 to 8, 1 mg for weeks 9 to 12, 1.7 mg for weeks 13 to 16, then maintenance from week 17 at 2.4 mg (or 1.7 mg) [1]. The label reports eructation as a single rate across trials lasting up to 68 weeks rather than as a pattern that rises or falls with each dose level [1].

Semaglutide has an elimination half-life of about one week, and the label notes the drug stays in the body for roughly 5 to 7 weeks after the last 2.4 mg injection [1].

The 25 mg daily Wegovy tablet is covered by the same label. It says the reaction types and frequencies seen with the tablets were similar to the injection table, based on a 64-week trial of 204 adults with obesity or overweight and no diabetes [1].

What the label says to watch for

The Wegovy label attaches specific warnings to several gastrointestinal symptoms [1].

• Acute pancreatitis. The label describes persistent or severe abdominal pain, sometimes radiating to the back, which may or may not come with nausea or vomiting, and says to discontinue Wegovy if pancreatitis is suspected [1].
• Ileus, intestinal obstruction, and severe constipation with fecal impaction. These appear as postmarketing reports in the label, where frequency cannot be estimated from voluntary reports [1].
• Acute kidney injury from volume depletion. This occurred at 0.4 versus 0.2 cases per 100 patient-years, more often in people with prior kidney impairment and during dose titration, and often after gastrointestinal fluid loss [1].
• Severe gastroparesis. Wegovy is not recommended in patients with severe gastroparesis, per the label's severe gastrointestinal warning [1].