Semaglutide side effects: trial rates by dose

Side-effect rates for semaglutide come from the adverse-reaction tables in the FDA labels. Each table compares a dose with placebo in specific trials, so the placebo column matters as much as the drug column. The figures below are copied from the Wegovy label (revised 6/2026) and the Ozempic label on DailyMed.

Wegovy 2.4 mg side effects vs placebo

Label Table 3 pools three weight-management trials of up to 68 weeks: 2,116 adults on Wegovy 2.4 mg and 1,261 on placebo. It lists reactions seen in at least 2% of Wegovy users and more often than with placebo. (Novo Nordisk, Jun 18, 2026)

The difference column is simple subtraction. It shows that diarrhea, which looks common at 30%, was also reported by 16% of people on placebo; vomiting has the larger gap. “Abdominal pain” is a grouped term that includes upper and lower abdominal pain, gastrointestinal pain, tenderness and discomfort. “Fatigue” includes asthenia.

Permanent discontinuation because of adverse reactions occurred in 6.8% of people on 2.4 mg and 3.2% on placebo. (Novo Nordisk, Jun 18, 2026) In the separate SELECT cardiovascular trial, adverse events led to permanent discontinuation in 16.6% on semaglutide vs 8.2% on placebo over a mean follow-up of 39.8 months. (New England Journal of Medicine, Dec 14, 2023)

Wegovy 7.2 mg (Wegovy HD) side effects

Wegovy HD was approved on March 19, 2026. Label Table 4 draws on two 72-week trials (Studies 8 and 9): 1,311 adults on 7.2 mg, 304 on 2.4 mg and 303 on placebo. It lists reactions reported in at least 2% of people on 7.2 mg and more often than with 2.4 mg and placebo. (Novo Nordisk, Jun 18, 2026)

Dysesthesia is the standout. The label defines it to include paresthesia, hyperesthesia, burning sensation, allodynia, skin burning sensation, skin pain and sensitive skin. It rose from 6% at 2.4 mg to 22% at 7.2 mg in these trials. Note that the 2.4 mg arm here reported 6%, while the pooled Table 3 trials reported 2%. Different trials, populations and durations produce different rates, so compare columns within one table, not across tables.

Ozempic 0.5 mg and 1 mg side effects

The Ozempic label’s Table 1 comes from two placebo-controlled trials in adults with type 2 diabetes: 260 on 0.5 mg, 261 on 1 mg and 262 on placebo. It lists reactions reported in at least 5% of Ozempic users. (Novo Nordisk, Jun 1, 2026)

Nausea and vomiting both rose with dose: nausea from 15.8% to 20.3%, and vomiting from 5% to 9.2%. The label’s most common reactions (5% or more) are nausea, vomiting, diarrhea, abdominal pain and constipation.

What the Ozempic table does not include

Readers often look for Ozempic rates of headache, fatigue or hair loss. The label does not give them:

• Headache appears only in the postmarketing section (6.2), with no incidence.
• Alopecia (hair loss) appears only in the postmarketing section, with no incidence.
• Fatigue is listed among “other adverse reactions with a frequency of >0.4%”, with no arm-specific rate.

(Novo Nordisk, Jun 1, 2026)

Any page that quotes an Ozempic hair-loss or headache percentage is not quoting the label. The Ozempic trials also used lower doses (0.5 and 1 mg) in people with type 2 diabetes, so their rates cannot be lined up against Wegovy’s 2.4 mg weight-management rates.

Boxed warning: risk of thyroid C-cell tumors

Both labels open with the same boxed warning: “WARNING: RISK OF THYROID C-CELL TUMORS.” In rodents, semaglutide caused dose-dependent and treatment-duration-dependent thyroid C-cell tumors at clinically relevant exposures. The Ozempic label states that it is unknown whether the drug causes these tumors, including medullary thyroid carcinoma (MTC), in humans, because the human relevance of the rodent finding has not been determined. Both products are contraindicated in people with a personal or family history of MTC or with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). (Novo Nordisk, Jun 18, 2026) (Novo Nordisk, Jun 1, 2026)

The Ozempic boxed warning also tells prescribers to counsel patients about thyroid tumor symptoms, such as a mass in the neck, trouble swallowing, shortness of breath or persistent hoarseness, and says routine calcitonin or thyroid ultrasound monitoring is of uncertain value for early detection. (Novo Nordisk, Jun 1, 2026)

February 2026 label change: suicidal behavior warning removed

The current Wegovy label lists “Suicidal Behavior and Ideation (5.10)” as “(Removed) 02/2026” under Recent Major Changes, and the Warnings and Precautions section no longer contains that entry. (Novo Nordisk, Jun 18, 2026)

Older documents still mention the warning. The FDA’s March 8, 2024 announcement of Wegovy’s cardiovascular indication referred to it because it was part of the label then. (FDA, Mar 8, 2024) When a source and the label disagree, the label’s revision date tells you which is current. Any change in mood or behavior should still be raised with a prescriber.

How to read these numbers

(Novo Nordisk, Jun 18, 2026) (Novo Nordisk, Jun 1, 2026)

A few rules keep comparisons honest. Subtract the placebo rate to see the drug’s added effect. Compare doses only within the same table, because trials differ in population, duration and dose.

The label ladders raise the dose in 4-week steps, and the Wegovy label allows a 4-week delay when a step is not tolerated; see the semaglutide dosage chart and the titration calculator. The semaglutide plotter shows how the modeled amount builds with each step. Approval history is on the semaglutide hub. For any symptom, talk to your prescriber.