Wegovy side effects: how common they are, how long they last and which ones need a doctor
In Wegovy 2.4 mg weight trials, 44% of adults had nausea (vs 16% on placebo), 30% diarrhea, 24% vomiting and 24% constipation. Symptoms cluster around the 16-week dose escalation; in the STEP trials a nausea episode lasted a median of 8 days and most were mild to moderate. Serious risks include pancreatitis, gallbladder disease and a faster resting heart rate, so know the warning signs.
What are the most common Wegovy side effects?
Wegovy (semaglutide) is approved in the US to help adults with obesity, or with overweight plus a weight-related condition, lose weight and keep it off; for teens aged 12 and over with obesity; to lower the risk of heart attack and stroke in adults with heart disease and excess weight; and, as an injection, for a type of fatty liver disease with scarring (MASH). It comes as a weekly injection and also as a 25 mg once-daily tablet.
The core safety data come from three placebo-controlled trials in which 2,116 adults took 2.4 mg for up to 68 weeks. Their average age was 48 and 71% were women, so these numbers describe people treated for weight, not diabetes alone.
| Side effect | Placebo | Wegovy 2.4 mg |
|---|---|---|
| Nausea | 16% | 44% |
| Diarrhea | 16% | 30% |
| Vomiting | 6% | 24% |
| Constipation | 11% | 24% |
| Abdominal pain | 10% | 20% |
| Headache | 10% | 14% |
| Fatigue | 5% | 11% |
| Indigestion | 3% | 9% |
| Dizziness | 4% | 8% |
| Burping | under 1% | 7% |
| Hair loss | 1% | 3% |
Bloating, gas, reflux and gastritis were also more common than on placebo. In people with type 2 diabetes, low blood sugar (below 54 mg/dL) occurred in 6.2% vs 2.5%.
Other doses and forms. The 7.2 mg dose, an option for adults who tolerate 2.4 mg, brought slightly more nausea (39% vs 35% on 2.4 mg) and vomiting (22% vs 16%), plus a jump in altered skin sensations such as tingling, burning or skin sensitivity (22% vs 6%). The 25 mg tablet showed a pattern similar to the injection. In the teen trial, vomiting was more frequent than in adults (36% vs 10% on placebo).
When do Wegovy side effects start, and how long do they last?
Wegovy climbs slowly so your gut can adapt: 0.25 mg in weeks 1–4, 0.5 mg in weeks 5–8, 1 mg in weeks 9–12, 1.7 mg in weeks 13–16, and the maintenance dose (usually 2.4 mg) from week 17. If a step isn’t tolerated, the label lets your prescriber delay the next increase by 4 weeks. Our dose escalation guide walks through each step.
The STEP data show the typical arc:
- Onset: most first digestive symptoms appeared during escalation and leveled off after week 20.
- Peak: nausea, diarrhea and vomiting were most common around week 20, then declined; nausea fell the most.
- Length: a median single episode lasted 8 days for nausea, 3 days for diarrhea and 2 days for vomiting. Constipation lasted longer (median 47 days vs 35 on placebo).
- Adjustments: 12.5% had a dose reduced or paused for digestive symptoms, and most of them finished the trial still on treatment.
Feeling sick isn’t a sign the medicine works better. In STEP 1, average weight change was −14.9% vs −2.4% on placebo, and the pooled analysis found similar weight loss with or without digestive side effects.
What are the serious side effects of Wegovy?
Boxed warning: thyroid C-cell tumors
Semaglutide caused thyroid C-cell tumors in rodents; it’s unknown whether it does in people. Don’t use Wegovy if you or a family member have had medullary thyroid carcinoma or if you have MEN 2, and report a neck lump, trouble swallowing or persistent hoarseness.
Gallbladder disease
Gallstones affected 1.6% of adults on the injection vs 0.7% on placebo, and gallbladder inflammation 0.6% vs 0.2%. In the teen trial gallstones reached 3.8% vs 0%. The label notes the excess remained after accounting for weight loss. Signs: upper stomach pain, fever, yellow skin or eyes, pale stools.
Pancreatitis
Confirmed cases were rare (0.2 per 100 patient-years vs under 0.1 on placebo), but serious. Severe belly pain that won’t go away, sometimes reaching your back, means stopping Wegovy and calling your provider right away.
Faster heart rate, low blood pressure and fainting
Wegovy carries a heart-rate warning. Resting heart rate rose by 1 to 4 beats per minute on average, but at some visit 26% of adults had a rise of 20 or more (vs 16% on placebo). Low blood pressure (1.3% vs 0.4%) and fainting (0.8% vs 0.2%) were also more common, partly linked to fluid loss and more frequent in people on blood-pressure medicines. Tell your provider if your heart races at rest for several minutes.
Kidneys, low blood sugar and eyes
Acute kidney injury occurred at 0.4 vs 0.2 cases per 100 patient-years, often with vomiting, diarrhea or dehydration, and more often during dose increases. Low blood sugar is more likely if you also use insulin or a sulfonylurea. In people with type 2 diabetes, diabetic retinopathy was reported in 4% vs 2.7%.
Other label warnings
Severe digestive reactions (4.1% vs 0.9%), serious allergic reactions, and rare reports of food entering the lungs during anesthesia or deep sedation are also listed, so tell every care team you take Wegovy before a procedure. In the SELECT heart trial, hip and pelvic fractures were more common on Wegovy in women (1% vs 0.2%) and in people aged 75 and over (2.4% vs 0.6%).
What about mood and suicidal thoughts?
The suicidal behavior and ideation warning was removed from the label in February 2026, after an FDA review of 91 trials with 107,910 patients found no increased risk. The FDA still advises reporting new or worsening depression or suicidal thoughts; in the US, call or text 988 in a crisis.
What helps with Wegovy side effects?
Our deep dives cover the practical steps:
- Nausea and vomiting: small, low-fat meals, eating slowly, sipping fluids between meals. See GLP-1 nausea relief.
- Constipation: fluids, gradual fiber and daily movement; ask a pharmacist before laxatives. Read the constipation guide.
- Low appetite: protein-first small plates help protect muscle. See what to eat on a GLP-1.
- Hair shedding: linked to weight reduction in the label and usually temporary; our hair loss guide explains what helps.
- Drinking: alcohol can worsen nausea and dehydration. Read alcohol and GLP-1 medicines.
When should you call your doctor about Wegovy side effects?
Seek urgent care for severe stomach pain that won’t go away; vomiting or diarrhea that stops you keeping fluids down, or very little urine; swelling of the face, lips or throat or trouble breathing; upper stomach pain with fever or yellowing; fainting; or a racing heart at rest that doesn’t settle.
Book a regular appointment if side effects last weeks at a stable dose, you notice vision changes or a neck lump, you’re planning surgery, or you’re planning a pregnancy: the label advises stopping Wegovy at least 2 months beforehand.
What should you log on Wegovy?
During escalation, a few notes make a big difference at appointments:
- Dose step and date, so flares can be matched to increases
- Each symptom with a severity rating and how many days it lasted
- Fluids, meals and bowel movements on rough days
- Dizziness, fainting or racing-heart episodes
- Weight and waist trend, alongside strength and energy
GLPMate’s Wegovy tracker logs doses with reminders and injection sites, and the side-effect log records severity next to each dose step; the doctor report turns it into a PDF. This article is educational only and not medical advice. Talk to your doctor about any side effect that worries you.
FAQ
What are the most common side effects of Wegovy?
Digestive ones. In the label's 2.4 mg weight trials, nausea affected 44% of adults vs 16% on placebo, diarrhea 30% vs 16%, vomiting 24% vs 6% and constipation 24% vs 11%. Headache, fatigue, indigestion, dizziness, bloating, burping and hair loss were also more common than on placebo.
How long do Wegovy side effects last?
Most appear during the 16-week dose escalation. In the pooled STEP trials, nausea, diarrhea and vomiting peaked around week 20 and then declined, with a median episode of 8, 3 and 2 days respectively; constipation lasted longer, with a median of 47 days. Tell your prescriber if symptoms persist at a stable dose.
Are side effects worse on Wegovy 7.2 mg?
Somewhat. In 72-week trials, nausea affected 39% on 7.2 mg vs 35% on 2.4 mg, vomiting 22% vs 16%, and altered skin sensations such as tingling or burning 22% vs 6%. Among people with those skin symptoms on 7.2 mg, 23% had a dose reduction. The higher dose is only for adults who tolerated 2.4 mg.
Does Wegovy still carry a suicidal thoughts warning?
No. In January 2026 the FDA asked for the warning to be removed after a review of 91 trials with more than 100,000 patients found no increased risk, and the current label lists it as removed. The FDA still advises telling a doctor about new or worsening depression or suicidal thoughts; in the US, call or text 988 in a crisis.
Sources
- WEGOVY (semaglutide) injection and tablets, US Prescribing Information and Medication Guide, Novo Nordisk — revised 06/2026 (DailyMed) — indications; 0.25 → 0.5 → 1 → 1.7 → 2.4 mg escalation, optional 7.2 mg, 25 mg tablets, 4-week delay option; Table 3 (2.4 mg vs placebo) and Table 4 (7.2 mg); GI 73% vs 47%, severe GI 4.1% vs 0.9%; discontinuation 6.8% vs 3.2%; dysesthesia; teen data; boxed warning and warnings on pancreatitis, gallbladder, hypoglycemia, kidney injury, heart rate, retinopathy, allergy, anesthesia; hypotension, syncope, fractures; suicidal behavior and ideation warning listed as removed 02/2026
- Wilding et al., NEJM 2021 (STEP 1) — semaglutide 2.4 mg vs placebo, 68 weeks, 1,961 adults without diabetes — mean weight change −14.9% vs −2.4%; nausea and diarrhea most common, typically transient and mild to moderate; 4.5% vs 0.8% stopped for GI events
- Wharton et al., Diabetes Obes Metab 2022 — GI tolerability of semaglutide 2.4 mg (pooled STEP 1–3 and STEP 4) — 98.1% of GI events mild to moderate; nausea, diarrhea and vomiting peaked around week 20; median episode 8, 3 and 2 days; constipation median 47 days; 12.5% had a dose reduction or pause; 4.3% stopped; weight loss similar with or without GI events
- US FDA Drug Safety Communication, 13 January 2026 — removal of the suicidal behavior and ideation warning from GLP-1 RA labels (Saxenda, Wegovy, Zepbound) — meta-analysis of 91 trials with 107,910 patients and a large claims cohort found no increased risk; patients should still report new or worsening depression or suicidal thoughts
Sources checked:
This article is educational and is not medical advice, diagnosis or treatment. Medication decisions — including dose changes and what to do after a missed dose — belong with your prescriber. If you experience severe symptoms, seek medical care.