Wegovy Side Effects: Tiredness, Hair Loss, Nausea and How Long They Last

The most common side effects of Wegovy are nausea, diarrhea, vomiting, constipation, stomach pain, headache, fatigue, indigestion, dizziness, bloating, burping, gas, stomach flu, acid reflux, altered skin sensation (dysesthesia) and hair loss, plus low blood sugar in people with type 2 diabetes.1

Source: Wegovy label, Table 3, three placebo-controlled trials in 2,116 adults on 2.4 mg for up to 68 weeks.1

Overall, 73% of adults on the Wegovy injection reported a gastrointestinal side effect, against 47% on placebo.1 In those trials, 6.8% stopped Wegovy because of side effects, against 3.2% on placebo; nausea, vomiting and diarrhea were the most common reasons.1

Yes. Fatigue, including weakness (asthenia), was reported by 11% of adults on Wegovy 2.4 mg, against 5% on placebo.1 On Wegovy HD 7.2 mg, it was 11%, against 9% on 2.4 mg and 5% on placebo in the same trials.1 The Medication Guide lists tiredness among the most common side effects.1

The label does not give a cause for fatigue. It does list conditions that can leave people tired or weak. Nausea, vomiting and diarrhea can cause fluid loss (dehydration), and the Medication Guide advises drinking fluids to lower that risk.1 In people with type 2 diabetes, especially those on insulin or a sulfonylurea, low blood sugar is a common side effect, and weakness and drowsiness are among its listed signs.1 Tiredness that does not improve is worth raising with your prescriber.

Yes, hair loss is a listed side effect of Wegovy: 3.3% of adults on 2.4 mg reported it, against 1% on placebo.1 The label links it to weight reduction.1

It was more common at the higher dose and in women:1

In the 7.2 mg trials, one hair loss case led to stopping treatment and five led to a dose reduction.1

Shedding after major weight loss usually recovers. The American Academy of Dermatology names losing 20 pounds or more as a trigger, says shedding usually shows up a few months later, and says hair tends to regain its normal fullness within six to nine months.3 The Wegovy label has no specific advice on preventing hair loss; for heavy or patchy shedding, a dermatologist can rule out other causes.3

For most people, Wegovy nausea is temporary and peaks during the dose increases: the label says gastrointestinal reactions were most frequently reported during dose escalation.1 A pooled analysis of the STEP 1 to 3 trials found that 98.1% of gastrointestinal events on Wegovy 2.4 mg were mild to moderate, and that they were transient and occurred mostly during or shortly after dose escalation.2

The label does not give a number of days. Semaglutide has a half-life of about 1 week.1 Nausea, vomiting or diarrhea that does not go away should be reported, because fluid loss can lead to kidney problems.1

Wegovy slows how fast the stomach empties.1 The label does not give a separate mechanism for nausea, but the slow 16-week dose escalation exists to reduce the risk of stomach side effects.1 Our Wegovy dosage guide explains that schedule.

Most Wegovy stomach side effects are transient: they cluster around dose increases and ease once the dose is stable.1,2 In the STEP 4 trial, people who stayed on the 2.4 mg maintenance dose after 20 weeks of escalation tolerated it well.2

If you stop Wegovy, semaglutide stays in the blood for about 5 to 7 weeks after the last 2.4 mg or 7.2 mg injection or 25 mg tablet.1

The label's main tool is pacing. If a dose is not tolerated during escalation, prescribers can delay the next increase by 4 weeks.1 The Medication Guide advises drinking fluids to reduce the chance of dehydration.1 Tell your prescriber about stomach problems that are severe or will not go away.1

The Wegovy pill (25 mg semaglutide tablets) has side effects of the same types and frequency as the Wegovy injection, according to its label.1 It was tested in a 64-week trial in 204 adults on the 25 mg tablet.1

• 6.9% stopped the Wegovy pill because of side effects, against 5.9% on placebo.1
• Gastrointestinal side effects caused 3.4% to stop, against 2% on placebo.1
• Severe gastrointestinal reactions were reported by 2%, against 0% on placebo.1
• Gallstones were reported by 2.5%, against 1% on placebo.1

The label does not report hair loss or fatigue rates separately for the pill. Like the injection, the pill is stepped up over time, starting at 1.5 mg daily for 30 days.1 Our guide to the Wegovy pill covers how it is taken.

Wegovy carries a boxed warning: semaglutide caused thyroid C-cell tumors in rodents, and it is unknown whether it causes them, including medullary thyroid carcinoma, in humans.1 Wegovy must not be used by people with a personal or family history of medullary thyroid carcinoma or with Multiple Endocrine Neoplasia syndrome type 2.1

The label's other serious warnings are:1

• Acute pancreatitis, including fatal cases with GLP-1 drugs.
• Gallbladder disease: gallstones in 1.6% on the injection against 0.7% on placebo.
• Low blood sugar, mainly with insulin or a sulfonylurea.
• Acute kidney injury from dehydration.
• Severe gastrointestinal reactions: 4.1% on the injection against 0.9% on placebo.
• Serious allergic reactions, including anaphylaxis and angioedema.
• Diabetic retinopathy complications in people with type 2 diabetes.
• Heart rate increase of 1 to 4 beats per minute on average.
• Pulmonary aspiration during anesthesia or deep sedation.
• Never share a Wegovy FlexTouch pen, even with a new needle.

On January 13, 2026, the FDA asked makers of GLP-1 weight-loss drugs, including Wegovy, to remove the warning about suicidal behavior and ideation from their labels.4 The current Wegovy label shows that section as removed in January 2026.1

At 7.2 mg, vomiting rose to 22% (16% on 2.4 mg) and altered skin sensation (dysesthesia) to 22% (6% on 2.4 mg).1 Of the people who had dysesthesia on 7.2 mg, 23% had a dose reduction.1 Discontinuation for side effects was 5% on both 7.2 mg and 2.4 mg.1

When do Wegovy side effects start? The label says gastrointestinal reactions were most frequently reported during dose escalation, the first 16 weeks of treatment.1

Do the side effects of Wegovy go away? For most people, the stomach side effects are transient and fade once the dose stops rising.2 Report any that are severe or persistent.1

Does the Wegovy pill make you tired? The label says side effects of the 25 mg tablet were similar in type and frequency to the injection, where fatigue affected 11%.1

Does Zepbound have fewer side effects than Wegovy? The two labels report different trials, and the Wegovy label notes that rates from different trials cannot be compared directly.1 See Wegovy vs Zepbound and our Zepbound side effects guide.

Is Wegovy safe in pregnancy? The label says Wegovy may cause fetal harm and should be stopped when pregnancy is recognized.1 See GLP-1s, pregnancy and breastfeeding.

Side effects and price both shape whether Wegovy is the right fit. Our Wegovy cost guide shows what the injection and pill cost, our cheapest Wegovy options compare where to get it, and Ozempic vs Wegovy explains how the two semaglutide brands differ. Our safety hub covers the warnings across GLP-1 drugs.

This article is for information only and is not medical advice. Report side effects to your prescriber, and seek urgent care for severe stomach pain, signs of an allergic reaction, or a lump in the neck. Wegovy is a prescription drug with real risks and side effects.