Ozempic side effects

What are the most common side effects of Ozempic?

According to the Turkish SmPC (KÜB), the most frequently reported side effects in clinical trials are nausea (very common), diarrhea (very common) and vomiting (common); they are generally mild or moderate in severity and short-lived. In type 2 diabetes trials with 0.5 mg and 1 mg semaglutide, nausea occurred in 17% and 19.9% of patients, diarrhea in 12.2% and 13.3%, and vomiting in 6.4% and 8.4%, respectively. These events led to discontinuation of treatment in 3.9% and 5% of patients and were reported most often in the first months of treatment. The SmPC also states that patients with low body weight may experience more digestive side effects. ^[1]

The frequency table in the SmPC is summarized below. ^[1] Frequency definitions: very common, more than 1 in 10 people; common, between 1 in 100 and 1 in 10; uncommon, between 1 in 1,000 and 1 in 100; rare, between 1 in 10,000 and 1 in 1,000; very rare, fewer than 1 in 10,000; not known, cannot be estimated from the available data.

At the weight management dose (2.4 mg), frequencies are higher

In the 68-week trials in the Turkish SmPC of Wegovy, nausea occurred in 43.9% of those taking semaglutide (placebo 16.1%), diarrhea in 29.7% (placebo 15.9%), vomiting in 24.5% (placebo 6.3%) and constipation in 24.2% (placebo 11.1%). Median durations were 8 days for nausea, 2 days for vomiting, 3 days for diarrhea and 47 days for constipation. Digestive events led to permanent discontinuation of treatment in 4.3% of patients and were reported most often during the dose-escalation period. ^[2]

What are the serious side effects and warnings?

• Thyroid C-cell tumors (US boxed warning): In mice and rats, semaglutide caused dose- and duration-dependent thyroid C-cell tumors with lifetime exposure. It is not known whether it causes such tumors, including medullary thyroid cancer, in humans. It is contraindicated in a personal or family history of medullary thyroid cancer or MEN 2; the US label states that the value of routine calcitonin or thyroid ultrasound monitoring for early detection is uncertain. ^[4] The Turkish SmPC also lists these two conditions as contraindications. ^[1]
• Acute pancreatitis: In the phase 3a trials, the frequency of confirmed acute pancreatitis was 0.3% with semaglutide and 0.2% with comparators; in the two-year cardiovascular trial it was 0.5% versus 0.6%. The SmPC states that the drug should be stopped if pancreatitis is suspected, not restarted if confirmed, and that caution is needed in a history of pancreatitis. ^[1]
• Gallstones and gallbladder inflammation: In weight management trials, cholelithiasis was reported in 1.6% of those taking semaglutide and led to cholecystitis in 0.6%; in placebo these rates were 1.1% and 0.3%. ^[2]
• Delayed gastric emptying and bowel obstruction: People with gastroparesis may experience more serious digestive side effects; it is not recommended in severe gastroparesis. ^[1] The post-marketing section of the US label includes ileus, bowel obstruction and severe constipation including fecal impaction. ^[4]
• Fluid loss and kidney: Nausea, vomiting and diarrhea can cause fluid loss and, in rare cases, impaired kidney function; the SmPC therefore asks for caution in people with kidney impairment. ^[1]
• Hypoglycemia: Severe hypoglycemia has not been seen with use alone; severe hypoglycemia was observed mainly with concomitant use of a sulfonylurea (1.2%) or insulin (1.5%). ^[1]
• Diabetic retinopathy: In the two-year trial of 3,297 people with type 2 diabetes at high cardiovascular risk, retinopathy complications occurred in 3% with semaglutide and 1.8% with placebo; the difference was observed in patients with known retinopathy who used insulin. ^[1]
• NAION: In June 2025, PRAC classified NAION as a “very rare” (at most 1 in 10,000 people) side effect of semaglutide. Large epidemiological studies show that the risk in people with type 2 diabetes is about doubled, corresponding to about one additional case per 10,000 person-years of treatment; clinical trial data also point to a slightly higher risk compared with placebo. If NAION is confirmed, treatment is stopped. ^[5]
• Severe allergic reactions: Anaphylaxis is listed as rare and angioedema as a side effect of unknown frequency. ^[1]

What is known before surgery and anesthesia?

According to the Turkish SmPC, cases of aspiration into the lungs have been reported in GLP-1 receptor agonist users undergoing general anesthesia or deep sedation; the risk of stomach contents due to delayed gastric emptying should be taken into account before the procedure. ^[1] The US label states that there are not enough data to make a recommendation on changing the fasting period or temporarily stopping the drug to reduce this risk. ^[4]

Guidelines take different approaches on this point. The multi-society guidance published in October 2024 (societies of anesthesiology, gastroenterology and obesity surgery) recommends that the drug may be continued before surgery in patients not at high risk of delayed gastric emptying; if a decision is made to stop the drug, that weekly drugs be stopped one week before surgery following the American Society of Anesthesiologists’ initial 2023 recommendation; and measures such as a liquid diet for at least 24 hours in at-risk patients. ^[7] This is a decision for the team planning the procedure.

Mental health: suicidal thoughts

PRAC completed the review it began in July 2023 in April 2024 and concluded that the available evidence does not support a causal relationship between GLP-1 receptor agonists (dulaglutide, exenatide, liraglutide, lixisenatide, semaglutide) and suicidal and self-harm thoughts and actions; it decided that no change to the product information was needed and that the matter would continue to be monitored. ^[6] The June 2025 public announcement of TEMD (Endocrinology and Metabolism Society of Türkiye), however, states that the drug may have the property of increasing depression and suicidal thoughts in some people. ^[9] The two assessments are documents of different kinds: one is a regulatory risk assessment, the other an information text from a professional society.

Does Ozempic cause hair loss?

According to the Turkish SmPC of Wegovy, in weight management trials hair loss was reported in 2.5% of those taking semaglutide and 1% of those taking placebo. Events were mostly mild and resolved in most patients while treatment continued. ^[2] The European product information lists hair loss among “common” side effects and states that it was reported more often in those who lost 20% or more of their weight. ^[3] Hair loss is not in the Turkish SmPC table for the diabetes doses of Ozempic; in the US Ozempic label, alopecia is among post-marketing reports, and a frequency cannot be calculated from these reports. ^{[1] [4]}

Does semaglutide cause muscle loss?

According to the European product information, in a 140-person subgroup of the STEP 1 trial, body composition was measured by DEXA. At 68 weeks, semaglutide was accompanied by a greater loss of fat mass than lean body mass and the body composition ratio improved compared with placebo; the reduction in total fat was accompanied by a reduction in visceral fat. The product information concludes from these results that most of the loss came from adipose tissue. ^[3]

This finding shows that lean mass also decreased; the DEXA result in the product information is not a measurement of muscle strength or physical function.

What is “Ozempic face” and is it due to the drug?

“Ozempic face” is a popular expression used for facial volume loss, skin sagging and more pronounced folds during weight loss; there is no such term in the side effect tables of the SmPC (KÜB) and the European product information. ^{[1] [3]}

A 2026 review examined 46 reports out of 958 records. In 20 patients followed with serial imaging, midface volume decreased by a median of 9%; by regression, about 7% midface volume loss was estimated for every 10 kg of weight loss. The author reports that similar changes are also seen after other routes of marked weight loss such as bariatric surgery, that the current evidence supports volume loss related to weight loss more than a drug-specific effect, that the independent effect of the rate of weight loss is uncertain, and that the evidence on aesthetic treatments is largely uncontrolled. ^[8] There is no randomized controlled trial on this topic; the data in the review consist of small series and surveys.

What is not known in the long term?

• Thyroid: The relevance of C-cell tumors in rodents for humans has not been determined. ^[4]
• Timing of NAION: According to the SmPC, there is no defined time interval for when NAION may develop after treatment starts. ^[1]
• Pregnancy: Data on use in pregnant women are limited; reproductive toxicity was seen in animal studies. ^[1]
• Antibodies: In weight management trials, antibodies against semaglutide were detected in 2.9–10.9% of those taking 2.4 mg; no neutralizing antibodies were seen. ^[2]

How do counterfeit products change the side effect risk?

The frequencies on this page belong to trials conducted with licensed products; they are not valid for products whose content and dose cannot be verified. In Türkiye, a letter from the Erzurum Provincial Health Directorate to the pharmacists’ chamber (chamber registration date May 20, 2026), referring to the TİTCK (Turkish Medicines and Medical Devices Agency) letter dated May 14, 2026, relays that reports of suspected counterfeiting of medicines containing GLP-1 receptor agonists have increased markedly; in pharmacy and pharmaceutical warehouse inspections, Ozempic, Saxenda and Wegovy pens and Mounjaro solution for injection are stated to carry a high counterfeit risk. The letter emphasizes that medicines should not be bought over the internet and that medicines that cannot be registered in the Medicine Track and Trace System (İTS) should not be kept or used. ^[10]

Limits of this page

This page summarizes side effects in product information and regulatory assessments; it does not assess whether a symptom is due to the drug and contains no recommendation on continuing treatment, changing the dose or stopping. According to the SmPC, health care professionals report suspected side effects to the Turkish Pharmacovigilance Center (TÜFAM). ^[1]