What are the most common side effects of semaglutide?

Common side effects in the Wegovy injection trials

The Wegovy label's side-effect table comes from three randomized, double-blind, placebo-controlled trials in adults with obesity or overweight: 2,116 adults took Wegovy 2.4 mg injection for up to 68 weeks and 1,261 took placebo, and 19% of participants had type 2 diabetes at baseline. [1]

The label notes: "Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice."

The Wegovy label says stomach and bowel side effects were most frequently reported while the dose was being increased.

Adverse reactions reported in 2% or more of adults taking Wegovy 2.4 mg injection, and more often than with placebo, in three weight-reduction trials. Source: Wegovy prescribing information, Revised 06/2026, Section 6.1, Table 3.

The low blood sugar row comes from one trial in adults with type 2 diabetes who were not taking insulin (403 on Wegovy, 402 on placebo), and low blood sugar was defined as blood glucose below 54 mg/dL, with or without symptoms.

In the table, abdominal pain includes upper and lower abdominal pain, gastrointestinal pain, abdominal tenderness, abdominal discomfort and epigastric discomfort, and fatigue includes asthenia.

In the Wegovy label's weight-reduction trials in adults, 73% of people on Wegovy injection and 47% on placebo reported stomach and bowel side effects, including severe reactions in 4.1% of people on Wegovy injection and 0.9% on placebo.

In the Wegovy 2.4 mg injection trials, 6.8% of people on Wegovy and 3.2% on placebo stopped treatment permanently because of side effects. Stomach and bowel side effects specifically caused 4.3% of adults on Wegovy injection to stop treatment permanently, versus 0.7% on placebo. The most common side effects leading to stopping were nausea (1.8% on Wegovy vs 0.2% on placebo), vomiting (1.2% vs 0%) and diarrhea (0.7% vs 0.1%).

Sources: Wegovy injection prescribing information, Revised 06/2026.

Side-effect percentages from the Wegovy trials describe Wegovy only and are not Ozempic percentages. Ozempic injection, Ozempic tablets and Rybelsus tablets are separate semaglutide products, each with its own FDA prescribing information, and this page does not apply Wegovy's numbers to them.

The Ozempic injection label lists nausea, vomiting, diarrhea, abdominal pain and constipation as its most common side effects, each reported by at least 5% of patients. [2] The Rybelsus and Ozempic tablet label lists nausea, abdominal pain, diarrhea, decreased appetite, vomiting and constipation as its most common side effects, each reported by at least 5% of patients. [3]

Sources: Wegovy injection prescribing information, Revised 06/2026; Wegovy tablets prescribing information, Revised 06/2026; Ozempic injection prescribing information, Revised 05/2026; Ozempic tablets prescribing information, Revised 1/2026; Rybelsus tablets prescribing information, Revised 1/2026.

Wegovy tablets share one FDA prescribing information document with Wegovy injection, but the side-effect table on this page comes from the injection trials only. In the Wegovy 25 mg tablet trial, the types and frequency of common side effects were similar to those in the Wegovy injection trials, according to the Wegovy label. In the Wegovy 25 mg tablet trial, 6.9% of people on Wegovy tablets and 5.9% on placebo stopped treatment because of side effects.

Sources: Wegovy tablets prescribing information, Revised 06/2026.

Boxed warning: thyroid C-cell tumors

Wegovy injection, Wegovy tablets, Ozempic injection, Ozempic tablets and Rybelsus tablets all carry a boxed warning about thyroid C-cell tumors in their prescribing information.

The Wegovy prescribing information's boxed warning says: "In rodents, semaglutide causes dose-dependent and treatment-duration-dependent thyroid C-cell tumors at clinically relevant exposures. It is unknown whether WEGOVY causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans as human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined."

A finding in rodents is not a human diagnosis, and unknown in humans is not the same as no risk.

The Wegovy label, the Ozempic injection label, and the Rybelsus and Ozempic tablet label each say that people with a personal or family history of medullary thyroid carcinoma (MTC), or who have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2), should not use semaglutide.

The Wegovy Medication Guide says to tell your healthcare provider if you get a lump or swelling in your neck, hoarseness, trouble swallowing, or shortness of breath.

Sources: Wegovy injection prescribing information, Revised 06/2026; Wegovy tablets prescribing information, Revised 06/2026; Ozempic injection prescribing information, Revised 05/2026; Ozempic tablets prescribing information, Revised 1/2026; Rybelsus tablets prescribing information, Revised 1/2026.

Other serious risks

The Wegovy prescribing information, which covers both Wegovy injection and Wegovy tablets, also warns about acute pancreatitis, gallbladder disease, low blood sugar (with a higher risk when taken with insulin or a sulfonylurea), kidney injury from dehydration, severe stomach and bowel reactions, serious allergic reactions, diabetic eye complications in people with type 2 diabetes, a faster heart rate, and inhaling stomach contents during anesthesia or deep sedation.

In Wegovy trials in adults for weight reduction, gallstones were reported by 1.6% of people on Wegovy injection and 0.7% of people on placebo.

The Wegovy label says that using Wegovy with insulin or with an insulin secretagogue such as a sulfonylurea may increase the risk of low blood sugar, including severe low blood sugar.

The Wegovy Medication Guide says that Wegovy may increase the chance of food getting into the lungs during surgery or other procedures that use anesthesia or deep sedation, and to tell all your healthcare providers that you are taking Wegovy before you are scheduled to have surgery or other procedures.

In weight-reduction trials, resting heart rate rose by 1 to 4 beats per minute on average with Wegovy injection compared with placebo.

In the SELECT trial, which was funded by semaglutide's manufacturer and enrolled adults aged 45 or older with established cardiovascular disease and overweight or obesity, without diabetes, 16.6% of people taking semaglutide 2.4 mg stopped treatment permanently because of an adverse event, compared with 8.2% on placebo, over a mean follow-up of about 3.3 years [4].

Sources: Wegovy injection prescribing information, Revised 06/2026; Wegovy tablets prescribing information, Revised 06/2026; Ozempic injection prescribing information, Revised 05/2026; Ozempic tablets prescribing information, Revised 1/2026; Rybelsus tablets prescribing information, Revised 1/2026.

What regulators have said about vision and mood

The European Medicines Agency's safety committee concluded in June 2025 that the eye condition NAION is a very rare side effect of semaglutide, meaning it may affect up to 1 in 10,000 people taking it. The conclusion rests on several large epidemiological studies in adults with type 2 diabetes, which suggest about one additional case of NAION per 10,000 person-years of treatment. [5]

This is an EU regulator's conclusion from observational data, so it is treated as emerging evidence, and it covers semaglutide only. The agency advises anyone with sudden vision loss or rapidly worsening eyesight during treatment to contact a doctor without delay.

In January 2026, FDA requested removal of suicidal behavior and ideation warning language from the labels of Wegovy, Saxenda and Zepbound. FDA reviewed 91 placebo-controlled trials with 107,910 patients and a retrospective claims-data study of 2,243,138 people with type 2 diabetes who started a GLP-1 medicine or an SGLT2 inhibitor, and the results did not show an increased risk of suicidal thoughts or behavior or of other relevant psychiatric adverse events such as anxiety, depression, irritability or psychosis. [6]

FDA advises patients to continue taking their medication as prescribed and to tell their health care professional about "new or worsening depression, suicidal thoughts, or any unusual changes in mood or behavior".

Compounded semaglutide: not studied in these trials

Compounded semaglutide is a different product from Wegovy, Ozempic and Rybelsus.

The rates in this page's table come only from trials of Wegovy injection, so this page has no comparable rate table for compounded semaglutide. In searches of PubMed, Europe PMC and ClinicalTrials.gov on October 1, 2026, we found no published randomized trial of a compounded semaglutide product. ClinicalTrials.gov lists a registered randomized trial that uses semaglutide prepared in a compounding base (NCT07092605); it had not reported results as of October 1, 2026. [7]

On its page 'FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss' (FDA page content current as of October 1, 2026), FDA says that, as of May 31, 2026, it had received '990 reports of adverse events associated with compounded semaglutide.' FDA adds: 'It is not always possible to determine if the adverse event directly resulted from use of the drug or if other factors may have contributed to these adverse events.' FDA also says that federal law does not require state-licensed pharmacies that are not outsourcing facilities to submit adverse events to FDA, 'so it is likely that adverse events from compounded versions of these drugs are underreported.' FDA further says: 'Many of the adverse events reported for compounded products appear to be consistent with adverse events related to the FDA-approved versions of these products.'

On its page 'FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss' (FDA page content current as of October 1, 2026), FDA says: 'FDA received multiple reports of adverse events, some requiring hospitalization, that may be related to dosing errors associated with compounded injectable semaglutide products.' FDA also says: 'Additionally, the agency has received adverse event reports that may be related to patients prescribed compounded semaglutide or tirzepatide products in doses beyond what is in the FDA-approved drug label.'

Compounded semaglutide is not FDA-approved. FDA states: 'Compounded drugs are not FDA-approved. This means that FDA does not verify the safety, effectiveness or quality of compounded drugs before they are marketed.' FDA determined that the shortage of semaglutide injection products was resolved on February 21, 2025, and said on April 1, 2026 that semaglutide was not on its drug shortage list.

Regulatory status checked September 27, 2026. Sources: www.accessdata.fda.gov/…/209637s038lbl.pdf; www.accessdata.fda.gov/…/213051Orig1s030lbl.pdf; www.accessdata.fda.gov/…/215256s025lbl.pdf; www.fda.gov/…/fda-clarifies-policies-compounders-national-glp-1-supply-begins-stabilize; public-inspection.federalregister.gov/…/2026-12937.pdf; www.fda.gov/…/fda-proposes-exclude-semaglutide-tirzepatide-and-liraglutide-503b-bulks-list; www.fda.gov/…/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss; www.fda.gov/…/compounding-and-fda-questions-and-answers; www.accessdata.fda.gov/…/218316Orig1s000ltr.pdf; www.accessdata.fda.gov/…/218316s007lbl.pdf

Who should avoid semaglutide

The Wegovy label, the Ozempic injection label, and the Rybelsus and Ozempic tablet label each list a personal or family history of medullary thyroid carcinoma (MTC), or MEN 2, or a prior serious allergic reaction to semaglutide or its ingredients, as a reason not to use semaglutide.

The Wegovy label advises stopping Wegovy at least 2 months before a planned pregnancy because semaglutide stays in the body for a long time.

A licensed clinician reviews your health history, including thyroid history, pancreatitis, gallbladder disease, pregnancy plans and other medicines.

Whether semaglutide is appropriate for a specific person, including with other conditions or medicines, is a decision for a licensed clinician who reviews a full medical history.

Sources: Wegovy injection prescribing information, Revised 06/2026; Wegovy tablets prescribing information, Revised 06/2026; Ozempic injection prescribing information, Revised 05/2026; Ozempic tablets prescribing information, Revised 1/2026; Rybelsus tablets prescribing information, Revised 1/2026.

Does this apply to other GLP-1 medicines?

Semaglutide is a GLP-1 receptor agonist: according to the Wegovy prescribing information, it selectively binds to and activates the GLP-1 receptor, the target for the natural hormone GLP-1.

The rates in this page's table come from Wegovy 2.4 mg injection trials only, so they do not describe other semaglutide products or other medicines in the same class.

Tirzepatide is a separate medicine with its own FDA prescribing information and its own reported side-effect rates, which this page does not report.

Semaglutide vs tirzepatide comparison →

What to do if you notice a side effect

Tell your prescriber about any side effect, especially one that is severe or does not improve.

The Wegovy Medication Guide says to talk to your healthcare provider about any side effect that bothers you or does not go away.

The Wegovy Medication Guide says to stop using Wegovy and get medical help right away if you have any symptoms of a serious allergic reaction, including swelling of your face, lips, tongue or throat, or problems breathing or swallowing.

The Wegovy Medication Guide says to stop using Wegovy and call your healthcare provider right away if you have severe pain in your stomach area that will not go away, with or without nausea or vomiting, which may be a sign of pancreatitis.

If you have severe symptoms, call 911 or seek emergency care. Report side effects to FDA MedWatch.

Connect with a licensed provider

A licensed clinician reviews your health history to decide whether semaglutide is appropriate for you and, if it is prescribed, how to monitor you for side effects.

Completing an intake form or making a payment does not guarantee a prescription.

Compounded semaglutide is not FDA-approved. See FDA's statement.

Connect With a Licensed Provider

A licensed clinician decides whether treatment is appropriate. A prescription is not guaranteed.

Related diagnostics and treatments

• Semaglutide for weight loss (overview) →
• Is semaglutide FDA-approved for weight loss? →
• Semaglutide vs tirzepatide comparison →