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Wegovy side effects and how to avoid them

From nausea to more serious risks, here’s everything you need to know about Wegovy side effects, and how to handle them.
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By | Updated on Feb. 11, 2025 Medically reviewed by Jesse P. Houghton, MD, FACG
Rx weight loss injection: Wegovy side effects

Key takeaways

  • Wegovy® is a GLP-1 receptor agonist weight loss medication that can help patients reduce their body mass index by managing their appetite and digestion.

  • The most common side effects of Wegovy are gastrointestinal in nature, including nausea, diarrhea, vomiting, and constipation.

  • The use of Wegovy may also cause serious side effects—like an increased risk of pancreatitis, gallbladder issues, hypoglycemia, and thyroid cancer—as well as some drug interactions.

  • Taking the prescribed doses, staying hydrated, eating small meals, and maintaining a healthy diet are all ways to potentially avoid Wegovy side effects.

  • Over-the-counter drugs and certain prescription medications may be viable treatments for certain side effects, but be sure to ask a healthcare professional first.

In this article:

Obesity affects around 40% of Americans, and right now, Wegovy (semaglutide) might just be the most popular treatment for it. Thousands of people are filling prescriptions for it every week, including a long list of celebrities. And that’s because, combined with diet and exercise, it can work wonders. As a GLP-1 receptor agonist, it mimics the appetite-regulating hormone glucagon-like peptide-1, reducing hunger, slowing digestion, and ultimately shedding pounds. 

However, it can affect the body in more than one way, which means it might also come with possible side effects. For anyone considering Wegovy, it’s important to know all the potential adverse reactions before starting treatment, plus how to avoid and manage them. Fortunately, we’ve got all that info right here. 

Common side effects of Wegovy

Wegovy’s clinical trials showed that the drug’s most common side effects are gastrointestinal. Nausea was the most common—44% of adults reported it, compared to 16% on a placebo—followed by diarrhea (30%), vomiting (24%), and constipation (24%). Other common side effects include: 

  • Abdominal pain
  • Headache
  • Fatigue
  • Indigestion
  • Dizziness
  • Abdominal distension
  • Eructation (burping)
  • Flatulence
  • Gastroesophageal reflux disease (GERD)
  • Gastritis
  • Stomach flu
  • Hair loss
  • Runny nose

Not everyone will experience the same side effects, and some people might not get any whatsoever. “Most of my patients have little to no side effects on these meds, and typically, the side effects are manageable,” says Dr. Supriya Rao, MD, gastroenterologist, managing partner at Integrated Gastroenterology Consultants. “For example, constipation, I can get them on something to help with the constipation, and it’s not a big deal.”

Serious side effects of Wegovy

The side effects listed above might be bothersome. They might even disrupt daily life. But they’re rarely dangerous. However, Wegovy does have some potential serious side effects that would require medical help. According to the drug’s prescribing information, they include:

  • Inflammation of your pancreas (pancreatitis)
  • Acute gallbladder disease and gallstones
  • Low blood sugar (hypoglycemia), especially in people with Type 2 diabetes
  • Kidney failure, acute kidney injury, and other kidney problems
  • Severe abdominal pain or stomach problems
  • Retinal disorders and changes in vision
  • Increased heart rate
  • Depression and suicidal thoughts
  • Severe allergic reactions
  • Increased risk of thyroid cancer

Wegovy, like the other GLP-1 agonists, all carry an FDA black box warning regarding an increased risk of medullary thyroid cancer. These medications should be avoided in people with a personal or close family history of thyroid cancer. Serious side effects are possible, but uncommon. A study in Obesity Reviews from 2024 found that semaglutide’s adverse effects were typically mild or moderate, not serious. A separate study in The American Journal of Cardiology had similar results, showing that mild gastrointestinal side effects are common, but serious ones that require discontinuation are rarer. 

That said, doctors still don’t take them lightly, especially reactions like pancreatitis. “If anybody has a history of pancreatitis, it’s pretty much a contraindication because the threshold for them getting pancreatitis again on this medication is pretty low,” Dr. Rao says. “Pancreatitis can range from being mild to needing hospitalization and being hospitalized for months.”

Dr. Rao also says she always gets baseline labs and consults patients on their family medical history of thyroid cancer before prescribing Wegovy. That’s because, in rare cases, it might cause an elevation of liver enzymes, and animal studies suggest that it might increase the risk of possible thyroid tumors. 

How soon do Wegovy side effects start?

Wegovy starts working in the body within 1–3 days, so side effects can start right away. “Oftentimes, I see it when we’re either starting the medication or increasing the dose. Usually, within the first couple of weeks, people are able to manage it, and it’s not a problem,” Dr. Rao says. “When you start increasing the dose, then it can manifest a little bit more.”

How long do Wegovy side effects last?

While Wegovy’s side effects may subside after you hit the maintenance dose of 1.7 or 2.4 mg, getting to that point might take some time. That’s because doctors often start patients at a low dose, then slowly titrate up to a maintenance dose over a few months. 

According to Dr. Diana Roman, PharmD, clinical pharmacist, and assistant professor at Marshall B. Ketchum University, “Wegovy is started at a low dose of 0.25 mg subcutaneously weekly and is gradually increased every 4 weeks, as tolerated, to a maximum dose of 2.4 mg weekly.” This dosage ramp-up (called titration) is designed to lower the chances of side effects—particularly common gastrointestinal ones like nausea—by letting the patient’s body get accustomed to the medication. However, each dosage increase might cause either recurring or temporary side effects. 

In some cases, Dr. Roman says doctors may choose to slow down the titration schedule if a patient is experiencing side effects. In cases when a patient cannot tolerate the gastrointestinal side effects of an increased dose of Wegovy, she says they may also revert back to the previous dose before trying the increase again later. 

What are the long-term side effects of Wegovy?

After successfully losing body weight, many people want to keep it off. The issue? Depending on the person, going off of Wegovy might bring back some of those unwanted pounds. In fact, a study from 2022 found that, on average, patients regained two-thirds of that weight after stopping Wegovy. Fortunately, other research has found that semaglutide is effective in maintaining weight loss over four years—the longest period of time that’s been studied. 

But while Wegovy’s benefits can persist, so can some long-term side effects. In that four-year study, 16.6% of patients discontinued treatment because of persistent adverse effects, compared to 8.2% in the placebo group. 

There isn’t a ton of research on the long-term side effects of semaglutide, but it has been linked to an increased risk of thyroid tumors. The FDA has even issued a black box warning for Ozempic, Wegovy, and all the GLP-1 agonists concerning this risk, although it’s still a fairly rare occurrence. Other potential long-term effects include an increased risk of pancreatitis (0.2 cases per 100 patient-years), gallbladder problems (1.6% compared to 0.7% on a placebo), acute kidney injury (0.4 cases per 100 patient-years), and hypotension (1.3% compared to 0.4% on a placebo).

Wegovy interactions

Side effects aren’t the only risks that Wegovy presents—like most other drugs, it can interact with other prescription and over-the-counter medicines. Wegovy’s known interactions include:

  • Insulin products: Like Wegovy, drugs like Lantus and Humalog lower blood sugar, which can lead to hypoglycemia when combined. 
  • Sulfonylureas or meglitinides: This group of drugs also helps control blood sugar levels, so like insulin, they can compound Wegovy’s hypoglycemic effects, presenting a risk of low blood sugar. 
  • ACE inhibitors: These cardiovascular drugs might also lower blood sugar. 
  • Other GLP-1 agonists: Drugs like Ozempic, Rybelsus, Victoza, and Trulicity have the same effects as Wegovy, so taking them at the same time is discouraged. 
  • Certain oral medications: Wegovy decreases gastric emptying, which can delay the absorption of other drugs. For drugs that have a thin line between safe and toxic doses—like warfarin, phenytoin, and levothyroxine—this can be a problem. 
  • Alcohol: It doesn’t directly interact with semaglutide, but alcohol can cause some of the same side effects, like nausea, dehydration, low blood sugar, blood pressure changes, and even an increased risk of acute pancreatitis. 
  • Garlic supplements: Garlic is totally fine as a seasoning in your favorite dishes. But in higher doses (like a supplement), it may lower blood sugar. 
  • Green tea: Green tea also lowers blood sugar, so drinking a lot of it also interact with Wegovy. 

This isn’t a comprehensive list of Wegovy’s possible interactions, and researchers are still studying certain ones, so it’s important to tell your healthcare provider about any prescription medication or supplements you’re taking before starting treatment. 

Safety measures while using Wegovy

Mild, common side effects might not stop a health care provider from prescribing Wegovy, or a patient from taking it. But there are some specific reasons that someone shouldn’t take it. People who should avoid it include:

  • Patients with a personal or family history of thyroid cancer: There’s some evidence that GLP-1s can increase the risk of a type of thyroid cancer called medullary thyroid carcinoma (MTC). A family history of MTC can make you more susceptible to getting it yourself, so it’s something you should discuss with your doctor. 
  • Patients with multiple endocrine neoplasia syndrome type 2 (MEN 2): This is a rare genetic disorder that can cause cancer in the thyroid or other glands. Considering Wegovy’s potential effect on the thyroid gland, people who have MEN 2 typically shouldn’t take it. 
  • Hypersensitivity or allergic reactions to semaglutide: Anyone who has ever had a serious allergic reaction to Ozempic, Wegovy, or other semaglutide medications shouldn’t take it. 
  • Children under 12 years old: Wegovy is only approved for people over the age of 12. 
  • Patients who are pregnant or planning on becoming pregnant: It’s unclear whether semaglutide can harm human fetuses, but animal studies have suggested that it might. 

Outside of the contraindications listed on the label, there are other people who should use Wegovy with caution, including:

  • Anyone with pre-existing gastrointestinal health issues: Because Wegovy can cause several gastrointestinal side effects, it might not be the best option for people with digestive problems, especially those with gastroparesis (delayed stomach emptying). 
  • People with a history of pancreatitis: This is another potential side effect of Wegovy, and people who have already had bouts of pancreatitis are more likely to get it again. 
  • People with a history of gallstones: Wegovy increases the risk of gallstones, so people who are predisposed to getting them might think twice before taking it. 
  • Diabetic patients who are taking other antidiabetic drugs: These drugs can lower your blood glucose, increasing the risk of hypoglycemia. 
  • Anyone with a history of depression or suicidal thoughts: Wegovy can affect moods, so these patients should be cautious as well. 
  • People who have diabetic retinopathy: This is an eye disease that can stem from diabetes, and Wegovy might make it worse. 

How to avoid Wegovy side effects

Sometimes, adverse effects are simply out of your control. Either they happen, or they don’t. But people taking Wegovy can also take certain measures to help reduce the potential risk. They include: 

    1. Stick to the schedule: Doctors increase Wegovy dosage gradually for a reason—the body needs time to adjust. So don’t take more than the prescribed dose, and always follow the doctor’s exact directions. 
    2. Stay hydrated: Not only might Wegovy cause dehydration (through vomiting or diarrhea), but dehydration can worsen other side effects, like headaches and constipation. 
    3. Eat a healthy, balanced diet: “If you’re having really huge, fatty meals, you’re not going to feel good on these meds because they’re working to make you stop eating that kind of food,” Dr. Rao says. She recommends a high-fiber, plant-forward diet instead. Lean proteins and avoidance of processed, sugary foods are best.
    4. Exercise regularly: Exercise isn’t just good for weight loss, but for digestion too. “ I always tell patients after you eat a meal to go for a walk afterwards because that really helps jump start digestion,” Dr. Rao says.
    5. Eat small meals: Dr. Roman encourages Wegovy patients to eat slowly and consume smaller portion sizes. Since Wegovy slows down digestion, small meals are easier to process, and larger meals might cause increased gastrointestinal discomfort. 
    6. Take Wegovy on the same day every week: This will help ensure that the drug’s levels stay consistent, reducing the risk of side effects. Any time of day is fine—with or without food—as long as it’s the same day every week. 
    7. Rotate the injection site: This can help avoid injection site irritation or reactions. 
    8. Track and report bodily changes: Patients who notice new feelings or potential side effects should tell a healthcare provider, since they might be able to help. 

How to treat side effects of Wegovy

The good news is that many of Wegovy’s common side effects are treatable. For example, anyone experiencing symptoms like nausea, diarrhea, constipation, or gas can most likely take over-the-counter medications to help. People who get headaches or other types of pain can usually take OTC pain medications. However, it’s important to run it by a doctor first. 

In some cases, however, the side effects may just subside on their own as the body adjusts to treatment. If they’re particularly severe or persistent, the doctor might also recommend lowering the dosage, switching to another medication, or stopping this type of medication entirely. 

Bottom line: Is Wegovy safe?

While it may present the risk of side effects, Wegovy is quite safe for most people. Even when side effects occur, they’re typically mild or moderate, and there are effective ways to avoid and treat them. However, Wegovy and other GLP-1 medications aren’t the best options for everyone. That’s why it’s crucial that potential patients speak with a doctor or healthcare provider beforehand to discuss their medical history, current medications, and other health conditions.