Wegovy is a once-weekly prescription drug prescribed to help people lose weight. It is becoming increasingly popular due to its effectiveness. 

However, Wegovy and other similar medications do have a number of side effects.  

If you have been prescribed Wegovy, you may wonder about the common side effects of taking the medication. As well as the severity of the less common side effects.

This article will give you an overview of Wegovy and summarize what you need to know about Wegovy’s side effects.

Image of a doctor explaining something to a patient

What is Wegovy?

Wegovy is the brand name for Novo Nordisk’s version of the drug semaglutide specially for weight loss. 

The Food and Drug Administration (FDA) approved Wegovy in June 2021 for people who are obese or who are overweight and have at least one weight-related condition. 

It has the same active ingredient as other drugs you may have heard of, like Ozempic

Wegovy helps people reduce the amount of food they eat by decreasing their appetite and by slowing down the digestive process. 

It helps you feel full for longer by delaying the emptying of food from your stomach into your small intestine.

It also stimulates the pancreas to release insulin and slow down your liver’s production of glucagon. These changes tend to decrease insulin resistance and lower overall blood sugar levels.

Wegovy comes in five different sizes of auto-injector pens with pre-measured doses ranging from 0.25 milligrams (mg) up to 2.4 mg. 

If you’re new to Wegovy, you’ll likely be prescribed a low dose, and your doctor will gradually increase it over time.

Injections of Wegovy are designed to be taken only once per week and should be taken on a consistent day of the week. 

What are the side effects of Wegovy?

Many people who take Wegovy will experience mild to moderate side effects and symptoms. 

The most common side effects are:

  • Nausea
  • Vomiting 
  • Diarrhea 
  • Stomach pain
  • Constipation 
  • Heartburn
  • Gas or bloat
  • Fatigue
  • Headache
  • Runny nose, sore throat, or congestion.

Nausea is the most common side effect that you should be prepared to experience—at least temporarily. 

Most of these symptoms are not serious, and many will fade over time as your body becomes acclimated to the medication. 

However, it is always a good idea to tell your doctor or medical provider about any side effects you experience. 

They can help with any symptoms that are bothering you. 

What are the more serious side effects of Wegovy?

There are also rare but more serious side effects and complications that you should be aware of:

  • Thyroid tumors, including cancer  
  • Pancreatitis 
  • Changes in vision 
  • Kidney problems 
  • Mental changes or depression
  • Serious allergic reactions
  • Hypoglycemia

Some people will also experience hypoglycemia (low blood sugar levels), especially if they take insulin at the same time. 

It’s important to be aware of the symptoms of low blood sugar and know how to act to correct it.

Low blood sugar can be dangerous if untreated, so be on the lookout for the following:

  • Dizziness or light-headedness 
  • Confusion 
  • Sudden changes in your mood or perception 
  • Shakiness 
  • A fast heartbeat
  • Any of the other symptoms of hypoglycemia

Your doctor should discuss all the potential side effects, from common to serious, and can answer the questions you have about the medication and its potential risks and benefits. 

If you believe you are having any of the serious side effects of Wegovy, it’s important to stop taking it and get medical attention right away. 

Do most people who take Wegovy experience side effects?

If you are experiencing side effects like nausea while taking Wegovy, you’re not alone. 

Some side effects, particularly gastrointestinal side effects, are very common. A large proportion of people who take Wegovy do experience at least some of the gastrointestinal side effects.

About 44% of people on a maximum dose experience nausea, while about 30% experience diarrhea, and about 25% experience vomiting. 

Around 10% of participants in clinical trials of the active ingredient in Wegovy (semaglutide) decided to stop taking the drug due to side effects like nausea.  

In total, 71.4% of clinical trial participants experienced some kind of side effects while taking semaglutide. 

How can I reduce the side effects of Wegovy?

Because a large proportion of people taking Wegovy will experience some of the common side effects of the medication, the drug manufacturer has published a helpful list of ways to reduce the common side effects. 

These recommendations include:

  • Temporarily change your diet to emphasize bland, low-fat foods like crackers, toast, or rice.
  • Eat foods that contain water. Novo Nordisk recommends foods like soups and gelatin.
  • Avoid lying down soon after eating a meal.
  • Get fresh air if you’re feeling like you have an upset stomach.
  • Eat more slowly.

People who’ve taken Wegovy and other similar medications also recommend breaking meals up into smaller snack-size portions and eating throughout the day—rather than consuming so many calories around mealtime.

Report any side effects you may be experiencing to your doctor and ask them for guidance as to how best to manage those symptoms. 

Your doctor or medical care team will be able to help make recommendations that take your health history and goals into account. 

This also may include temporarily decreasing your dose of Wegovy before bringing it back up again later. 

How long does it take for the side effects of Wegovy to stop?

The common side effects of Wegovy tend to ease within a few days to a week. 

Any symptoms lasting longer than a week should be reported to your doctor, even if you think they’re minor.

Part of the reason that your doctor will start you on a lower dose of Wegovy and work your way up over time is to help your body acclimate. 

This helps to prevent side effects like nausea from getting too bad.

If you’re finding the side effects of larger doses are too difficult to manage, your doctor may be able to temporarily reduce your weekly dose before trying the larger dose again later. 

This helps many people to become accustomed to the medication without all the side effects.

If you stop taking Wegovy altogether, most side effects stop within a week or two. The medication is almost totally eliminated from your body within about a month.

However, even though most people do experience some side effects like nausea, especially when first starting to use the medication, these symptoms generally tend to ease up over time. 

Does Wegovy cause mood swings?

Though shown to be rare in clinical trials, Wegovy and other semaglutide drugs can cause mood swings. 

According to the Mayo Clinic, Wegovy “may cause some people to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed.”

It’s not common, but if you experience any changes in your mood or mental state, it’s important to tell your doctor immediately.

Does anyone gain weight on Wegovy?

While people lose, on average, about 16% of their body weight after a year on Wegovy, that’s not to say that everyone loses weight. 

Trial data published in 2022 showed that just over 20% of people do not lose 5% or more of their body weight when taking semaglutide drugs like Wegovy. 

Anecdotal reports indicate that an even smaller percentage of people will continue gaining weight when on the drug. 

Though, it is sufficiently uncommon enough to not to be listed as an adverse effect in any of the clinical trials published to date.

However, weight loss after stopping treatment with Wegovy is very common.

Does Wegovy cause hair loss?

Wegovy itself does not cause hair loss, but 3% of people who participated in one clinical trial did experience hair loss while taking the drug.

It is hypothesized that hair loss was part of the body’s stress response to rapid weight loss. 

A small percentage of people who have weight loss surgeries will experience hair loss as a side effect.

Because both Wegovy and bariatric (weight loss) surgeries can cause rapid weight loss, hair loss can occur in a small number of cases.

Is Wegovy linked to thyroid tumors or cancer?

The FDA’s approval for Wegovy carries a warning about thyroid C-cell tumors.

For this reason, people with either a personal or family history of thyroid tumors, specifically medullary thyroid carcinoma (MTC) and patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) are not supposed to take Wegovy or other medications containing semaglutide.

As described by the FDA, the concern around thyroid tumors is based on the results of dosing similar medications in rodents. 

When dosed with a clinically relevant amount of the medication, some rats and mice developed thyroid tumors—including some which were cancerous. 

However, it’s not yet known if this risk applies to humans, as none of the human trial participants developed these tumors.

It’s important to know what the symptoms of thyroid tumors are and to discuss any relevant health history with your doctor and care team. 

What are the symptoms of taking too much Wegovy?

You should never take more Wegovy than you’re prescribed. 

Contact your doctor or a poison control center right away if you accidentally take too much Wegovy. 

An overdose of Wegovy or other semaglutide medication may cause severe nausea, persistent vomiting, and dangerously low blood sugar (hypoglycemia), among other symptoms.

Because Wegovy stays in your system for a long time, you may need to be monitored in a medical setting to ensure you’re staying hydrated and that your blood sugar levels are in a safe range.