Semaglutide injection side effects and how to manage them

Semaglutide is a FDA-approved medication that controls blood sugar levels in people with type 2 diabetes, reduces the risk of heart attack and stroke in people with type 2 diabetes and heart disease, and promotes weight loss in people with overweight and obesity. 

The medication’s most common side effects are digestive in nature, including nausea, diarrhea, vomiting, and constipation. While many semaglutide side effects will subside with time, it’s good to be aware of what’s expected, what’s not, and what could be a sign of something serious. 

Read on to learn what side effects you can expect when taking semaglutide.

Semaglutide belongs to a class of drugs known as glucagon-like peptide-1 (GLP-1) receptor agonists. GLP-1 medications are typically prescribed to treat type 2 diabetes, obesity, or both. You may recognize these medications by their brand names, which include Trulicity (dulaglutide), Saxenda and Victoza (liraglutide), and dual GLP-1/GIP agonists like Mounjaro and Zepbound (tirzepatide). Semaglutide is the active ingredient behind the popular brand-name drugs Ozempic, Wegovy, and Rybelsus.

As a GLP-1 receptor agonist, semaglutide mimics GLP-1, a gut hormone that helps regulate your appetite and release insulin and glucagon. Your body naturally produces GLP-1 after you eat. GLP-1 then directs your pancreas to release more insulin, and inhibit glucagon production, so your blood sugar stays within a healthy range. GLP-1 also sends satiety signals to your brain when you’re full. Semaglutide also slows down digestion by keeping food in your stomach longer. This makes you feel full sooner, and longer, so you may feel less hungry, eat less, and lose weight as a result. 

Semaglutide is currently available under the brand names Wegovy, Ozempic, and Rybelsus. Generic versions are not yet available. Wegovy and Ozempic are injectable medications, which are injected on a weekly basis. Rybelsus is an oral tablet that is taken daily in the morning.

Semaglutide has proven to be a very effective medication for people looking to manage their type 2 diabetes, cardiovascular risk, and body weight. Semaglutide significantly lowers HbA1c levels and improves glycemic control for people with type 2 diabetes. Within a year and five months, people taking semaglutide lose an average of 7%–17% of their body weight. And, for people with established cardiovascular disease, semaglutide has been shown to reduce their risk of experiencing heart attack, stroke, or death by 20% or more.

Semaglutide has been shown to be a safe and effective drug for many people. While the side effects of semaglutide can feel intense initially, they usually go away with time. In clinical trials, only about 3% to fewer than 7% of people stopped taking semaglutide due to the side effects. 

The most common side effects of semaglutide in adults include the following:

• Nausea

• Vomiting

• Diarrhea

• Abdominal pain

• Constipation

• Headache

• Fatigue 

• Indigestion

• Dizziness

• Bloating

• Belching

• Flatulence 

• Hypoglycemia (in people with type 2 diabetes)

• Stomach flu

• Heartburn (gastroesophageal reflux disease)

When it comes to semaglutide side effects, everyone’s experience can be different, but you can probably expect at least some digestive side effects, given the medication’s impact on your gastrointestinal system. Nausea is the most commonly reported side effect, and roughly one-quarter to one-half of people experience nausea, vomiting, diarrhea, abdominal pain, and/or constipation. Typically, these digestive side effects range from mild to moderate, are most intense when ramping up your dose, and go away with time as your body gets used to semaglutide.

Less common side effects of semaglutide can include hair loss, dysgeusia (changes in taste, such as food tasting metallic or bitter), or a rash or discomfort at the injection site. In clinical trials, 3% or fewer people experienced these side effects.

In rare cases, semaglutide can cause serious side effects that require medical attention, including:

• Pancreatitis (inflammation of the pancreas)

• Diabetic retinopathy (vision loss or damage)

• Hypoglycemia (low blood sugar)

• Increased heart rate

• Kidney problems

• Gallbladder problems

• An allergic reaction

• Depression or suicidal thoughts

If you start to notice signs of any of the above — including difficulty breathing or swallowing, severe rash or itching, feeling faint, changes in your vision, or severe stomach pain — stop taking semaglutide and contact a healthcare provider immediately.

Finally, semaglutide has been linked to the development of thyroid tumors in rats. While it is not known if semaglutide has the same effect in humans, people with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2 (MEN 2) should not take semaglutide.

As we mentioned above, semaglutide’s side effects are usually most pronounced when you are beginning treatment and increasing your dose. With time, as your body gets used to the medication, side effects should lessen in intensity and frequency. In the meantime, here are some tips for managing the side effects you may experience.

How to manage nausea on semaglutide

Nausea is the most common side effect of semaglutide, reported by 16% to 44% of people taking the medication. 

Nausea is most likely to happen when starting treatment with semaglutide, and when increasing your dose. Follow these tips to try and get ahead of it.

• Avoid eating greasy, fried, and sweet foods. Instead, opt for bland, watery, and low-fat foods, such as crackers, toast, rice, and soup. 

• Eat slowly, taking care to savor your food. 

• Avoid lying down after you eat. Instead, get some fresh air outdoors if possible.

• Stay hydrated with ice-cold water and other clear drinks.

How to manage vomiting on semaglutide

Thankfully, vomiting is less likely to occur than nausea, but it is still one of the most common side effects of semaglutide, affecting between 5% to 24% of people, depending on their dosage. As with nausea, vomiting is most likely to occur when you first start taking semaglutide and when increasing your dose.

If you experience vomiting while taking semaglutide, make sure to rehydrate by drinking water, as vomiting can be very dehydrating. Ginger may also help relieve or prevent vomiting. 

If your vomiting is accompanied by severe abdominal pain that does not go away or radiates to your back, contact your healthcare provider immediately. This can be an early warning sign of pancreatitis, a serious inflammation of the pancreas that requires medical attention.

How to manage diarrhea on semaglutide

Diarrhea affects between 8.5% to 30% of people taking semaglutide. Like the other gastrointestinal side effects of semaglutide, diarrhea is most common when beginning treatment and increasing your dose.

Diarrhea is also dehydrating, so refueling with fluids and electrolytes is important. Drink plenty of water. Gatorade or diluted fruit juice are other potential options. Just take care to avoid beverages with too much sugar or caffeine. 

Similar to nausea, adopting a bland diet can help you manage this side effect of semaglutide. Eating low-fiber foods like the following can help firm up your stool.

• Bananas

• Toast

• Oatmeal

• White rice

• Applesauce

• Soup

• Broth

How to manage abdominal pain or bloating on semaglutide

Around 6% to 20% of people experience abdominal pain or discomfort, including bloating, as a side effect of semaglutide. This side effect may result from some of the other discomforting side effects of semaglutide, such as nausea, vomiting, and diarrhea. Treating those side effects with the tips above may help. Using a heating pad on your belly or a warm bath may also relieve you.

Stomach pain typically ranges from mild to moderate and goes away with time. If it becomes persistent and severe, it could be a sign of pancreatitis, a serious inflammation of the pancreas. You may also experience vomiting, and the pain may radiate towards your back. If you experience any of these symptoms, contact your healthcare provider immediately.

How to manage constipation on semaglutide

Up to one in four people may experience constipation while on semaglutide. While side effects like nausea, vomiting, and diarrhea typically go away within a week, constipation can last much longer — for nearly two months, according to a study of people taking a 2.4 mg dosage of semaglutide for weight loss.

If you experience constipation while taking semaglutide, try the following:

• Drink plenty of water

• Exercise regularly

• Eat high-fiber foods like fruits, vegetables, and grains

You can also ask your healthcare provider whether fiber supplements or laxatives could be helpful for you.

How to manage headache on semaglutide

Around 14% of people experience headaches while taking semaglutide, usually on higher dosages of the medication. Headaches can stem from various causes, including dehydration, stress, and skipping meals — which you may do if you’re feeling nauseous from semaglutide.

Over-the-counter pain relievers, like Tylenol (acetaminophen) and Advil (ibuprofen) can help relieve headaches. Staying hydrated can also help prevent headaches. 

Headache can be a sign of hypoglycemia, or low blood sugar, which can be serious for people with type 2 diabetes. Other signs of hypoglycemia include: 

• Dizziness

• Blurred vision

• Anxiety

• Fast heartbeat

• Sweating

• Slurred speech

• Hunger

• Confusion

• Feeling jittery or irritable

• Shakiness

• Weakness 

How to manage fatigue on semaglutide

About one in ten people experience fatigue while taking semaglutide. Fatigue can be a common side effect of many medications, as well as changes in routine or pain — both of which occur when taking semaglutide.

To reduce fatigue, start by getting enough sleep every night. Following a well-balanced diet, staying hydrated, and exercising regularly — all of which are recommended when taking semaglutide —can also help boost your energy.

How to manage indigestion and heartburn on semaglutide

Around 5%–9% of people may experience indigestion or heartburn as a side effect of semaglutide. Certain foods can trigger this feeling, including some of the foods you may want to avoid to relieve nausea anyway, such as greasy, spicy, fried, or acidic foods. You may also want to avoid caffeine and carbonated beverages.

In addition to what you eat, certain behaviors can increase your likelihood of experiencing indigestion or heartburn. Avoid lying down after you eat, and have your last meal at least a few hours before bed. 

How to manage dizziness on semaglutide

Fewer than 10% of people experience dizziness as a side effect of semaglutide. Dizziness can be caused by several things, including dehydration from vomiting and diarrhea. If you feel dizzy, take it easy when getting up after sitting or lying down. Also make sure you’re eating enough and staying hydrated with water.

Dizziness can also be a sign of low blood sugar, or hypoglycemia. If you are taking other medications to manage your type 2 diabetes, such as metformin or insulin, you may have an increased risk of experiencing hypoglycemia. Know the warning signs, which include:

• Headache

• Blurred vision

• Anxiety

• Fast heartbeat

• Sweating

• Slurred speech

• Hunger

• Confusion

• Feeling jittery or irritable

• Shakiness

• Weakness 

How to manage gas and burping on semaglutide

You may notice increased belching and flatulence when taking semaglutide. Up to 7% of people experienced that while taking this medication.

To reduce gassiness while on semaglutide, try:

• Drinking plenty of water

• Eating more slowly, to reduce the amount of air you swallow

• Avoiding carbonated beverages

• Avoiding dairy, if you are lactose intolerant

For most people taking Ozempic, side effects are manageable and lessen with time. If your side effects are severe, or they don’t seem to be going away, contact your health provider.

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Current version

November 14, 2023

Written by

Amelia Willson

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.