Rybelsus (semaglutide) is a prescription drug used to manage blood sugar levels in adults with type 2 diabetes. Rybelsus can cause mild to severe side effects that may include constipation and diarrhea.

Rybelsus is used with a nutritious diet and exercise to manage blood sugar in adults with type 2 diabetes.

The active ingredient in Rybelsus is semaglutide. (An active ingredient is what makes a drug work.) The drug comes as a tablet that you swallow.

Keep reading to learn about the common, mild, and serious side effects that Rybelsus can cause. For a general overview of the drug, including details about its uses, see this article.

Some people may experience mild or serious side effects during their Rybelsus treatment. The list below includes the most reported side effects:

* To learn more about this side effect, see “Side effects explained” below.

Nausea, vomiting, and diarrhea are more common when you first start taking Rybelsus or after dose increases. This is because your body needs time to get used to the medication. For most people, these side effects usually go away within a few days or weeks of dose increases.

Rybelsus can cause mild side effects in some people. Examples of mild side effects that have been reported with Rybelsus include:

* To learn more about this side effect, see “Side effects explained” below.

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And do not stop using Rybelsus unless your doctor recommends it.

Rybelsus may cause mild side effects other than the ones listed above. See the Rybelsus medication guide for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Rybelsus, visit MedWatch.

Serious side effects from Rybelsus aren’t common, but they can happen. Serious side effects that have been reported with Rybelsus include:

* Rybelsus has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effects explained” section below.
† An allergic reaction is possible after using Rybelsus. This side effect wasn’t specifically reported in studies of Rybelsus. But it has been reported by people who took the drug after it came on the market. To learn more about this side effect, see “Side effects explained” below.

If you develop serious side effects while taking Rybelsus, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Learn some frequently asked questions and answers about the side effects of Rybelsus.

Does the dose of Rybelsus I take (3 mg, 7 mg, or 14 mg) affect my risk for side effects?

It’s possible. In studies, some people chose to stop taking Rybelsus because of digestion-related side effects.* Of these, more people taking a higher strength of Rybelsus, 14 milligrams (mg), stopped treatment compared with those taking a lower strength, 7 mg.

All strengths of Rybelsus can cause mild or serious side effects. If you’re concerned about side effects with your current dose of the drug, talk with your doctor.

* These included nausea, vomiting, belly pain, diarrhea, constipation, and loss of appetite.

Will Rybelsus cause hair loss?

No, Rybelsus shouldn’t cause hair loss. This wasn’t reported as a side effect in studies of the drug.

However, diabetes, the condition that Rybelsus is used to treat, may be linked to hair loss. Other medications or medical conditions can also cause hair loss.

If you’ve experienced hair loss since starting Rybelsus, talk with your doctor. They may want to check for other causes and discuss your treatment options.

Does Rybelsus make you tired?

It shouldn’t. In studies of the drug, tiredness wasn’t reported as a side effect.

Rybelsus is known to cause nausea and loss of appetite. And not eating enough nutrient-dense calories can cause fatigue (low energy).

To ease nausea, consider trying different foods. Frequently eating snacks instead of three larger meals in a day may help lessen nausea. Choosing nutritious foods over foods with empty calories can give you more energy.

Type 2 diabetes can cause other medical conditions that may result in tiredness, such as heart disease. And some drugs that are used to treat these other conditions can make you feel fatigued, such as blood pressure medications.

If you’re feeling more tired than usual since you started taking Rybelsus, talk with your doctor. They’ll try to find out what’s causing this side effect so it can be treated. And they could change other medications that you might be taking.

How long does Rybelsus stay in your system?

Rybelsus stays in your system for about 5 weeks after your last dose.

If you’re planning a pregnancy, you should wait at least 2 months after stopping Rybelsus before trying to become pregnant. This is because it can take that long before Rybelsus is completely out of your body.

Can you suddenly stop taking Rybelsus?

Yes, you can suddenly stop taking Rybelsus if you and your doctor decide that it isn’t safe or effective for you.

For example, if you develop a serious side effect from Rybelsus, your doctor will have you stop taking it right away. An example is pancreatitis (inflammation in your pancreas).

If you want to stop taking Rybelsus, talk with your doctor first. It’s important that you have a plan in place to manage your blood sugar before stopping any diabetes treatment.

Learn more about some of the side effects Rybelsus may cause.

Weight loss

Rybelsus is not approved by the Food and Drug Administration (FDA) for weight loss. It’s approved to improve blood sugar management in adults with type 2 diabetes.

But the way Rybelsus works in your body may cause weight loss. This drug lowers your blood sugar by stimulating a certain hormone. This hormone slows down how fast your stomach empties after eating, which can help you feel full longer. As a result, you’re more likely to consume fewer calories, which can lead to weight loss.

Also, the more common side effects of Rybelsus are related to digestion. These side effects, which include nausea, belly pain, and reduced appetite, can cause weight loss. But most of these digestion-related side effects are temporary or can be easily managed.

And remember, this drug is meant to be part of a treatment plan that includes eating a balanced diet and exercising. These healthy practices can also contribute to weight loss.

What might help

For some people with type 2 diabetes, weight loss may be a beneficial side effect of Rybelsus. Losing weight can help improve blood sugar management and prevent diabetes from getting worse. According to a recent study, it’s possible that weight loss may even help to reverse type 2 diabetes.

If you’ve recently started taking Rybelsus, it’s common to experience nausea, vomiting, and diarrhea at first. Eating frequent snacks instead of three larger meals in a day may help lessen nausea. Choosing healthy foods can help make sure that your body is still getting some nutrients.

But losing too much weight due to severe vomiting and diarrhea can be harmful. If you’re concerned about weight loss or severe digestion-related side effects from Rybelsus, talk with your doctor. They’ll likely recommend changes to your treatment plan.


Constipation has been reported as a common side effect of Rybelsus.

Everyone experiences some constipation from time to time. But when it’s caused by a medication that you take daily, constipation can become severe. If untreated, constipation can lead to nausea, rectal bleeding, or an intestinal blockage.

Symptoms of constipation may include:

  • having fewer than three bowel movements in a week
  • having stools that are hard to pass
  • passing some stool, but feeling like there’s more that you can’t pass
  • belly pain

What might help

Constipation from Rybelsus might not go away on its own. You may need to take certain steps to relieve constipation and prevent it from coming back.

There are several over-the-counter laxatives that you can use to relieve constipation. Some work within days, others within minutes. Depending on how severe your constipation is, you may want quick relief. Here are a few examples:

  • MiraLAX (polyethylene glycol) is a powder that you mix into a liquid and drink. It usually causes a bowel movement within 1 to 3 days.
  • Dulcolax (bisacodyl) rectal suppository usually causes a bowel movement within 15 to 60 minutes.
  • Fleet Saline Enema rectal enema usually causes a bowel movement within 1 to 5 minutes.

Home remedies may help prevent constipation naturally. Increasing your water intake, eating more vegetables, and exercising are a few ways to get your bowels moving regularly.

If you have questions about which option is best for your constipation, talk with your pharmacist or doctor.

Risk of thyroid cancer

Rybelsus has a boxed warning for the risk of thyroid cancer. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

In animal studies, semaglutide, the active drug in Rybelsus, caused thyroid tumors in mice and rats. But animal studies don’t always reflect what will happen in humans.

It’s not known if Rybelsus causes thyroid cancer in humans. To be safe, you should not take Rybelsus if:

  • you or your family members have had a certain type of thyroid cancer called medullary thyroid carcinoma (MTC)
  • you have a genetic condition called multiple endocrine neoplasia syndrome type 2 (MEN 2)

If you take Rybelsus, you should be aware of the possible symptoms of thyroid cancer. These include:

  • a lump or growth in your neck
  • pain in your neck
  • trouble swallowing
  • trouble breathing
  • a hoarse voice that doesn’t get better

What might help

Before you start Rybelsus, your doctor will want to know your health history. Tell your doctor if you or someone in your family have or has had MTC or MEN2. They’ll likely recommend a different medication for your type 2 diabetes.

If you develop any possible symptoms of thyroid cancer while taking Rybelsus, tell your doctor right away. They will screen you for this cancer.

If you have questions about your risk for thyroid cancer with Rybelsus, talk with your doctor.

Allergic reaction

Like most drugs, Rybelsus can cause an allergic reaction in some people. Allergic reactions weren’t specifically reported in studies of Rybelsus. However, allergic reactions have been reported with its use after the drug came on the market.

Symptoms can be mild or serious and can include:

  • skin rash
  • hives (raised welts on your skin)
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, usually in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest an over-the-counter antihistamine you take by mouth, such as Benadryl (diphenhydramine), or a product you apply to your skin, like hydrocortisone cream, to manage your symptoms.

If your doctor confirms you had a mild allergic reaction to Rybelsus, they’ll decide if you should continue using it.

If you have symptoms of anaphylaxis (a severe allergic reaction), such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you had a serious allergic reaction to Rybelsus, they may have you switch to a different treatment.

Keeping track of side effects

During your Rybelsus treatment, consider keeping notes on any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful to do when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things like:

  • what dose of drug you were taking when you had the side effect
  • how soon after starting that dose you had the side effect
  • what your symptoms were from the side effect
  • how it affected your daily activities
  • what other medications you were also taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help your doctor learn more about how Rybelsus affects you. And your doctor can use this information to adjust your treatment plan if needed.

Rybelsus comes with several warnings.

Boxed warning: Risk of thyroid cancer

Rybelsus has a boxed warning for the risk of thyroid cancer. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

If you have a personal or family history of thyroid cancer, your doctor will likely recommend a treatment other than Rybelsus for your type 2 diabetes. Otherwise, your doctor will monitor you for symptoms of thyroid cancer while you’re taking Rybelsus treatment.

To learn more, see the “Side effects explained” section above.

Other warnings

Rybelsus may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Rybelsus. The list below includes factors to consider.

Eye problems related to diabetes. Diabetes can lead to diabetic retinopathy. This is a condition that damages the blood vessels in your retina. In studies, some people with diabetic retinopathy who took Rybelsus developed more severe problems related to this eye condition. If you have diabetic retinopathy, talk with your doctor before starting Rybelsus treatment. They may want to have your eyes checked more often while you’re taking this drug.

Risk of low blood sugar. Although not common, Rybelsus can cause hypoglycemia (low blood sugar) as a serious side effect. If you’re taking certain diabetes medications, Rybelsus may increase this risk. Examples include insulin and sulfonylureas such as Amaryl (glimepiride). Be sure to tell your doctor about other diabetes medications you take. If your doctor recommends you take Rybelsus with your other diabetes medications, they may have you check your blood sugar levels more often.

Kidney problems. Short-term kidney damage and worsening of long-term kidney disease have been reported with the use of Rybelsus. Symptoms include nausea, vomiting, diarrhea, and dehydration. If you’ve had kidney problems, be sure to tell your doctor before taking Rybelsus. They may check your kidneys with a blood test before you start the drug. They might also recheck your kidneys during treatment, especially if you develop severe vomiting or diarrhea. These side effects can lead to dehydration, which can be harmful if you have kidney problems.

Pancreas problems. In rare cases, pancreatitis (inflammation in your pancreas) has been reported with Rybelsus. If you have a history of pancreas problems, talk with your doctor. They’ll determine whether it’s safe for you to take Rybelsus.

Allergic reaction. If you’ve had an allergic reaction to Rybelsus or any of its ingredients, you should not take Rybelsus. Ask your doctor what other medications are better options for you.

Alcohol and Rybelsus

Rybelsus doesn’t interact with alcohol.

However, you should take Rybelsus on an empty stomach. This means that if you drink, you should not drink alcohol before it’s time for your dose. And you should not consume anything other than 4 ounces (about half a cup) of plain water in the 30 minutes after your dose. This includes other medications.

Pregnancy and breastfeeding while taking Rybelsus

Rybelsus treatment hasn’t been studied in pregnant people. So it’s not known whether it can be harmful to take during pregnancy.

Its effects on breastfeeding and breast milk are also unknown.

If you’re pregnant or breastfeeding or planning to become pregnant or breastfeed, talk with your doctor. They’ll help you plan how best to manage your blood sugar levels during this time.

Rybelsus can be an effective treatment for improving blood sugar management in adults with type 2 diabetes. It’s meant to be used together with a nutritious diet and exercise.

As with many other drugs, Rybelsus can cause side effects in some people. You should talk with your doctor to find out if Rybelsus is safe for you. Some questions that you may want to ask your doctor include:

  • How long do Rybelsus side effects last?
  • Do any of my other medications increase my risk for side effects from this drug?
  • With my current health and medical history, am I at higher risk for serious side effects from Rybelsus?

To learn more about Rybelsus, see these articles:

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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.