If you have diabetes, your doctor might suggest Toujeo (insulin glargine) as a treatment option for you. Knowing Toujeo’s possible side effects can help you and your doctor decide whether to add it to your treatment plan.

Toujeo is a prescription medication that’s used to treat type 1 or type 2 diabetes in adults and some children. Toujeo is not used to treat diabetic ketoacidosis.

Toujeo is a long-acting insulin that’s available as a liquid solution. It comes in prefilled pens (Toujeo SoloStar or Toujeo Max SoloStar) that you use to inject the drug under your skin.

If Toujeo works to manage your blood sugar, your doctor may recommend that you use it long term to treat your diabetes.

For more information about Toujeo, see this in-depth article.

Mild or serious side effects can be caused by Toujeo. Continue reading to learn more.

“Mild or serious side effects may occur during the Toujeo treatment. Some of Toujeo’s reported side effects include:”

The side effects explained section is where you can learn more about this side effect.

There are other possible side effects of Toujeo.

Mild side effects from Toujeo are the majority. Mild side effects have been reported with Toujeo.

The side effects explained section is where you can learn more about this side effect.

“These side effects should be temporary. Some may be easy to manage. If you have any symptoms that bother you, talk to your doctor or pharmacist. Unless your doctor recommends it, don’t stop using Toujeo.”

Toujeo may cause mild side effects other than the ones listed above. See the Toujeo prescribing information for details.

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

It is possible to develop serious side effects from Toujeo. There have been serious side effects with this drug.

The side effects explained section is where you can learn more about this side effect.

If you develop serious side effects, you should call your doctor. If the side effects seem life threatening or if you think you have a medical emergency, immediately call the emergency number.

Get answers to questions about Toujeo.

Does Toujeo cause diarrhea?

No, diarrhea isn’t a side effect of Toujeo. In studies, people receiving this medication didn’t report having diarrhea.

But other diabetes medications, such as Fortamet (metformin), may cause diarrhea.

If you have a problem with your scurvy while you are receiving Toujeo, talk to your doctor. They may be able to recommend ways to stop the side effect from happening.

Is joint pain a side effect of Toujeo?

No, joint pain isn’t a side effect of Toujeo. Joint pain wasn’t reported in studies of people receiving this drug.

But it’s possible for other medications that treat diabetes to cause joint pain. For example, Lantus (insulin glargine)* can cause joint pain.

Ask your doctor about what is causing the joint pain. They should be able to recommend the best treatment.

* Toujeo and Lantus both have the same active ingredient, insulin glargine. But studies of Lantus reported some different side effects from those reported in studies of Toujeo.

Does Toujeo cause sleepiness?

No, Toujeo shouldn’t cause you to feel sleepy. Studies of people receiving Toujeo didn’t report this side effect.

But it’s possible to feel sleepy due to diabetes itself. For example, high or low blood sugar can cause you to feel more tired than usual.

If you’re experiencing sleepiness during Toujeo treatment, talk with your doctor. They may recommend testing your blood sugar levels when you’re sleepy to see if they’re high or low. Your doctor may also recommend ways to decrease the sleepiness that you’re feeling.

There are some side effects Toujeo may cause.

Weight gain

You may have weight gain from receiving Toujeo. This medication, along with other insulin treatments, may cause weight gain to occur. This is a common side effect reported by people taking Toujeo in studies.

What might help

If you have unexpected weight gain, talk with your doctor. In some cases, weight gain may be due to other conditions, such as heart failure. Your doctor may evaluate you to be sure nothing else is causing the weight gain. They may also be able to recommend ways to maintain a moderate weight.

For tips on managing weight gain while taking insulin, such as Toujeo, see this article.

Injection site reactions

You may have injection site reactions from Toujeo. These are side effects that occur in an area where you injected the drug. In studies, injection site reactions were one of the most commonly reported side effects.

Injection site reactions to watch out for include:

What might help

If you experience a reaction at the site of a Toujeo injection, talk with your doctor. They’ll check to make sure that you’re not having an allergic reaction. Then they’ll be able to recommend ways to treat this side effect. For example, they may recommend taking an over-the-counter (OTC) medication, such as Benadryl (diphenhydramine), to ease your symptoms.

Low blood sugar

Toujeo can cause low blood sugar. This is a common side effect of the drug, and in some cases, it can be severe or even life threatening.

You should know the symptoms of low blood sugar so that you can treat it. Symptoms to watch for include:

What might help

Your doctor will likely discuss with you how to prevent and treat low blood sugar. They may recommend that you keep a record of your blood sugar levels.

If you develop symptoms of low blood sugar, eat 15 grams (g) of carbohydrates. Then after 15 minutes, test your blood sugar level to see if it’s increased to normal. If it’s still low, you should repeat this process.

Some food and drinks contain 15 grams of carbohydrates.

  • 4 ounces of juice or regular soda.
  • A small amount of sugar, honey, or corn syrup.
  • Hard candy or beans.

Talk to your doctor about how to prevent or treat low blood sugar.

Allergic reaction

Like most drugs, Toujeo can cause an allergic reaction in some people.

Mild or serious symptoms can be present.

What might help

If you have a mild rash, call your doctor. They may suggest an OTC antihistamine, such as Benadryl, to manage your symptoms. They may recommend a product that you use on your skin.

If your doctor confirms you had an allergic reaction to Toujeo, they will decide if you should continue using it.

If you have a severe allergic reaction, you should call the emergency number. These symptoms could be life threatening and need immediate medical care.

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

Keeping track of side effects

Keep notes on any side effects you have during your treatment. You can share this information with your doctor. This is helpful when you are starting to use a combination of treatments.

Side effect notes can include things.

  • When you had the side effect, what dose were you taking?
  • How soon after starting that dose did you experience side effects?
  • What were your symptoms after the side effect?
  • How did it affect your daily activities?
  • What other drugs were you taking?
  • Other information is important to you.

Sharing notes with your doctor will help him learn more about how Toujeo affects you. Your doctor can use this information to adjust your treatment plan.

If you have a medical condition that affects your health, Toujeo may not be right for you. Before Toujeo treatment, you should talk to your doctor about your health history. The list has factors to consider.

Kidney problems. If you have kidney problems, Toujeo can increase your risk of low blood sugar. Before starting Toujeo treatment, tell your doctor about any kidney problems you may have. They’ll likely recommend that you monitor your blood sugar levels more often throughout treatment.

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

Liver problems. Before starting Toujeo treatment, discuss any liver problems that you have with your doctor. Liver problems may increase your risk of low blood sugar. If you have liver problems, your doctor may recommend that you monitor your blood sugar levels more often throughout treatment.

Heart problems. If you have heart failure, tell your doctor. Using Toujeo while taking another type of diabetes medication called thiazolidinediones (TZDs) may worsen this condition. Examples of TZDs include Actos (pioglitazone) and Avandia (rosiglitazone). Your doctor may recommend monitoring your heart failure more often. Or they may suggest taking a medication other than the TZD for your diabetes.

Alcohol use and Toujeo

If you drink alcohol, your doctor will probably recommend against it. Alcohol may affect the way Toujeo works.

Talk to your doctor about the effects of alcohol.

Pregnancy and breastfeeding while receiving Toujeo

It is not known if Toujeo is safe to use during pregnancies or breastfeeding.

If you’re pregnant or breastfeeding, or planning to become pregnant or breastfeed, talk with your doctor before starting Toujeo treatment. They can help you determine the right treatment for your diabetes during pregnancy or breastfeeding.

Side effects from Toujeo are mild. Severe side effects from the drug are rare.

You should talk to your doctor about possible side effects of Toujeo. Some questions to get you started.

  • Do my other medical conditions increase my risk of side effects?
  • What is the best way to treat side effects from Toujeo?
  • What should I do if I get pregnant?
  • How can I prevent side effects from occurring?

For details about Toujeo’s recommended dosages, you can see this in-depth article.

If you have type 2 diabetes, sign up for Healthline’s online newsletter to learn more about managing your condition. You can also get resources and advice from others living with this condition in the Bezzy T2D community.


Am I at an increased risk of side effects if I use Toujeo with other medications for my diabetes?



Taking other medications for diabetes together with Toujeo may increase your risk of low blood sugar. This is the most common side effect to occur when using any insulin, including Toujeo. In rare and severe cases, low blood sugar can be life threatening. It’s recommended that you talk with your doctor about how to recognize and manage this side effect.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

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.