Tresiba (Insulin Degludec) - Subcutaneous

What Is Tresiba?

Tresiba (insulin degludec) injection is a long-acting insulin product used to lower blood sugar (glucose) levels in people with type 1 or 2 diabetes. It is similar to the natural insulin found in your body. Tresiba works by moving sugar from your blood into different parts of your body, where it can be used for energy. It also decreases how much sugar your liver produces.

Tresiba is a prescription product, so you and your healthcare provider will decide if Tresiba should be added to your diabetes treatment plan. Tresiba is injected under the skin (subcutaneously) and available as a vial or a prefilled dosing pen (Tresiba FlexTouch).

Drug Facts

Generic Name: Insulin degludec

Brand Name(s): Tresiba

Drug Availability: Prescription

Administration Route: Subcutaneous

Therapeutic Classification: Antidiabetic

Available Generically: No

Controlled Substance: N/A

Active Ingredient: Insulin degludec

Dosage Form(s): Solution for injection

What Is Tresiba Used For?

Tresiba is used to lower blood sugar in people with type 1 or type 2 diabetes. The Food and Drug Administration (FDA) approved Tresiba for use in adults and children 1 year and older.

People with type 1 diabetes don’t make enough insulin, which causes blood sugar levels to become too high. If you have type 1 diabetes, you’ll need to use Tresiba with short-acting insulin to control your blood sugar.

People with type 2 diabetes have trouble keeping their blood sugar in a healthy range because their bodies do not use insulin normally. If you have type 2 diabetes, your healthcare provider may prescribe Tresiba with short-acting insulin or with oral diabetes medications.

Uncontrolled diabetes and high blood sugar can cause serious and sometimes life-threatening problems. Over time, you may be at increased risk of heart disease, stroke, kidney problems, nerve damage, and eye problems. Tresiba can help lower your risk, especially when used with lifestyle changes, like diet and exercise.

Tresiba (Insulin Degludec) Drug Information - Showing some of the inner workings of the body including the liver and glucose in the bloodstream

Verywell / Dennis Madamba

How to Take Tresiba

Tresiba is a solution (liquid) that you inject under your skin (subcutaneously) using either a vial or prefilled dosing pen (Tresiba FlexTouch). Because it’s long-acting insulin, you’ll only need to take it once daily. Take your dose at the same time each day.

If your healthcare provider has prescribed the vial, you’ll need to use a needle and syringe to draw up and administer your dose. If your prescription is for the pen, you’ll apply a new needle tip onto the pen for each dose.

Before using Tresiba, your healthcare provider will show you how to draw up and administer your dose correctly. Be sure to let them know if you are confused about any steps. Injecting too much or too little insulin can be dangerous, so it’s important to get it right.

Follow these steps to ensure you use Tresiba safely and effectively:

  • Always wash your hands with soap and water before administering Tresiba. 
  • Before preparing your dose, check the prescription label to ensure you have the correct insulin—mainly if you use more than one type of insulin. 
  • Inspect Tresiba before using. The liquid should be clear and colorless. Do not use it if the liquid appears cloudy, has particles, has changed color, or if the vial or pen is cracked, damaged, or leaking fluid.
  • Do not shake or roll the vial before using.
  • Select your injection site and wipe your skin with an alcohol swab. Let your skin dry before injecting your dose. 
  • Inject Tresiba into the upper arm, thigh, or stomach. Be sure to rotate sites to prevent a skin reaction. 
  • Inject your dose exactly as instructed by your healthcare provider.
  • After administering your dose, throw the used needle and syringe away into a sharps disposal container.

If you do not have an FDA-cleared sharps container, you may use a household container that is puncture-resistant, leak-resistant, made of heavy-duty plastic, and sealable. An empty laundry detergent container is one option. When your sharps disposal container is almost full, follow the instructions on this FDA website to properly dispose of the container based on where you live.

When using Tresiba, remember not to:

  • Mix Tresiba with any other insulin products or solutions
  • Roll or shake the vial. This can create air bubbles or foam and cause you to draw the wrong amount of insulin.
  • Inject into tender, bruised, scaly, or hard skin. Avoid pits, lumps, scars, and damaged skin.
  • Share or reuse needles or syringes. Doing so can lead to a serious infection. Never share your Tresiba FlexTouch pen with anyone else.


Keep unused pens and vials in the refrigerator. Store Tresiba vials in their original carton to protect them from light. Do not freeze Tresiba or use it if it has been previously frozen.

Once you begin using a vial or pen, you may store it at room temperature (between 68 and 72 degrees F) away from heat and light or in the refrigerator. Throw away used pens and vials after 56 days (eight weeks), even if there is still insulin left or the expiration date has not yet passed.

Keep Tresiba, and all of your medications, in a safe location, out of the reach of children and pets.

How Long Does Tresiba Take to Work?

After injecting your dose, Tresiba lowers blood sugar within one hour. Because Tresiba is a long-acting insulin, it will continue to control blood sugar levels evenly for 24 hours, but its effect can last up to 42 hours.

What Are the Side Effects of Tresiba?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider. You may report side effects to the FDA at or 1-800-FDA-1088.

Common Side Effects

Tresiba is an important part of controlling your diabetes, but side effects can occur. Let your healthcare provider know if you notice any of these common side effects:

  • Reactions where you inject the dose such as bruising, pain, bleeding, redness, bumps, swelling, changes in skin color, warmth, itching, and rash 
  • Skin thickening or pits where you inject the dose 
  • Swelling of your hands or feet  
  • Weight gain

Severe Side Effects

Tresiba, like other insulin products, may cause severe and sometimes life-threatening reactions. Let your healthcare provider know right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or think you’re having a medical emergency. Series side effects can include:

  • Low blood sugar
  • Low potassium in your blood
  • Heart failure
  • Allergic reaction

Low Blood Sugar

Low blood sugar (hypoglycemia) is the most common side effect of Tresiba. Very low blood sugar can be dangerous and sometimes deadly. Before starting Tresiba, talk with your healthcare provider about what to do if low blood sugar occurs. They may recommend drinking juice or taking glucose tablets.

Signs of low blood sugar include:

  • Anxiety, irritability, or mood changes 
  • Blurred vision
  • Confusion 
  • Dizziness or feeling lightheaded 
  • Fast heartbeat 
  • Headache 
  • Hunger
  • Shakiness
  • Slurred speech 
  • Sweating

If low blood sugar is left untreated, seizures or a coma can occur. Check your blood sugar and contact your healthcare provider right away if you think your blood sugar is too low.

Low Potassium

Tresiba may lower potassium blood levels (hypokalemia). If potassium becomes too low, heart and breathing problems can occur and may even result in death. Your healthcare provider may monitor your potassium levels with a blood test, especially if you take other medications that can decrease potassium.

Heart Failure

Taking Tresiba with certain diabetes medications called thiazolidinediones (TZDs) may increase your risk of developing heart failure. If you already have heart failure, taking Tresiba with TZDs can worsen it. Let your healthcare provider know if you notice any signs of heart failure, including:

  • Shortness of breath
  • Tiredness
  • Swelling of your ankles or feet
  • Sudden weight gain

Allergic Reaction

Severe and life-threatening allergic reactions have occurred in people taking Tresiba. Seek medical care right away if you develop:

  • Difficulty breathing or swallowing
  • Rash, hives, or itching 
  • Shortness of breath 
  • Swelling of the eyes, face, lips, tongue, or throat
  • Wheezing

Report Side Effects

Tresiba may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Tresiba Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For injection dosage form (solution):
    • For Type 1 diabetes:
      • Adults and children 1 year of age and older—Dose is based on your blood sugar and must be determined by your doctor.
      • Children up to 1 year of age—Use and dose must be determined by your doctor.
    • For Type 2 diabetes:
      • Adults and children 1 year of age and older—Dose is based on your blood sugar and must be determined by your doctor.
      • Children up to 1 year of age—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of Tresiba, take it as soon as you remember and then continue with your normal dosing schedule. Make sure there are at least eight hours between your doses.

If your child is using Tresiba, call their pediatrician for instructions on measuring blood sugar levels more frequently until it is time for their next dose.

Overdose: What Happens If I Take Too Much Tresiba?

Taking more than your prescribed dose of Tresiba may cause low blood sugar (hypoglycemia) or low blood potassium (hypokalemia). This can sometimes cause severe and life-threatening effects.

Signs of low blood sugar include:

  • Anxiety, irritability, or mood changes 
  • Blurred vision
  • Coma 
  • Confusion 
  • Dizziness or feeling lightheaded 
  • Fast heartbeat 
  • Headache 
  • Hunger
  • Seizures 
  • Shakiness
  • Slurred speech 
  • Sweating

Signs of low potassium include:

  • A heartbeat that does not feel normal 
  • Muscle cramps
  • Muscle pain or weakness

What Happens If I Overdose on Tresiba?

If you think you or someone else may have overdosed on Tresiba, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses, has a seizure, has trouble breathing, or can’t wake up after taking too much Tresiba, call 911 immediately.


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Never share insulin pens with others under any circumstances. It is not safe for one pen to be used for more than one person. Sharing needles or pens can result in transmission of hepatitis viruses, HIV, or other bloodborne illnesses.

Your doctor will want to check your or your child's progress at regular visits, especially during the first few weeks you use this medicine. Blood and urine tests may be needed to check for unwanted effects.

It is very important to follow carefully any instructions from your health care team about:

  • Alcohol—Drinking alcohol may cause severe low blood sugar. Discuss this with your health care team.
  • Other medicines—Do not take other medicines during the time you or your child is taking insulin degludec unless they have been discussed with your doctor. This especially includes nonprescription medicines such as aspirin, and medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems.
  • Counseling—Other family members need to learn how to prevent side effects or help with side effects if they occur. Also, patients with diabetes may need special counseling about diabetes medicine dosing changes that might occur because of lifestyle changes, such as changes in exercise and diet. Furthermore, counseling on contraception and pregnancy may be needed because of the problems that can occur in patients with diabetes during pregnancy.
  • Travel—Keep a recent prescription and your medical history with you. Be prepared for an emergency as you would normally. Make allowances for changing time zones and keep your meal times as close as possible to your usual meal times.

In case of emergency—There may be a time when you need emergency help for a problem caused by your diabetes. You need to be prepared for these emergencies. It is a good idea to:

  • Wear a medical identification (ID) bracelet or neck chain at all times. Also, carry an ID card in your wallet or purse that says that you have diabetes and a list of all of your medicines.
  • Keep an extra supply of insulin degludec and syringes with needles or injection devices on hand in case high blood sugar occurs.
  • Keep some kind of quick-acting sugar handy to treat low blood sugar.
  • Have a glucagon kit and a syringe and needle available in case severe low blood sugar occurs. Check and replace any expired kits regularly.

Too much insulin degludec can cause hypoglycemia (low blood sugar). Low blood sugar also can occur if you use insulin degludec with another antidiabetic medicine, changes in insulin regimen (eg, insulin strength, type of insulin, injection site), delay or miss a meal or snack, exercise more than usual, or drink alcohol. Symptoms of low blood sugar must be treated before they lead to unconsciousness (passing out). Different people may feel different symptoms of low blood sugar. It is important that you learn which symptoms of low blood sugar you usually have so that you can treat it quickly.

Symptoms of low blood sugar include: anxiety, behavior change similar to being drunk, blurred vision, cold sweats, confusion, difficulty in thinking, dizziness or lightheadedness, drowsiness, excessive hunger, fast heartbeat, headache, irritability or abnormal behavior, nervousness, nightmares, restless sleep, shakiness, slurred speech, and tingling in the hands, feet, lips, or tongue.

If symptoms of low blood sugar occur, eat glucose tablets or gel, corn syrup, honey, or sugar cubes, or drink fruit juice, non-diet soft drink, or sugar dissolved in water to relieve the symptoms. Also, check your blood for low blood sugar. Get to a doctor or a hospital right away if the symptoms do not improve. Someone should call for emergency help immediately if severe symptoms such as convulsions (seizures) or unconsciousness occur. Have a glucagon kit available, along with a syringe and needle, and know how to use it. Members of your household also should know how to use it.

Hyperglycemia (high blood sugar) may occur if you do not take enough or skip a dose of your antidiabetic medicine or insulin, changes in insulin regimen, you overeat or do not follow your meal plan, have a fever or infection, or do not exercise as much as usual.

Symptoms of high blood sugar include: blurred vision, drowsiness, dry mouth, flushed, dry skin, fruit-like breath odor, increased urination, ketones in the urine, loss of appetite, stomachache, nausea or vomiting, tiredness, troubled breathing (rapid and deep), unconsciousness, and unusual thirst.

If symptoms of high blood sugar occur, check your blood sugar level and then call your doctor for instructions.

This medicine can cause low blood sugar. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and require immediate medical attention. Tell your doctor right away if you or your child have a rash, itching, swelling of the face, tongue, and throat, trouble breathing, or chest pain after you use the medicine.

This medicine may cause low levels of potassium in your blood. Do not use medicines, supplements, or salt substitutes that contain potassium unless you have discussed this with your doctor.

Using this medicine together with other diabetes medicine (eg, pioglitazone, rosiglitazone, Actos®, Actoplus Met®, Avandia®) may cause serious heart problems or edema (fluid retention). Check with your doctor immediately if you are rapidly gaining weight, having chest pain or discomfort, extreme tiredness or weakness, trouble breathing, uneven heartbeat, or excessive swelling of the hands, wrist, ankles, or feet.

What Are Reasons I Shouldn’t Take Tresiba?

You should not take Tresiba if you have a low blood sugar episode(hypoglycemia). Ask your healthcare provider when it is OK to restart your Tresiba. Also, don’t take Tresiba if you have an allergy to Tresiba or any ingredient in Tresiba. Ask your pharmacist for a complete list of all the ingredients if you are unsure.

What Other Medications Interact With Tresiba?

Many medications may interact with Tresiba. Let your healthcare provider know about all your medicines, including over-the-counter herbal products and supplements. 

Some drugs may increase the risk of low blood sugar if taken with Tresiba. Your healthcare provider may recommend a lower dose of Tresiba or more frequent blood sugar monitoring.

These medications include:

Other drugs may prevent Tresiba from working as well. These include:

  • Certain diuretics (or “water-pills”) like Microzide (hydrochlorothiazide) and Thalitone (chlorthalidone)
  • Certain antipsychotics, like Zyprexa (olanzapine) and Clozaril (clozapine)
  • Corticosteroids (steroids) like Rayos (prednisone) 
  • Estrogen and birth control pills 
  • Some HIV medications 

Some medications may block the signs of low blood sugar. You may need to check your blood sugar levels more frequently if you take:

This is not a complete list of all the medications that may interact with Tresiba. Always keep an up-to-date list of all the medicines you take, and share this information with your healthcare practitioner or pharmacist any time there are changes.

What Medications Are Similar?

Tresiba is a long-acting insulin, which means it slowly releases insulin into your body to help control your blood sugar levels throughout the day. Tresiba is slightly longer-acting than other long-acting insulin. If you take your Tresiba dose a few hours late, your blood sugar levels are not likely to be affected that much.

Other long-acting insulins include:

  • Levemir (insulin detemir)
  • Lantus, Semglee, Basaglar, and Toujeo (insulin glargine)

This is a list of long-acting insulin products also prescribed to treat diabetes. It is not a list of drugs recommended to take with Tresiba. You should not take these drugs together. Ask your healthcare provider if you have any questions about your medications.

Frequently Asked Questions

  • What is Tresiba used for?

    Tresiba is FDA-approved to lower blood sugar (glucose) levels in people with type 1 and type 2 diabetes. Tresiba is approved for adults and children 1 year and older.

  • How does Tresiba work?

    Tresiba is a long-acting insulin product similar to the natural insulin found in your body. Tresiba lowers blood sugar by moving sugar in the blood to other areas of the body to be used for energy. Tresiba also decreases how much sugar your liver produces.

  • How long does it take for Tresiba to work?

    Tresiba begins to lower blood sugar within one hour and lasts throughout the day.

  • What are the side effects of Tresiba?

    The most common side effect of Tresiba is low blood sugar (hypoglycemia). Signs of low blood sugar include dizziness, lightheadedness, blurred vision, anxiety, irritability, sweating, slurred speech, hunger, confusion, shakiness, headache, and a fast heartbeat. Before starting Tresiba, talk with your healthcare provider about monitoring your blood sugar and what to do if low blood sugar occurs.

  • Where should Tresiba be injected?

    Inject Tresiba under the skin (subcutaneously) in the upper arm, thigh, or stomach. Rotate the site each time you inject a dose to prevent skin reactions.

How Can I Stay Healthy While Taking Tresiba?

Finding out you need to start insulin can be scary—especially if you've never used an injectable medication before. Ensuring you receive the proper training can help alleviate some fears. 

Before starting Tresiba, make sure you understand how to measure and administer your dose correctly. Talk with your healthcare provider about how often you'll need to monitor your blood sugar and what the values mean. Know the signs of hypoglycemia and have a treatment plan in place. Following these steps can help you effectively manage your diabetes and decrease the risk of side effects.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some drug content, as indicated on the page.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Tresiba label.

  2. MedlinePlus. Insulin degludec (rDNA origin) injection.

  3. Food and Drug Administration. Sharps disposal containers.

  4. Aye MM, Atkin SL. Patient safety and minimizing risk with insulin administration - role of insulin degludec. Drug, Healthcare and Patient Safety. 2014;6:55—67. doi:10.2147/DHPS.S59566

By Christina Varvatsis, PharmD
Christina Varvatsis is a hospital pharmacist and freelance medical writer. She is passionate about helping individuals make informed healthcare choices by understanding the benefits and risks of their treatment options.