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Overview: Niacinamide is used to increase levels of vitamin B3. It is usually very well tolerated, but side effects may include diarrhea, easy bruising, or increased bleeding from wounds. Serious side effects are rare but may include an allergic reaction or liver problems. Before taking niacinamide, tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

Uses

What is niacinamide used for?

Niacinamide is commonly used to increase levels of vitamin B3.

Niacinamide may also be used for other conditions as determined by your health care provider.

How does niacinamide work (mechanism of action)?

Niacinamide, which is a form of vitamin B3, can help increase levels of vitamin B3 in the body.

How is niacinamide supplied (dosage forms)?

Niacinamide, a form of niacin or vitamin B3, is available as a dietary supplement in various strengths and dosage forms to supplement levels of this vitamin.

Another form of niacin is also available in various strengths and dosage forms to supplement levels of this vitamin. It is available both as a dietary supplement and as a prescription for various uses. See niacin for more information.

How should I store niacinamide?

Storage requirements for niacinamide may not be provided with the product packaging. Most products should be kept in a cool, dry location and not in direct sunlight. Be sure to store them out of the reach of children and pets.

Side Effects

What are the most common side effects of niacinamide?

The most common side effects of niacinamide are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Diarrhea
  • Easy bruising
  • Increased bleeding from wounds

There may be other side effects of niacinamide that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of niacinamide?

While less common, the most serious side effects of niacinamide are described below, along with what to do if they happen.

Severe Allergic Reactions. Niacinamide may cause allergic reactions, which can be serious. Stop taking niacinamide and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown, depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking nicotinamide. This may be more likely if you take large doses of niacinamide. Call your health care provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)

Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Warnings & Precautions

Who should not use niacinamide?

Allergies to Ingredients. People who are allergic to any of the following should not take niacinamide.

  • Niacin
  • Niacinamide
  • Nicotinamide
  • Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific niacinamide products they stock.

What should I know about niacinamide before using it?

Follow the recommendations from your health care provider or the instructions that come with the product. 

Keep niacinamide out of the reach of children.

Not all vitamin B3 products are the same. Although dietary supplements containing niacin or niacinamide may be used for similar reasons, they are not the same. Talk with a health care provider before switching from one product to another.

What should I tell my health care provider before using niacinamide?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if niacinamide is right for you.

In particular, make sure that you discuss any of the following.

Other Medicines and Supplements. Niacinamide may interact with other medicines and supplements. Before taking niacinamide, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how niacinamide could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should take niacinamide while you are pregnant or trying to get pregnant.

Breastfeeding. It is not known if niacinamide passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should take niacinamide while breastfeeding.

Interactions

Does niacinamide interact with foods or drinks?

There are no known interactions between niacinamide and foods or drinks.

It is unknown if drinking alcohol will affect niacinamide.

Does niacinamide interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using a medicine, vitamin, or supplement containing niacin, nicotinic acid, or niacinamide before taking niacinamide.

This may not be a complete list of medicines that can interact with niacinamide. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much niacinamide?

If you or someone else has used too much niacinamide, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of niacinamide?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.