What is Niacinamide? Uses, warnings & side effects

Take niacinamide supplements as directed by the package instructions or by a healthcare provider. Do not take more than instructed.

Swallow the niacinamide capsule or tablet whole. Do not crush, break, or chew it.

• Niacinamide tablets may be scored so they can be broken along the score line to reduce the dose.

For niacinamide oral powder, follow the directions on the packaging to prepare a dose. 

• Use caution when measuring a dose—pure niacinamide powder contains large doses (500 mg) in very small measurements (1/5 teaspoon).

Follow the package directions for dosing information and application for niacinamide topical products, including shampoos.

A missed dose of niacinamide should not be a cause for worry for most people. 

For people taking high-dose niacinamide, ask a healthcare provider what to do in case of a missed dose.

As a general rule, a missed dose can be taken at any time if the daily dose does not exceed the maximum dose advised by the packaging or a healthcare professional.

Do not take a double dose of niacinamide to make up for a missed dose.

Niacinamide supplements or topical treatments are not safe for everyone.

Do not take a niacinamide supplement or use a niacinamide topical product if you have allergies to any ingredient in the product.

Do not take niacinamide supplements if you have:

• Severe liver disease

• Active peptic ulcer disease

• Arterial bleeding

Tell any healthcare provider or other healthcare provider who treats you that you are taking niacinamide supplements.

Before taking niacinamide supplements, talk to a healthcare provider first if you have:

• Liver disease

• Gallbladder problems

• Ulcers

• Diabetes

• Uncontrolled angina (chest pain)

• Gout

Before taking niacinamide supplements, get medical advice from a healthcare provider if you are pregnant or breastfeeding.

High-dose niacin supplements can cause liver damage, including severe liver damage and liver failure. When doctors prescribe high-dose niacin supplements, they perform regular blood tests to monitor liver function.

High-dose niacin supplements can also cause other serious problems, including:

• Low blood pressure

• Elevated blood glucose

• Severe muscle damage, a condition that could affect kidney function and kidney health

Taking high-dose niacin supplements may cause flushing and possibly burning, tickling, and itching. This is not life-threatening and usually improves after a few weeks. Flushing is less of a problem when taking niacinamide rather than other niacin supplements.

Because of the risks involved in taking high-dose niacinamide supplements, exercise great caution if you’re using pure niacinamide powder. A very tiny amount of niacinamide powder (1/5 teaspoon) contains a high dose of niacinamide, so exercise great caution when measuring the powder for a dose.

To avoid possible drug interactions, tell healthcare providers you are taking niacinamide supplements.

Before taking high-dose niacinamide supplements, get medical advice from a healthcare provider if you are also taking:

• Blood pressure medications

• Cholesterol-lowering medications

• Aspirin 

• Chest pain medications 

Do not drink alcohol when taking high-dose niacin supplements. The combination increases the risk of liver dysfunction.

If you are prescribed a niacin supplement by a healthcare provider, tell the prescriber about all the prescription medications, over-the-counter drugs, vitamin supplements, and herbal remedies that you’re taking. Tell the healthcare provider about any of the medications listed above, or if you drink regularly.