Niacin (Vitamin B3)

Medically Reviewed by Jabeen Begum, MD on May 22, 2024
Written by Brigid Galloway Greenwood, R. Morgan Griffin, Amy Gopal
7 min read

Once upon a time, scientists thought there was only one B vitamin. Today we know that there are eight B vitamins -- each with special functions that help your body work properly. Vitamin B3 is also known as niacin. Having enoughniacin in the body is important for general good health because your body uses it to turn food into energy. B3 is also essential for the health of your nervous system, digestive system, and skin.  

We typically get enough niacin from the foods we eat, including red meat, poultry, fish, brown rice, nuts, seeds, legumes, and bananas. Many cereals and breads also have niacin added. 

In higher amounts, niacin may be recommended as a dietary supplement to improve cholesterol levels, slow the progression of certain types of heart disease, and even help prevent memory loss and dementia. However, we are continuing to learn about the risks of excess niacin and how it may impact the body.

Niacin vs. niacinamide

Although the names sound similar, niacin and niacinamide are not the same. Niacinamide is a form of niacin that is made when you have an excess of niacin in your body. As a supplement, niacinamide is often found in products that protect and nourish the skin or treat acne. 

In the early 20th century, scientists discovered that people with niacin deficiency could develop a serious skin condition called pellagra. Thanks to this breakthrough in understanding the role of B vitamins and health, pellagra is now a rare condition, and niacin is an FDA-approved treatment. Over the years, researchers have continued to claim a variety of health benefits related to taking niacin. 

Niacin for high cholesterol 

As a cholesterol treatment, studies show that niacin can boost levels of good HDL cholesterol and lower triglycerides. Niacin also modestly lowers bad LDL cholesterol. It's sometimes prescribed in combination with statins for cholesterol control, such as atorvastatin (Lipitor), fluvastatin (Lescol), pravastatin (Pravachol), rosuvastatin (Crestor, Ezallor), and simvastatin (Flolipid, Zocor).

However, niacin is only effective as a cholesterol treatment at fairly high doses. These doses could pose risks, such as liver damage, gastrointestinal problems, or glucose intolerance. Most recently, researchers found a link between excess niacin and heart disease. So don't treat yourself with over-the-counter niacin supplements. Instead, get advice from your health care professional, who can prescribe FDA-approved doses of niacin instead if recommended.

Niacin for blood pressure

Because of niacin's positive effects on cholesterol levels, there have been numerous studies about how niacin may reduce high blood pressure. Until recently, the association between niacin intake and high blood pressure risk was unknown. However, a 2021 study in Chinese adults found a distinct relationship in the increase in dietary niacin with a decrease in blood pressure levels among people with new-onset hypertension. 

Everyone needs a certain amount of niacin from food or supplements for the body to function normally. This amount is called the dietary reference intake (DRI), a term that is replacing the older and more familiar RDA (recommended dietary allowance). For niacin, the DRIs vary with age and other factors and are given in milligrams of niacin equivalents: 

  • Children: 2-16 milligrams daily, depending on age
  • Men, or those assigned male at birth (AMAB): 16 milligrams daily
  • Women, or those assigned female at birth (AFAB): 14 milligrams daily
  • If pregnant: 18 milligrams daily
  • If breastfeeding: 17 milligrams daily
  • Maximum daily intake for adults of all ages: 35 milligrams daily

Most people can get the niacin they need by eating a healthy diet. If your doctor prescribes niacin, you might want to take it with food. This can prevent upset stomach. 

To reduce flushing -- a harmless but uncomfortable side effect of niacin that describes redness and warmth in the face and neck -- your doctor might recommend taking niacin along with aspirin and avoiding alcohol and spicy foods.

Since niacin can be used in different ways, talk to your doctor about the best dosage for you.

Although niacin is essential for the body, too much of a good thing may cause health issues. You can't overdose by eating too many niacin-rich foods, but taking too much prescription or over-the-counter niacin can be dangerous. For example, a dose between 2,000 and 6,000 milligrams of niacin a day can cause serious side effects. 

Symptoms of a niacin overdose include:

  • Rapid heartbeat
  • Severe skin flushing along with dizziness
  • Nausea and vomiting
  • Diarrhea
  • Abdominal pain
  • Itching
  • Rash
  • Gout

Get medical help immediately if you think you've had too much niacin. 

Niacin occurs naturally in many foods, including greens, meat, poultry, fish, and eggs, although in a fraction of the dose shown to achieve changes in cholesterol. Many products are also fortified with niacin during manufacturing. Good sources for niacin in a typical diet include:

  • Fortified breads and cereals
  • Red meat: Beef, beef liver, pork
  • Poultry
  • Fish
  • Bananas
  • Brown rice
  • Legumes
  • Nuts
  • Seeds

Skin flushing. Niacin can cause flushing, usually around your face and neck, especially when you first begin taking it. Your doctor will probably suggest increasing the dose slowly to reduce this problem. They might also offer a time-release prescription formulation to control flushing. 

Gastrointestinal issues. Niacin can cause upset stomach and diarrhea. However, all of these side effects tend to fade over time.

Other health risks. Niacin does have risks. It can cause liver problems, stomach ulcers, changes to glucose levels, muscle damage, low blood pressure, heart rhythm changes, and other issues. A study published in 2024 found a link between excess niacin and heart disease. Researchers discovered that when the body breaks down niacin, inflammation that damages blood vessels can happen.

People with any health condition including liver or kidney disease, diabetes, high blood pressure, or cardiovascular problems need to talk to a doctor before using niacin supplements. Don't treat high cholesterol on your own with over-the-counter niacin supplements.

Interactions. If you take any medicines or supplements regularly, talk to your doctor before you start using niacin supplements. They could interact with medicines like diabetes drugs, blood thinners, anticonvulsants, blood pressure medicines, thyroid hormones, and antibiotics as well as supplements like ginkgo biloba and some antioxidants. Alcohol might increase the risk of liver problems. Though niacin is often used along with statins for high cholesterol, this combination may increase the risk for side effects. Get advice from your health care professional. 

At the low DRI doses, niacin is safe for everyone. However, at the higher amounts used to treat medical conditions, it can have risks. For that reason, children and anyone who is pregnant or breastfeeding shouldn't take niacin supplements in excess of the DRI unless it's recommended by a doctor. 

People with uncontrolled gout also shouldn't take niacin supplements.

For decades, women who may become pregnant have been advised to take supplements containing vitamin B9 (folic acid) in order to reduce the chance of certain birth defects. Recent research indicates that a lack of niacin may also impact the development of healthy babies. Niacin supplements may be taken during pregnancy and breastfeeding if there's a B3 deficiency; however, experts advise against taking prescription niacin for the treatment of high cholesterol if you're pregnant. Always talk with your doctor before taking niacin supplements if you're pregnant or breastfeeding.

Niacin (vitamin B3) is essential to your health. Although you typically get niacin from the foods you eat, not getting enough can lead to serious conditions. Vitamin B3 has been used as a supplement to lower cholesterol and the risk of certain types of heart disease. It may also have an impact on high blood pressure. You can overdose on over-the-counter or prescription niacin, however. And new research indicates that extra niacin in the body may contribute to heart disease. You should always talk to your doctor before taking niacin supplements, especially if you're pregnant or breastfeeding.

What does taking niacin do for your body?

Having enough niacin in the body is important for general good health because your body uses it to turn food into energy. B3 is also essential for keeping your nervous system, digestive system, and skin healthy. In higher amounts, niacin may also be used as a dietary supplement to improve cholesterol levels, slow the progression of certain types of heart disease, and may even help prevent memory loss and dementia.

Is it OK to take niacin daily?

At the low dietary reference intake (DRI) doses, niacin is safe for everyone. However, at the higher amounts used to treat medical conditions, it can have risks. For that reason, children and those who are pregnant or breastfeeding should not take niacin supplements in excess of the DRI unless it's recommended by a doctor. 

People with any health condition including uncontrolled gout, liver or kidney disease, diabetes, high blood pressure, or cardiovascular problems need to talk to a doctor before using niacin supplements. Don't treat high cholesterol on your own with over-the-counter niacin supplements.

Why is niacin no longer recommended?

We are continuing to learn about how niacin affects the body. A study published in 2024 found a link between excess niacin and heart disease. Researchers discovered that when the body breaks down niacin, inflammation that damages blood vessels can happen.