Niacin Flush: Symptoms, Treatment, Prevention

While no one needs large doses of niacin, some people take it as a supplement to reduce the risk of heart disease and atherosclerosis. Large daily doses of niacin may help to lower LDL cholesterol (the bad cholesterol) and increase HDL cholesterol (the good form of cholesterol). But, it can have some uncomfortable side effects such as experiencing a niacin flush. Here is what you need to know.

What Is Niacin?

Niacin is also known as Vitamin B3. It is found in many types of food, including chicken and turkey breast, beef liver, tuna, salmon, lentils, rice, peanuts, and potatoes, among others. Niacin helps convert food into energy.

Benefits of Niacin Supplements

Most people in the United States and other developed countries get enough niacin in their diet to meet their daily niacin requirements. However, studies have shown that large doses of niacin may help dyslipidemias, which is an imbalance in the fat protein HDL and LDL cholestreol, triglycerides, and total cholesterol.

Symptoms of a Niacin Flush

A niacin flush is a common side effect of taking large doses of niacin (vitamin B3) supplements. The flush happens when the niacin causes the small blood vessels in your skin to dilate so more blood can rush through. It isn't harmful, but it can scare you if you don't know it's coming. Almost everyone who takes large doses of niacin experiences this flush about 30 minutes after taking a large dose (30 to 50 milligrams or more).

The flush includes reddening of the skin accompanied by a burning or itching sensation. Flushing of the face is the most common, but it can also occur in the neck and upper body. The flush gets better over time and is usually gone within an hour or two.

The niacin flush is generally harmless, but may occasionally be accompanied by a headache, dizziness, or drop in blood pressure. If you experience these symptoms with a niacin flush, you should talk to a healthcare provider for advice.

Preventing a Niacin Flush

There are some ways you can help prevent a niacin flush while still reaping the benefits of niacin supplementation. Changing the dose or formulation, taking the supplement with food, and adding adjunct therapies are all ways to help.

Change Your Dose

You won't get the niacin flush reaction after taking multiple vitamins that contain smaller amounts of niacin. It only happens when you take massive doses. The average adult needs about 14 milligrams per day, so megadoses of individual niacin supplements are far more than anyone needs.

Change the Formulation

To avoid or lessen the niacin flush, you could use time-release forms of niacin, which are absorbed and metabolized more slowly than regular niacin.

Another alternative is inositol hexanicotinate, which your body converts to niacin. The conversion is slow enough that it doesn't cause a flush in most people. There has been some evidence that this does not have the same lipid-lowering benefits as niacin. But one review of studies in 2018 shows that it can have a positive effect on LDL (the "bad" form of cholesterol), triglycerides, and total cholesterol among people with metabolic disorders. However it did not have an effect on HDL cholesterol levels.

Take Niacin With an NSAID

Taking a regular aspirin about 30 minutes before taking niacin supplements may also help reduce the discomfort, but probably won't eliminate it altogether. Other NSAIDs can also help manage the symptoms of a niacin flush as well. The key is taking it at the same time as niacin so that its benefits are in effect when the niacin flush starts.

Take Niacin With Food

Eating food when you take your niacin supplement can help slow the absorption of niacin, easing the effects of the niacin flush. If you take niacin in the morning, try to get into the habit of taking it right after you eat breakfast.

Treating a Niacin Flush

If you find yourself dealing with a niacin flush, there is unfortunately not much you can do to treat the symptoms of a single episode. A niacin flush will last up to two hours, although it is possible that symptoms will subside more quickly.

As mentioned, taking an NSAID like aspirin or ibuprofen can help ease some of the symptoms of a niacin flush. The physical discomfort, such as a prickling feeling, can be mitigated by these pain-controlling medications.

Niacin Requirements

Along with thiamin, riboflavin, and others, niacin is an essential B-complex vitamin your body needs to convert macronutrients from the food you eat into energy for daily activities. It also helps your digestive system function properly and supports normal skin and nerve function.

A niacin deficiency results in a disease called pellagra. People with this condition have digestive problems, inflamed skin, and mental impairments. However, pellagra is very rare and currently, it's only seen in undeveloped countries.

The vast majority of people don't need to take niacin supplements because there's plenty of niacin in the foods found in a typical diet, even diets that aren't all that healthy. Nuts, legumes, eggs, poultry, beef, and seafood are all high in niacin, and it's found in smaller amounts in most other foods. So as long as you're eating every day, you're getting plenty of niacin.

A Word From Verywell

Be careful if you're thinking about taking niacin for your high cholesterol levels. Even though the niacin flush is harmless, large doses of niacin can interact with many different medications. Long-term use can cause liver damage, skin rashes, gastrointestinal problems, and elevated blood sugar. Discuss niacin supplements with a healthcare provider before taking them.

Frequently Asked Questions

  • How long does a niacin flush usually last?

    Everyone experiences niacin flushing a little differently, but most niacin flush symptoms do not last longer than about 2.5 hours. However a niacin flush can also resolve in as few as 30 minutes.

  • What are the risks of a niacin flush?

    A niacin flush is generally a harmless side effect of large doses of niacin. However if you experience dizziness, headache, this could be a sign of a drop in blood pressure. Speak to a healthcare professional if you experience these symptoms.

5 Sources
Verywell Fit 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. National Institutes of Health. Office of Dietary Supplements. Niacin Fact Sheet for Health Professionals.

  2. National Institutes of Health. Office of Dietary Supplement. Niacin Consumer Guide.

  3. Mosca S, Araújo G, Costa V, et al. Dyslipidemia diagnosis and treatment: risk stratification in children and adolescents. J Nutr Metab. 2022;2022:4782344. doi:10.1155/2022/4782344

  4. Tabrizi R, Ostadmohammadi V, Lankarani KB, et al. The effects of inositol supplementation on lipid profiles among patients with metabolic diseases: a systematic review and meta-analysis of randomized controlled trials. Lipids Health Dis. 2018;17:123. doi:10.1186/s12944-018-0779-4

  5. Banka SS, Thachil R, Levine A, Lin H, Kaafarani H, Lee J. Randomized controlled trial of different aspirin regimens for reduction of niacin-induced flushing. Am J Health Syst Pharm. 2017;74(12):898-903. doi:10.2146/ajhp160219

By Shereen Lehman, MS
Shereen Lehman, MS, is a former writer for Verywell Fit and Reuters Health. She's a healthcare journalist who writes about healthy eating and offers evidence-based advice for regular people.