What You Should Know About Niacin Supplements

A Guide to Choosing the Right One

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Niacin is a form of vitamin B, specifically B3 (nicotinic acid). It is a water-soluble vitamin important for proper cell function in the body. Niacin has been studied for its potential to treat an array of diseases including Alzheimer's disease, cataracts, erectile dysfunction, and sickle cell disease with little success.

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At one time, healthcare providers prescribed niacin to help manage cholesterol in people with cardiovascular disease. However, after a 2011 study published in the New England Journal of Medicine found that niacin provided no benefit to people with high cholesterol, the practice was stopped.

Today, niacin is used mainly to treat niacin deficiency, which if severe can lead to pellagra, a disease characterized by diarrhea, skin lesions, and dementia. Niacin deficiency is most likely to develop as a result of malnutrition, poverty, or chronic alcoholism.

Most people get enough niacin in their diets to prevent a deficiency, particularly from foods like yeast, meat, fish, milk, eggs, green vegetables, and fortified cereal. However, if your healthcare provider or nutritionist says you need more vitamin B3 in your diet, there are things to consider in order to choose the appropriate niacin supplement.

The U.S. Department of Health and Human Services recommends 14 milligrams (mg) of niacin per day for women and 16 mg of niacin day for men from all sources.

Immediate-Release Nicotinic Acid

Immediate-release (IR) nicotinic acid, also known as "fast-release" nicotinic acid, empties the entire dose into the bloodstream as soon as it's swallowed. For this reason, IR nicotinic acid is more likely than other forms of the vitamin to cause side effects.

Some bottles of nicotinic acid may not state if they contain an “immediate-release” or a “sustained-release” (see below) product. If the label doesn't say which form of nicotinic acid is in the bottle, it's safe to assume that it's an IR product.

Extended-Release Nicotinic Acid

This form of nicotinic acid is available by prescription under the brand names Niaspan or Niacor, as well as generically. There also is a controlled-release version called Slo-Niacin that's sold over the counter and may be less expensive.

Extended-release (ER) nicotinic acid is released into the body more slowly than the IR type. Extended-release nicotinic acid may cause side effects but these are likely to be less severe than those associated with the IR form.

Sustained-Release Nicotinic Acid

Sustained-release (SR) nicotinic acid, also known as "timed-release" nicotinic acid, releases nicotinic acid into the body over a period of time rather than all at once. It may still cause side effects, but they're likely to be milder than those brought on by immediate-release supplements.

An SR nicotinic acid supplement will take longer to clear the body than either an IR form or an extended-release (ER) form. For this reason, SR nicotinic acid comes with the risk of liver toxicity.

If you have a liver disease such as cirrhosis or chronic hepatitis B or C infection, it's best not to take sustained-release niacin and to opt for an immediate- or extended-release formulation instead.

Possible Side Effects

Niacin supplements are safe for most people, but there are some potential side effects to be aware of. The most common is flushing—warmth, tingling, itching, and redness of the face, arms, and chest. This symptom may be accompanied by headache, dizziness, rash, and/or a decrease in blood pressure.

The side effects of nicotinic acid can be aggravating and, in some cases, intolerable, but usually subside after a couple of weeks. In the meantime, there are ways to mitigate them.

  • Ease into a full dose. For instance, if you are supposed to take 500 mg per day, take 250 mg the first few days and gradually increase to full strength as tolerated.
  • Switch formulations. If immediate-release niacin causes problems, you may find you can better tolerate an OTC sustained-release formulation or an extended-release formulation since the niacin is delivered gradually rather than all at once.
  • Divide the dose. Rather than take the entire dose all at once, take half in the morning and half at night. (Although you can physically split an immediate-release niacin tablet in two, never cut, chew, or dissolve a sustained- or extended-release tablet.)
  • Avoid alcohol and hot beverages. Both can make side effects worse. Until they fully resolve, cut back on alcohol and hot coffee, tea, or other drinks as much as you can or stop altogether.
  • Take aspirin. Studies have shown that taking aspirin 30 minutes before or at the same time as niacin can decrease the intensity and duration of flushing by 30% to 40%.
  • Try flush-free niacin. This combination supplement contains nicotinamide and inositol hexaniacinate. Although better tolerated than other forms of niacin, research has shown that "flush-free" niacin is no better than a placebo at improving cholesterol and other lipid levels.

High doses of nicotinic acid (more than 3 grams per day) may cause severe side effects, including liver damage, gout, gastrointestinal ulcers, vision loss, high blood sugar, irregular heartbeat, and other serious problems. High-dose niacin also has been associated with an increased risk of stroke.

Dosage and Preparation

There is not enough scientific data to determine a recommended dose of niacin or nicotinic acid. If your healthcare provider prescribes nicotinic acid for you, they will base the dose on factors such as your age, gender, and medical history.

Before taking over-the-counter niacin, talk to your healthcare provider to make sure it makes sense for you to do so. Together you can determine the optimal formulation and dose.

What to Look For

Whether you're buying niacin over the counter or will be taking it by prescription, don't think of it as "only a supplement." It is still a form of medication that has risks and side effects. Report any significant side effects to your healthcare provider right away.

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6 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.
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