Vitamin B3 Facts: Everything You Need to Know

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B vitamins, which are water soluble, help maintain the health of many systems and organs in your body. These include your liver, skin and nervous system. Vitamin B3 in particular, also known as niacin or nicotinic acid, is an important coenzyme that plays a vital role in many metabolic reactions that take place throughout your body. To better understand this vitamin, learn more about the uses, side effects and sources of niacin and niacinamide, along with its recommended dosages.

What Does Vitamin B3 Do?

Just like the other B vitamins, your body needs niacin and niacinamide to convert food into energy through a series of complex metabolic reactions. Because of this vitamin’s contribution to energy production, eating foods rich in vitamin B3 may lead to a slight natural boost in energy. This can help you wake up more easily or get through your day without feeling sluggish.

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While boosting energy is a main function of vitamin B3, another important function is its effectiveness in lowering cholesterol. However, only vitamin B3 in the form of niacin is effective in this way, not niacinamide. Some people with high cholesterol are prescribed a supplement with significant levels of niacin that they can take alone or in combination with other medications.

While there are niacin dietary supplements, these usually contain no more than half of what a prescription drug does. Therefore, only the prescription niacin drugs (not solely dietary supplements) are effective for lowering cholesterol levels. You should consult your physician before starting a niacin supplement, particularly if you’re already taking a cholesterol-lowering prescription medication.

There are also many vitamin B3 supplements on the market. Some are found in supplements that contain a variety of B vitamins, while others are more concentrated with niacin specifically. Speak with your doctor before adding any of these supplements to your daily routine.

Food Sources of Vitamin B3

Most people consume adequate amounts of niacin and niacinamide simply by eating a balanced diet. Vitamin B3 is found in many common foods, such as:

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  • Nutritional yeast
  • Meat and fish
  • Peanuts
  • Bacon
  • Brown rice
  • Avocado
  • Potatoes


If you take an extra moment to read food labels while grocery shopping, you may also notice that many foods are fortified with additional niacin. These can provide even more opportunities for you to incorporate this vitamin into your diet.

Daily Dosage Recommendations for Vitamin B3

The recommended daily dosages for niacin and niacinamide vary based on age, sex and pregnancy or lactation status.

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  • Age 0–6 months: 2 milligrams (mg)
  • Age 7–12 months: 4mg
  • Age 1–3 years: 6mg
  • Age 4–8 years: 8mg
  • Age 9–13 years: 12mg
  • Age 14 and older: 14–16mg, 17mg if lactating and 18mg if pregnant


The conditions that may require differing amounts of vitamin B3 include high cholesterol, diabetes, osteoarthritis, Alzheimer's disease and cataracts. These conditions are generally cause for a higher recommended daily dosage. Always consult a physician before changing your daily dose of vitamin B3 from the basic recommendation for your age group.

Side Effects of Too Much Vitamin B3

Vitamin B3 is a water-soluble vitamin, which means that your body filters it out via urination. That typically prevents any problems with overdoses of vitamin B3. However, extremely high levels of niacin in your body can cause serious health problems.

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Side effects associated with large doses of niacin include skin flushing, peptic ulcers, skin rashes, diarrhea, tachycardia (fast heart rate) and liver damage. This can happen more easily if you’re taking prescription drugs for high cholesterol, so make sure to check with your physician before starting a niacin supplement. In very rare cases, a normal dosage of niacin or niacinamide can cause your skin to become flushed. You might also experience dizziness, intestinal gas or abdominal pain.

There are some conditions that niacin or niacinamide can worsen. If you have liver disease, kidney disease, stomach ulcers or intestinal ulcers, you should avoid vitamin B in excess. Other conditions may be brought on by niacin or niacinamide, including gallbladder disease, stroke and gout. Be sure to consult a physician if you’re at risk for any of these conditions.

Just as there are dangers in getting too much vitamin B3, not getting enough can also harm your health. Pellagra is a condition caused by a deficiency in niacin and an amino acid called tryptophan. Pellagra can cause skin irritation, digestive issues and neurological symptoms. If left untreated, pellagra can eventually cause dementia. Before foods were fortified with niacin, pellagra occurred more commonly than it does today. However, people who are experiencing malnourishment or who have alcoholism may be at a higher risk for developing pellagra due to dietary insufficiencies.

Medical content reviewed by Madeline Hubbard, RN, BSN

Resource Links:

https://medlineplus.gov/druginfo/natural/924.html

https://ods.od.nih.gov/factsheets/Niacin-HealthProfessional/

https://www.hsph.harvard.edu/nutritionsource/niacin-vitamin-b3/

https://www.mountsinai.org/health-library/supplement/vitamin-b3-niacin

https://pubmed.ncbi.nlm.nih.gov/24847436/

https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/expert-answers/niacin-overdose/faq-20058075

https://clinical-nutrition.imedpub.com/nutritional-protocol-for-osteoarthrosisdegenerative-joint-disease.php?aid=18718

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1739176/

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