The ABCs of Vitamins: Vitamin B3 (Niacin)

The ABCs of Vitamins: Vitamin B3 (Niacin)

Vitamin B3 (Nicotinic Acid): Niacin is one of the most abundant vitamins found naturally in food. It is essential for proper metabolism, nerve transmission, blood clotting and many other functions. It plays a major role in energy production and cellular respiration.

Niacin helps maintain normal blood sugar levels and prevents diabetes mellitus type 2 or diabetic ketoacidosis. It is also involved in the synthesis of steroid hormones such as testosterone and estrogen. Niacin deficiency causes fatigue, depression, irritability, nervousness, weight loss and other symptoms. Niacin supplementation can prevent these problems.

How Much Is Enough?

It’s not easy to get enough niacin from your diet alone. However, it is possible if you are taking a supplement containing niacin like nicotinic acid or nicotinamide riboside (NR). NR supplements are available over the counter without a prescription. They contain either 50 mg of nicotinic acid or 200 mg of NR. Nicotinic acid is an organic compound found in plants, fruits and vegetables including citrus fruit, apples, pears, plums and cherries. It is used as a flavoring agent in some foods and beverages. You probably get enough nicotinic acid from your diet.

What Happens If You Don’t Get Enough?

Your body will take what it needs from your diet and excrete the rest as waste. However, if you are not consuming enough niacin to begin with, then you may develop a deficiency. This is especially true if you are consuming a lot of enzymes that break down proteins, such as if you suffer from liver disease. You may also not be able to absorb enough niacin from your digestive tract. Pernicious anemia is a disease in which your body does not have enough vitamin B12 to produce red blood cells. Without adequate red blood cells, it is difficult for your body to get oxygen into your tissues and deliver nutrients.

What Happens If You Get Too Much?

There is no known toxicity associated with niacin. Taking more than the recommended dose will not increase its effectiveness or speed up your metabolism, it will just give you a lot of diarrhea and cause your skin to turn a little yellow.

Niacin Supplements

A more common form of niacin is nicotinamide (NAM). It is also available without a prescription but less commonly found at your local pharmacy. Nicotinamide has all the same benefits of nicotinic acid but is less likely to cause flushing.

It can still cause a little redness and tingling, especially if you are sensitive to it. Take 1,000 mg of NAM once or twice daily. Like other B-complex vitamins, you will excrete any excess through your urine. Take NAM with food to reduce the chances of an upset stomach. You can also take NAM in a time-released formula to reduce the likelihood of an allergic reaction. Other forms of niacin include inositol nicotinate and nicotinamide riboside (NR).

Are There Any Potential Side Effects Or Interactions?

Nicotinic acid can cause your skin to become more sensitive to sunlight. Take a break from niacin supplements if you will be spending a lot of time outdoors. Avoid using other drugs that can make your skin more sensitive to sunlight as well, such as retinol (a form of vitamin A). Do not take niacin if you have liver disease.

Niacin is safe for most people when taken at the recommended daily dose. However, if you are allergic to niacin or any of the ingredients in the supplement, you should not take it. Do not take niacin if you are taking medication for diabetes or depression.

Be sure to tell your doctor if you are taking niacin so that he can monitor your liver health. Do not take more than is recommended. While there is no evidence that niacin causes heart disease, it can have a “toxic” effect on the liver if you take too much of it. The National Academy of Sciences does not set a tolerable upper limit for niacin at this time.

Sources & references used in this article:

The ABCs of Vitamins: Vitamin B3 (Niacin) by B Sly –

B vitamin acquisition by gut commensal bacteria by EE Putnam, AL Goodman – PLoS Pathogens, 2020 –

Diversity of membrane transport proteins for vitamins in bacteria and archaea by WDI Do