Niacin

What is it?

Niacin is a form of vitamin B3 made in the body from tryptophan. It’s found in many foods including meat, fish, milk, eggs, green vegetables, and cereals.

Niacin is required for the proper function of fats and sugars in the body and to maintain healthy cells. At high doses, niacin might help people with heart disease because of its effects on blood clotting. It might also improve levels of fats called triglycerides in the blood.

Prescription forms of niacin are approved by the US FDA for abnormal cholesterol levels and for preventing vitamin B3 deficiency and related conditions such as pellagra. People use niacin supplements for metabolic syndrome, heart disease, cataracts, high blood pressure, and many other conditions, but there is no good scientific evidence to support most of these other uses.

Do not confuse niacin with NADH, niacinamide, inositol nicotinate, IP-6, or tryptophan. These are not the same.

Is it effective?

NatMed Pro rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

Probably Effective for …

Abnormal levels of cholesterol or blood fats (dyslipidemia). Taking niacin prescription products by mouth in doses of 500 mg or more improves cholesterol levels in people with abnormal cholesterol. Dietary supplement forms of niacin usually come in lower doses and don’t seem to improve blood fat levels.
A disease caused by niacin deficiency (pellagra). Niacin prescription products are US FDA approved for preventing and treating pellagra.

Possibly Effective for …

Abnormal levels of blood fats in people with HIV/AIDS. Taking prescription niacin products by mouth seems to improve levels of cholesterol and blood fats called triglycerides in people with this condition. It is unclear if niacin supplements are helpful.
A grouping of symptoms that increase the risk of diabetes, heart disease, and stroke (metabolic syndrome). Taking prescription niacin products by mouth seems to increase levels of high-density lipoprotein (HDL or “good”) cholesterol and reduce levels of blood fats called triglycerides in people with metabolic syndrome. It is unclear if niacin supplements are helpful.

Ineffective for …

Heart disease. Taking niacin by mouth does not prevent heart attack or stroke in people with or without heart disease.

There is interest in using niacin for a number of other purposes, but there isn’t enough reliable information to say whether it might be helpful.

Is there concern for the safety of its use?

When taken by mouth: Niacin is likely safe for most people when used appropriately. Prescription products containing niacin are safe when taken as directed. Niacin-containing foods or niacin supplements are safe when taken in doses lower than 35 mg daily.

A common side effect of niacin is a flushing reaction. This might cause burning, itching, and redness of the face, arms, and chest, as well as headaches. Starting with small doses and taking 325 mg of aspirin before each dose of niacin may help. This reaction usually goes away as the body gets used to niacin.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Niacin is likely safe when taken by mouth while pregnant and breast-feeding. The maximum recommended amount of niacin while pregnant or breast-feeding is 30 mg daily in those under 18 years of age, and 35 mg daily for those 19 years and older.

Children: Niacin is likely safe when taken by mouth in doses below the tolerable upper intake level (UL) by age. The UL is 10 mg for children 1-3 years of age, 15 mg for children 4-8 years of age, 20 mg for children 9-13 years of age, and 30 mg for children 14-18 years of age.

Allergies: Niacin might worsen allergies by causing histamine to be released. Histamine is the chemical responsible for allergic symptoms.

Chest pain (angina): Niacin should be used cautiously in people with angina.

Diabetes: Niacin might increase blood sugar. People with diabetes who take niacin should check their blood sugar carefully.

Gallbladder disease: Niacin might make gallbladder disease worse.

Gout: Large amounts of niacin might increase the risk for gout.

Kidney disease: Niacin might accumulate in people with kidney disease. This might cause harm.

Liver disease: Taking high doses of niacin might increase liver damage. Don’t use large amounts if you have liver disease.

Low blood pressure: Taking niacin in high doses might lower blood pressure and worsen this condition.

Stomach or intestinal ulcers: Niacin might make ulcers worse. Don’t use large amounts if you have ulcers.

Surgery: Niacin might interfere with blood sugar control during and after surgery. Speak with your healthcare provider about whether you should stop taking niacin before a scheduled surgery.

Fatty deposits around tendons (tendon xanthomas): Niacin might increase the risk of infections in xanthomas.

Thyroid disorders: Thyroxine is a hormone produced by the thyroid gland. Niacin might lower blood levels of thyroxine. This might worsen symptoms of certain thyroid disorders.