The Who, What, Where, When and Sometimes, Why.

Niacin

Niacin and Niacinamide Vitamin B3

What is it?

 

Niacin is a form of vitamin B3. It is found in foods such as yeast, meat, fish, milk, eggs, green vegetables, and cereal grains. Niacin is also produced in the body from tryptophan, which is found in protein-containing food. When taken as a supplement, niacin is often found in combination with other B vitamins.

Do not confuse niacin with niacinamide, inositol nicotinate, IP-6, or tryptophan. See the separate listings for these topics.

Niacin is commonly taken by mouth for high cholesterol and to increase levels of a specific type of good cholesterol, known as HDL. Niacin is also taken by mouth for preventing vitamin B3 deficiency and related conditions such as pellagra.

It is also taken by mouth for metabolic syndrome and diarrhea caused by cholera infection.

 

Natural Medicines 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.

The Effectiveness ratings for Niacin are as follows:

Likely Effective for…

  • Abnormal levels of blood fats. Some niacin products are approved by the U.S. Food and Drug Administration (FDA) as prescription products for treating abnormal levels of blood fats. These prescription niacin products typically come in high strengths of 500 mg or higher. Dietary supplement forms of niacin usually come in strengths of 250 mg or less. Since very high doses of niacin are required for improving cholesterol levels, dietary supplement niacin usually isn’t appropriate. For people who need to lower low-density lipoprotein (LDL or “bad”) cholesterol, the prescription drug class called “statins” is used. Niacin might be used in people with high levels of both cholesterol AND blood fats called triglycerides. Niacin may be combined with other cholesterol-lowering drugs when diet and single-drug therapy is not enough. Niacin improves cholesterol levels, but does not improve cardiovascular outcomes such as heart attacks and strokes.
  • Treatment and prevention of niacin deficiency, and certain conditions related to niacin deficiency such as pellagra. Niacin is approved by the U.S. Food and Drug Administration (FDA) for these uses. However, using niacinamide instead of niacin is sometimes preferred because niacinamide doesn’t cause “flushing,” (redness, itching and tingling), a side effect of niacin treatment.

Possibly Effective for…

  • Diarrhea from an infection called cholera. Taking niacin by mouth seems to control the loss of fluid due to cholera.
  • Abnormal levels of blood fats in people with HIV/AIDS. Taking niacin seems to improve levels of cholesterol and blood fats called triglycerides in HIV/AIDS patients with abnormal blood fat levels due to antiretroviral treatment.
  • Metabolic syndrome. Taking niacin 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. Taking the niacin along with a prescription omega-3 fatty acid seems to work even better.

Ineffective for…

  • Cardiovascular disease. High quality research shows that niacin does not prevent cardiovascular events such as a heart attack or stroke or death related to cardiovascular disease in people who take niacin to prevent or treat cardiovascular disease. Niacin has not been shown to reduce the risk of death. Niacin improves cholesterol levels, but it does not improve outcomes related to cardiovascular disease. Niacin should not be taken to treat or prevent cardiovascular disease.

Insufficient Evidence to Rate Effectiveness for…

  • Hardening of the arteries (atherosclerosis). Taking niacin by mouth along with medicines called bile acid sequestrants might reduce hardening of the arteries in men with this condition. It seems to work best in men with high levels of blood fats called triglycerides. But taking niacin does not seem to reduce hardening of the arteries in patients with a condition called peripheral arterial disease (PAD). Also, niacin does not prevent cardiovascular events such as a heart attack or stroke.
  • Alzheimer’s disease. People who consume higher amounts of niacin from food and multivitamins seem to have a lower risk of getting Alzheimer’s disease than people who consume less niacin. But there is no evidence that taking a stand-alone niacin supplement helps to prevent Alzheimer’s disease.
  • Cataracts. People who eat a diet high in niacin might have a reduced chance of developing nuclear cataracts. Nuclear cataract is the most common type of cataract. The effect of taking niacin supplementation is unknown.
  • Erectile dysfunction. Taking extended-release niacin 1.5 grams at bedtime for 12 weeks seems to help men with erectile dysfunction and high lipid levels maintain an erection during sexual intercourse.
  • Exercise performance. Research shows that taking a supplement containing niacin and other ingredients before exercise does not improve performance during exercise in men.
  • High levels of phosphate in the blood (hyperphosphatemia). High blood levels of phosphate can result from kidney dysfunction. Some early research shows that taking niacin by mouth can reduce blood levels of phosphate in people with end-stage kidney disease and high levels of blood phosphate. But other research shows that taking niacin by mouth at a higher dose does not lower blood phosphate levels when taken along with medication used to lower blood phosphate levels.
  • Blockage of the vein in the eye (retinal vein occlusion): Early research shows that taking niacin might improve eyesight in people with a blockage in the retinal vein.
  • Sickle cell disease: Early research shows that taking niacin does not improve the levels of blood fats in people with sickle cell disease.
  • Acne.
  • Alcohol dependence.
  • Attention deficit-hyperactivity disorder (ADHD).
  • Depression.
  • Dizziness.
  • Drug-induced hallucinations.
  • Migraine or premenstrual headache.
  • Motion sickness.
  • Schizophrenia.
  • Other conditions.

More evidence is needed to rate niacin for these uses.

Niacin is absorbed by the body when dissolved in water and taken by mouth. It is converted to niacinamide if taken in amounts greater than what is needed by the body.

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 beneficial effects on clotting. It may also improve levels of a certain type of fat called triglycerides in the blood.

Niacin deficiency can cause a condition called pellagra, which causes skin irritation, diarrhea, and dementia. Pellagra was common in the early twentieth century, but is less common now, since foods are now fortified with niacin. Pellagra has been virtually eliminated in western culture.

People with poor diet, alcoholism, and some types of slow-growing tumors called carcinoid tumors might be at risk for niacin deficiency.

Niacin is LIKELY SAFE for most people when taken by mouth. A common minor side effect of niacin is a flushing reaction. This might cause burning, tingling, itching, and redness of the face, arms, and chest, as well as headaches. Starting with small doses of niacin and taking 325 mg of aspirin before each dose of niacin will help reduce the flushing reaction. Usually, this reaction goes away as the body gets used to the medication. Alcohol can make the flushing reaction worse. Avoid large amounts of alcohol while taking niacin.

Other minor side effects of niacin are stomach upset, intestinal gas, dizziness, pain in the mouth, and other problems.

When doses of over 3 grams per day of niacin are taken, more serious side effects can happen. These include liver problems, gout, ulcers of the digestive tract, loss of vision, high blood sugar, irregular heartbeat, and other serious problems.

When used daily for multiple years, niacin might increase the risk of developing diabetes.

Some concern has been raised about stroke risk in people taking niacin. In one large study, people who took high doses of niacin had a two-fold greater risk of stroke compared to those not taking niacin. However, it is unclear if this outcome was due to niacin or some other unknown factor. Previous research has not identified any stroke risk related to taking niacin. Other research has shown that niacin has no effect on the risk of stroke.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Niacin is LIKELY SAFE for pregnant and breast-feeding women when taken in the recommended amounts. The recommended amount of niacin for pregnant or breast-feeding women is 30 mg per day for women under 18 years of age, and 35 mg for women over 18.

Allergies: Niacin can make allergies more severe because they cause histamine, the chemical responsible for allergic symptoms, to be released. .

Heart disease/unstable angina: Large amounts of niacin can increase the risk of irregular heartbeat. Use with caution.

Crohn’s disease: People with Crohn’s disease might have low niacin levels and require supplementation during flare-ups.

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 bring on gout.

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

Liver disease: Niacin might increase liver damage. Don’t use large amounts if you have liver disease.

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

Very low blood pressure: Niacin might lower blood pressure and worsen this condition.

Surgery: Niacin might interfere with blood sugar control during and after surgery. Stop taking niacin at least 2 weeks before a scheduled surgery.

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.

 

Alcohol (Ethanol)

Interaction Rating = Moderate Be cautious with this combination.
Talk with your health provider.

Niacin can cause flushing and itchiness. Consuming alcohol along with niacin might make the flushing and itching worse. There is also some concern that consuming alcohol with niacin might increase the chance of having liver damage.

Allopurinol (Zyloprim)

Interaction Rating = Moderate Be cautious with this combination.
Talk with your health provider.

Allopurinol (Zyloprim) is used to treat gout. Taking large doses of niacin might worsen gout and decrease the effectiveness of allopurinol (Zyloprim).

Aspirin

Interaction Rating = Minor Be watchful with this combination.
Talk with your health provider.

Aspirin is often used with niacin to reduce the flushing caused by niacin. Taking high doses of aspirin might decrease how fast the body gets rid of niacin. This could cause there to be too much niacin in the body and possibly lead to side effects. But the low doses of aspirin most commonly used for niacin-related flushing don’t seem to be a problem.

Clonidine (Catapres)

Interaction Rating = Moderate Be cautious with this combination.
Talk to your health provider.

Clonidine and niacin both lower blood pressure. Taking niacin with clonidine might cause your blood pressure to become too low.

Gemfibrozil (Lopid)

Taking niacin along with gemfibrozil might cause muscle damage in some people. Use with caution.

Medications for diabetes (Antidiabetes drugs)

Interaction Rating = Moderate Be cautious with this combination.
Talk with your health provider.

Long-term use of niacin and niacinamide might increase blood sugar. By increasing blood sugar, niacin and niacinamide might decrease the effectiveness of diabetes medications. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.

Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), metformin (Glucophage), nateglinide (Starlix), repaglinide (Prandin), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.

Medications for high blood pressure (Antihypertensive drugs)

Interaction Rating = Moderate Be cautious with this combination.
Talk to your health provider.

Using niacin with drugs that lower blood pressure may increase the effects of these drugs and may lower blood pressure too much.

Some medications for high blood pressure include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), amlodipine (Norvasc), hydrochlorothiazide (HydroDIURIL), furosemide (Lasix), and many others.

Medications that can harm the liver (Hepatotoxic drugs)

Interaction Rating = Moderate Be cautious with this combination.
Talk to your health provider.

Niacin might harm the liver. Sustained-release niacin preparations seem to have the greatest risk. Taking niacin along with medication that might also harm the liver can increase the risk of liver damage. Do not take niacin if you are taking a medication that can harm the liver.

Some medications that can harm the liver include acetaminophen (Tylenol and others), amiodarone (Cordarone), carbamazepine (Tegretol), isoniazid (INH), methotrexate (Rheumatrex), methyldopa (Aldomet), fluconazole (Diflucan), itraconazole (Sporanox), erythromycin (Erythrocin, Ilosone, others), phenytoin (Dilantin), lovastatin (Mevacor), pravastatin (Pravachol), simvastatin (Zocor), and many others.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)

Interaction Rating = Moderate Be cautious with this combination.
Talk to your health provider.

Niacin might slow blood clotting. Taking niacin along with medications that also slow clotting might increase the chances of bruising and bleeding.

Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, indomethacin (Indocin), ticlopidine (Ticlid), warfarin (Coumadin), and others.

Medications used for lowering cholesterol (Bile acid sequestrants)

Interaction Rating = Moderate Be cautious with this combination.
Talk to your health provider.

Some medications for lowering cholesterol called bile acid sequestrants can decrease how much niacin the body absorbs. This might reduce the effectiveness of niacin. Take niacin and the medications at least 4-6 hours apart.

Some of these medications used for lowering cholesterol include cholestyramine (Questran) and colestipol (Colestid).

Medications used for lowering cholesterol (Statins)

Interaction Rating = Moderate Be cautious with this combination.
Talk to your health provider.

Niacin can adversely affect the muscles. Some medications used for lowering cholesterol called statins can also affect the muscles. Taking niacin along with these medications might increase the risk of muscle problems.

Some of these medications used for high cholesterol include rosuvastatin (Crestor), atorvastatin (Lipitor), lovastatin (Mevacor), pravastatin (Pravachol), fluvastatin (Lescol), and simvastatin (Zocor).

Nicotine patch (Transdermal nicotine)

Interaction Rating = Minor Be watchful with this combination.
Talk to your health provider.

Niacin can sometimes cause flushing and dizziness. The nicotine patch can also cause flushing and dizziness. Taking niacin or niacinamide and using a nicotine patch can increase the possibility of becoming flushed and dizzy.

Probenecid

Interaction Rating = Moderate Be cautious with this combination.
Talk to your health provider.

Probenecid is used to treat gout. Taking large doses of niacin might worsen gout and decrease the effectiveness of probenecid.

Sulfinpyrazone (Anturane)

Interaction Rating = Moderate Be cautious with this combination.
Talk with your health provider.

Sulfinpyrazone (Anturane) is used to treat gout. Taking large doses of niacin might worsen gout and decrease the effectiveness of sulfinpyrazone (Anturane).

Thyroid hormone

Interaction Rating = Moderate Be cautious with this combination.
Talk to your health provider.

Sulfinpyrazone (Anturane) is used to treat gout. Taking large doses of niacin might worsen gout and decrease the effectiveness of sulfinpyrazone (Anturane).

Beta-carotene

A combination of niacin and the prescription drug simvastatin (Zocor) raises HDL (high density lipoprotein) cholesterol (“good cholesterol”) in people with coronary heart disease and low HDL levels. However, taking niacin along with combinations of antioxidants, including beta-carotene, seems to blunt this rise in HDL. It is not known whether this effect happens in people who don’t have coronary heart disease.

Chromium

Taking niacin and chromium together might lower blood sugar. If you have diabetes and take chromium and niacin supplements together, monitor your blood sugar to make sure it doesn’t get too low.

Herbs and supplements that lower blood pressure (hypotensive herbs and supplements)

Niacin might lower blood pressure. Taking niacin with other herbs and supplements that also lower blood pressure might cause blood pressure to drop too much. Other herbs and supplements that can lower blood pressure include andrographis, casein peptides, cat’s claw, coenzyme Q10, L-arginine, lycium, stinging nettle, theanine, and others.

Herbs and supplements that might harm the liver

Niacin, especially in higher doses can cause liver damage. Taking niacin along with other herbs or supplements that might harm the liver could increase this risk. Some of these products include androstenedione, borage leaf, chaparral, comfrey, dehydroepiandrosterone (DHEA), germander, kava, pennyroyal oil, red yeast, and others.

Herbs and supplements that might slow blood clotting

Niacin might slow blood clotting. Using niacin along with other herbs and supplements that also slow blood clotting might increase the risk of bleeding in some people. Some other herbs of this type include angelica, clove, danshen, garlic, ginger, Panax ginseng, and others.

Kombucha tea

There is some concern that kombucha tea might decrease niacin absorption. But this needs to be studied more.

Selenium

A combination of niacin and the prescription drug simvastatin (Zocor) raises HDL (high density lipoprotein) cholesterol (“good cholesterol”) in people with coronary heart disease and low HDL levels. However, taking niacin along with combinations of antioxidants, including selenium, seems to blunt this rise in HDL. It is not known whether this effect happens in people who don’t have coronary heart disease.

Tryptophan

Some tryptophan from the diet can be converted into niacin in the body. Taking niacin and tryptophan together might increase levels and side effects of niacin.

Vitamin C

A combination of niacin and the prescription drug simvastatin (Zocor) raises HDL (high density lipoprotein) cholesterol (“good cholesterol”) in people with coronary heart disease and low HDL levels. However, taking niacin along with combinations of antioxidants, including vitamin C, seems to blunt this rise in HDL. It is not known whether this effect happens in people who don’t have coronary heart disease.

Vitamin E

A combination of niacin and the prescription drug simvastatin (Zocor) raises HDL (high density lipoprotein) cholesterol (“good cholesterol”) in people with coronary heart disease and low HDL levels. However, taking niacin along with combinations of antioxidants, including vitamin E, seems to blunt this rise in HDL. It is not known whether this effect happens in people who don’t have coronary heart disease.

Zinc

The body can make niacin. People who are malnourished and have niacin deficiency, such as chronic alcoholics, make extra niacin if they take zinc. There might be an increased risk of niacin-related side effects such as flushing and itching if niacin and zinc are taken together.

Hot drinks

Niacin can cause flushing and itching. These effects might be increased if niacin is taken with a hot drink.

The following doses have been studied in scientific research:

ADULTS

BY MOUTH:

  • For high cholesterol: The effects of niacin are dose-dependent. The biggest increases in HDL and decreases in triglycerides occur at 1200-1500 mg/day. Niacin’s greatest effects on LDL occur at 2000-3000 mg/day.
  • To prevent heart disease in people with high cholesterol: Niacin 4 grams daily.
  • For preventing and treating vitamin B3 deficiency and related conditions such as pellagra: 300-1000 mg daily in divided doses.
  • For treating hardening of the arteries: 1000-4200 mg of niacin daily, alone or along with statins or bile acid sequestrants, has been used for up to 6.2 years.
  • For reducing fluid loss caused by cholera toxin: Niacin 2 grams daily.
  • For abnormal blood fat levels due to treatment for HIV/AIDS:

BY IV:

  • High cholesterol: 2 grams of niacin administered intravenously over an 11-hour time period at night.
  • For preventing and treating vitamin B3 deficiency and related conditions such as pellagra: 60 mg of niacin has been used.

AS A SHOT:

  • For preventing and treating vitamin B3 deficiency and related conditions such as pellagra: 60 mg of niacin has been used.

CHILDREN

BY MOUTH:

  • For preventing and treating vitamin B3 deficiency and related conditions such as pellagra: 100-300 mg per day of niacin, given in divided doses.

The daily recommended dietary allowances (RDAs) of niacin are: Infants 0-6 months, 2 mg; Infants 7-12 months, 4 mg; Children 1-3 years, 6 mg; Children 4-8 years, 8 mg; Children 9-13 years, 12 mg; Men 14 years and older, 16 mg; Women 14 years and older, 14 mg; Pregnant women, 18 mg; and Lactating women, 17 mg. The maximum daily dose of niacin is: Children 1-3 years, 10 mg; Children 4-8 years, 15 mg; Children 9-13 years, 20 mg; Adults, including Pregnant and Lactating women, 14-18 years, 30 mg; and Adults, including pregnant and breast-feeding women, older than 18 years, 35 mg.

 

3-Pyridinecarboxylic Acid, Acide Nicotinique, Acide Pyridine-Carboxylique-3, Anti-Blacktongue Factor, Antipellagra Factor, B Complex Vitamin, Complexe de Vitamines B, Facteur Anti-Pellagre, Niacina, Niacine, Nicotinic Acid, Pellagra Preventing Factor, Vitamin B3, Vitamin PP, Vitamina B3, Vitamine B3, Vitamine PP.


 

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