Vitamin B3

What is Vitamin B3?

Vitamin B3 comes in two different forms known as Niacin (Nicotinic Acid) and Niacinamide (Nicotinamide). Vitamin B3 is one of the 8 B vitamins which makes up the B complex family. It is also a part of the Vitamin B3 complex which also includes nicotinamide (niacinamide) and nicotinamide riboside. Vitamin B3 is water-soluble which means your body does not store it and can be excreted through urine.

Vitamin B3 is a white crystalline powder and unlike certain other B vitamins such as Riboflavin it will not turn the urine into a yellow-orange color. Vitamin B3 / niacin is found in the liver and skeletal muscle and is the most stable of all water-soluble vitamins.

Niacin (Nicotinic acid) and Niacinamide (Nicotinamide) are both the vitamin forms of Niacin. The body can obtain and synthesize both forms of Vitamin B3 from the diet although nicotinamide is more common.

Niacin and Niacinamide can be synthesized from the amino acid tryptophan in the liver however this production is not enough especially in the case of a deficiency. The body's nutritional status effects the efficiency of synthesizing niacin as other vitamins and minerals are required as well as energy for the process. Some of these vitamins and minerals include iron, riboflavin, Vitamin B6 (PLP), also need trp and adequate energy. These nutrients are required for the conversion of tryptophan to NAD+.  Only about 3% of the body's tryptophan is used to make niacin. Approximately 60 mg of tryptophan is used to make 1 mg of niacin.

Digestion and absorption of vitamin B3

Most of the niacin are absorbed in the small intestines.

One of the major function of niacin is to make the coenzymes Nicotinamide adenine dinucleotide (NAD) and Nicotinamide adenine dinucleotide phosphate (NADP). Most of the conversion is done in the liver. The most common form found in food is NAD enzyme.  NAD and NADP are hydrolyzed in the intestine to nicotinamide. The common form of niacin found in enriched or fortified foods is vitamin form Nicotinamide. Both coenzyme forms can be formed from tryptophan.

Niacin is essential in the diet and required for energy production, brain function, to maintain healthy skin and has many other health benefits.

Health Benefits of Vitamin B3 (Niacin and Niacinamide)

Niacin is used in more than 50 different chemical reactions within the body and has numerous health benefits which includes balancing blood sugar levels and lower cholesterol levels.

Niacin helps lower bad cholesterol (LDL) and increase good cholesterol (HDL)

Niacin is used in the treatment of Hypercholesterolemia (high blood cholesterol) as nicotinic acid. Pharmacological large doses of niacin have been shown to lower total serum cholesterol, lower LDL cholesterol and increase HDL in some individuals. It can also help prevent the accumulation of plaque in the arteries (atherosclerosis). Niacin may also reduce the risk of a second heart attack in those with high cholesterol levels although more studies need to be done to provide sufficient evidence. It is the niacin form that is beneficial for lowering bad levels of cholesterol.

Niacin is preferred form of vitamin B3 for lowering high cholesterol levels.

Niacin is particularly associated with lowering high cholesterol levels which can help prevent the hardening of arteries or arteriosclerosis. This effect has a great benefit for cardiac health as the risk for heart attacks is associated with high cholesterol levels that lead to hardening of the arteries.

Niacinamide does not have the same cholesterol lowering benefits as niacin. Niacinmaide is derived from niacin which does not include the cholesterol lowering effects of niacin.

Niacin is needed for energy metabolism

Niacin is needed for protein, fats and carbohydrate metabolism. It helps to metabolize carbohydrates into glucose, which your cells use for energy. Niacin also plays an important role in the synthesis and repair of DNA.

Niacin maintains healthy skin and hair

A regular intake of niacin can help to keep our hair and skin healthy and prevent aging skin. Niacin can help prevent dermatitis issues such as skin blisters, pimples and acne. Regular consumption of niacinamide, a form of vitamin B3 helps with balancing moisture in the skin preventing dryness.

A severe deficiency symptom is visible in people with pellagra, a condition masked by dermatitis which indicates that a niacin sufficiency can maintain and strengthen the health of your skin.

Niacin can help maintain blood sugar levels and prevent diabetes

Niacin helps your body use insulin efficiently which can help to control blood sugar levels. This is beneficial for those who suffer an imbalance of blood sugar levels however some studies are now showing that niacin may be dangerous for those with type 2 diabetes and has also revealed that in people with these condition niacin may increase blood sugar level. It may however be helpful in people with type 1 diabetes as there is a chemical substance niacinamide if taken regularly may delay the requirement of insulin. It is excellent when used in treating early diabetes however it is not recommended to use for advanced cases.

It’s important to note that in the case of those with diabetes it is best to speak to a medical professional before taking large doses. It is also best to use a blood sugar monitor to keep your blood sugar levels in check and see how niacin may be effecting you.

Niacin improves blood circulation

Niacin has vasodilation effects which dilates blood vessels facilitating blood circulation increasing blood flow to skin and extremities. This will help improve overall circulation and oxygenate the body.

The effect of this can be directly felt and is known as niacin flush. Niacin also helps maintain normal blood pressure levels and can help keep blood triglyceride amounts balanced. Niacin is the effective form of vitamin B3 in improving blood circulation.

The form of vitamin B3 preferred for treating circulatory problems is Niacin.

Niacin benefits the nervous system

Your nervous system and brain need niacin to function. Niacin can help maintain and strengthen the nervous system. Central nervous system neural degeneration has been linked to niacin deficiency. [1]

Niacin benefits the digestive system

Niacin maintains and strengthens gastro-intestinal tract and can help improve the health of the digestive tract.

Niacin helps with hormone synthesis

Niacin helps the body produce many hormones supporting healthy levels of male and female sex hormones. In addition to the sex hormones niacin can also help the body make stress-related hormones in the adrenal glands and other parts of the body.

Niacin for mental health problems

Niacin significantly reduce anxiety and depression aiding good sleep and induce relaxation naturally. It has also been shown that those who suffer from schizophrenia and experience other psychiatric symptoms have a niacin deficiency which indicates that taking niacin supplements may help reduce these psychiatric conditions. Both forms of Vitamin B3, Niacin and Niacinamide can be used in treating physical and emotional stress. Vitamin B3 as niacin or niacinamide may be used for relieving symptoms associated with depression and anxiety. It is recommended by doctors to take either forms of Vitamin B3 in combination with Vitamin B1, B2 and C for Vitamin B3 to be effective. [2] [3]

Niacin for Osteoarthritis and Arthritis

Niacin has antioxidant mechanisms protecting the body against inflammatory diseases. Many of the diseases listed above such as Alzheimer’s, diabetes and hyperlipidemia are inflammatory diseases. It has been shown to reduce early-onset arthritis. In one study niacinamide has shown to reduce symptoms and improve joint flexibility in patients suffering from osteoarthritis. [4]. Niacinamide is the preferred form for treating inflammatory diseases such as osteoarthritis and diabetes.

Niacin for Alzheimer’s

Niacin is also beneficial for improving memory of those with Alzheimer’s in combination with other B vitamins that help with memory functions.

Agonist / Synergist (Works well with)

Vitamins: A, B1, B2, B5, B6, B9, B10, B12, C, E

Minerals: Cr, Cu, Fe, K, Mg, Mn, P, Na, Se, Zn

Antagonist (Inhibits absorption or decreases levels)

Vitamins: A

Minerals: Ca, Cu, Na

Antibiotics, tea, coffee, birth control pill, alcohol

Food Sources of Vitamin B3

Niacin can be found in Protein rich foods and whole grains as well as grains that have been enriched or fortified.

Main sources of niacin include mushrooms, tuna, chicken, salmon, asparagus, cabbage, lamb, mackerel, turkey, eggs, tomatoes, courgettes, squash, cauliflower, milk and wholewheat.

The amounts recommended for vitamins and minerals are different for each country which can be found on the government website of host country. The nutritional data for each country are based on scientific research which are presented by the scientific academies in each country to help advise governmental departments for food and human nutrition.

Below is a list of some of the countries and the EU for which nutritional guidelines are available found on corresponding official government website (including the national academy of science website for the USA).


The  2015–2020 Dietary Guidelines for Americans -  Dietary Reference Intakes

Recommended Dietary Allowances and Adequate Intakes from Food and Nutrition Board, Institute of Medicine, National Academies

Dietary Reference Intakes (DRIs) Food and Nutrition Board, Institute of Medicine, National Academies

Dietary Reference Intakes (DRIs): Tolerable Upper Intake Levels (UL)


Dietary Reference Intakes includes Tolerable Upper Intake Levels


Nutrition Requirements

Safe Upper Levels (SULs) for Vitamins and Minerals

Australia and New Zealand

Nutrient Reference Values (NRVs) and Upper Level Intake 


Dietary Reference Values for nutrients

Tolerable Upper Intake Levels For Vitamins and Minerals

Vitamin B3 Supplementation

Niacin is a white crystalline powder and is available as niacin which causes flushing and the non-flushing known as niacinamide.

There are two forms of Vitamin B3 available to purchase for supplementation. It is important to note that both have different effects and different functions as well as side effects.

Niacin form of Vitamin B3

Niacin is the form of vitamin B3 that is the preferred treatment for the following effects:

  • Lowering high cholesterol levels
  • Improving blood circulation
  • Improve nervous system
  • Improve digestion system
  • Treating physical and emotional stress
  • Improve mental health problems such as anxiety and depression

Niacin can also be more effective than niacinamide in most cases as the body is able to convert niacin into niacinamide.

Time release niacin is a type of supplement form of vitamin B3 which releases slowly to avoid the side effects of niacin associated with flushing. Long term use of time release niacin should be avoided as it has been shown to contribute to liver damage.

Niacinamide form of Vitamin B3

Niacinamide is the form of vitamin B3 that is the preferred treatment for the following effects:

  • Improving the health of skin – niacinamide is also the preferred form for pellagra
  • Treating physical and emotional stress
  • Improve mental health problems such as anxiety and depression
  • Inflammatory diseases such as osteoarthritis, diabetes and Alzheimer’s

Both forms of Vitamin B3, Niacin and Niacinamide can be used in treating physical and emotional stress. Niacin or niacinamide can be used for treating anxiety and depression. It is recommended by doctors to take either forms of Vitamin B3 in combination with Vitamin B1, B2 and C for Vitamin B3 to be effective.

Deficiency Symptoms of Vitamin B3

There are various signs of niacin deficiency. Insufficient niacin in the diet can cause:

  • Tiredness or chronic fatigue
  • Diarrhea
  • Insomnia
  • Nausea
  • Headaches or migraines
  • Muscle weakness
  • Muscle pain
  • Dementia
  • Poor memory
  • Confusion
  • Anemia
  • Anxiety
  • Tension
  • Depression
  • Irritability
  • Skin and mouth lesions
  • Bleeding or tender gums
  • Acne
  • Eczema/dermatitis
  • Pellagra (also known as angry skin)
  • Sunlight sensitivity

Very severe cases of niacin deficiency can also cause death.

Severe niacin deficiency signs include Pellagra. An outbreak of Pellagra occurred where maize was a commonly consumed food crop. Pelle means skin, agra means sour which is how the diseases was named. Pellagra is also. Pellagra is also common with those with HIV or AIDS as people with this condition are also at risk of a niacin deficiency. [5]

Niacin in foods can be covalently bound to some proteins and carbohydrates, making it unavailable. When niacin is bound to carbs it is known as niacytin and when bound to proteins it is known as niacinogen. Niacin has been shown to bind mostly to corn which is also a very poor source of tryptophan which is used to make niacin and only about 10% of niacin available for absorption in corn. This may be one of the major reasons for the Pellagra outbreak as corn is a staple food in some countries.

*Dermatitis - abnormities or inflammation of the skin which may produce a dark, red rash in areas exposed to the sun (Casal's Necklace).

Dementia which can produce a state of delirium or mental confusion has also been linked to niacin deficiency and having enough niacin in the body may provide a protection again Alzheimer’s Disease. [6].

Toxicity Symptoms of Vitamin B3

Although there are no known toxicity below 3,000mg taking the different forms of Vitamin B3 can produce some side effects.

Niacin Flush

Vasodilatory effects of niacin which is known as a “Niacin Flush” is common when taking Niacin supplements. Niacin has the effect of causing blood vessels to widen increasing more blood flow which can cause various symptoms felt on the skin such as itchy or skin color turning red. This is a good indicator that you are taking more than needed. This only happens if too much is taken in one dose. If taking higher doses it is best to separate doses. It is better to titrate dosage so that you are starting with a small amount, each day increasing the dosage. If a Niacin flush starts it is good to lower the dose and remain on this amount. Niacinamide is the non-flushing type which will not cause flushing.

Some of the symptoms of a niacin flush include:

  • Tingling, burning or itching sensation
  • Warm skin which may be beneficial for cold hands and feet
  • Reddening of skin – this can range from mild red to a sunburn shade of red

It is impossible to get toxicity symptoms of Niacin from food as there are negligible amounts. It is however more likely to get toxicity symptoms from taking too much Niacin supplements or drugs.

The following are signs and symptoms of niacin overdose:

  • Diarrhea
  • Fainting
  • Painful rash
  • Sweating
  • Abnormal liver function
  • Niacin flush with dizziness
  • Rapid heartbeat
  • Itching
  • Nausea
  • Vomiting
  • Abdominal pain
  • Gout

Niacinamide is preferred when using vitamin B3 as a treatment for pellagra as it is non-flushing and treatment requires high doses of vitamin B3. Niacinamide has very fewer side effects and may only cause excessive sweating. An overdose of niacinamide can lead to liver toxicity. Time release version of niacin is designed to reduce the niacin flushing effects however long term use has been associated liver damage.

Precautions and Warnings

Using niacin for lowering cholesterol will have various side effects.

Niacin during pregnancy are generally considered safe, however there are insufficient studies or information on high doses of niacin during pregnancy.