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Niacin Benefits, Side Effects & Safety Information

Published: 13th May 2018. Last updated: 21th July 2019.

Shaun Ward MSc ANutr

Staff Writer


Niacin is one of the many water-soluble B vitamins, also known as vitamin B3 or nicotinic acid.

When niacin is absorbed, it is converted in the body to its metabolically active form; coenzyme nicotinamide adenine dinucleotide (NAD).

NAD is required by most cells within the body for energy production, as it is directly involved in transferring the potential energy in macronutrients (proteins, fat, carbohydrates) into ATP - the cell’s primary energy currency.

In addition, NAD is required by enzymes involved in metabolic activities such as the maintenance of the genome (DNA and genes) and communication between cells.

Therefore, although niacin is predominantly known for health benefits such as disease prevention, it is also a fundamental contributor to these essential metabolic needs.

The recommended daily amount for adult males if 16mg per day, and for females is 14mg per day.

During pregnancy this is increased to 18mg per day, and when lactating niacin intake should still to be raised to 17mg per day.

The Potential Benefits of Niacin

Below is a list of the main benefits that have credible scientific backing:

It May Improve Cholesterol Profiles

Niacin is effective at lowering cholesterol and is an extremely common prescription medication for this reason.

Studies show that high niacin intake can increase HDL (“good”) levels by up to ~25% [1].

When compared to powerful statins, which can increase HDL levels by only 5-15%, it is clear how much niacin influences lipid profiles [2].

Niacin has also shown to have other beneficial effects on lipid profiles, such as lowering LDL (“bad”) cholesterol levels by 10-25%, and triglyceride levels by 20-50% [3].

However, for niacin to have these effects on cholesterol levels, extremely high doses need to be taken (up to 100 times the recommended amounts) at which point the benefits do not outweigh the potential harms of their adverse effects.

It May Reduce Heart Disease Risk

Given that it only takes a 1mg/dl increase in HDL levels to reduce cardiovascular disease rates by 2-3%, niacin consumption in clinical doses can have positive effects on this disease [4].

Niacin supplementation, alongside statins, has also caused significant decreases in atherosclerosis, leading to a 90% decrease in coronary heart disease [5].

However, despite this evidence, many experts do not agree that niacin alone can effectively treat cardiovascular disease, especially when the potential side effects and safety concerns are accounted for [6].

This is primarily based on a recent review which concluded that niacin supplementation alone provides little, if any, protection from atherosclerotic heart disease, despite improvements to HDL and LDL levels [7].

More research is necessary to analyze the relationship better, as theoretically, niacin should be preventing cardiovascular disease based on its effects to increasing HDL levels, and reducing LDL levels, both of which are independently associated with cardioprotective properties [8].

It May Boost Brain Function

Your brain needs niacin to produce energy and function properly, as niacin is a precursor for the coenzyme NAD – needed for cellular respiration processes of all living cells.

Based on this, it is not surprising that niacin deficiency is commonly linked to brain fog and even psychiatric symptoms [9].

There are even cases where schizophrenia has been effectively treated with niacin, as it helps restore the damage to brain cells that occurred as a result of niacin deficiency [10].

Research has also suggested that niacin may help to maintain cognitive function during periods of rapid decline, such as in Alzheimer's disease [11] [12].

It May Protect Against DNA Damage

Animal studies have shown an increased rate of DNA repair when niacin levels are meeting recommended amounts [13].

Limited evidence also suggests that niacin can alter cell activity and stabilize genes, preventing them from mutation that may cause various diseases [14].

This is especially important for cancer prevention, which can be formed from DNA damage when cell activity is sporadic.

Future research may clarify more detail on niacin’s relationship with cancer.

What Foods Contain Niacin?

Niacin can be found in a wide range of food groups including plant and animal-based sources.

The best sources of niacin are (per 100 grams):

  • Yellowfin tuna: 138% of the recommended daily intake
  • Dry roasted peanuts: 90% of the recommended daily intake
  • Lean chicken breast: 59% of the recommended daily intake
  • Lean pork chops: 50% of the recommended daily intake
  • Portabella mushrooms: 39% of the recommended daily intake
  • Beef: 35% of the recommended daily intake
  • Brown rice: 16% of the recommended daily intake

Other plant-based sources are sunflower seeds, espresso, soybeans, potatoes, enoki, all bran, peas, lentils, pasta, grains and falafel.

Other animal-based sources are mackerel, salmon, chicken, turkey, and lamb.

In terms of the variation in bioavailability between food sources, no data suggests concerns for any significant differences, with all foods generally having a high bioavailability of above ~80%.

The only exception to this are some grain products, as niacin will be bound to polysaccharides and glycopeptides that massively reduce the bioavailability to ~30% [15].

Supplemental niacin, including enriched and fortified foods, are also highly bioavailable forms of niacin and can be included within the diet if needed.

Niacin Deficiency

In developed countries, niacin deficiency is rare and is typically only found in alcoholics. It is estimated that only 1% of adults have niacin intakes below the recommended daily amount [16].

The most common symptoms of niacin deficiency are fatigue, indigestion, vomiting, poor circulation and depression.

However, niacin deficiency may only be noticed when levels are severely low and symptoms of Pellagra are apparent; dementia, diarrhea, and dermatitis. Although deficiency is rare, Pellagra left untreated has the potential to be fatal by significantly affecting the digestive and nervous system.

Digestive issues are usually indicated by inflammation of the mouth, or if one notices constipation.

Problems with the nervous system are typically noticed by increased fatigue, extreme headaches, or regular cases of memory loss.

If you notice any of these symptoms it is important to report them to your General Practitioner as soon as possible.

Safety and Side Effects Information

As mentioned, the vast majority of people can reach the daily recommended amount of niacin from food, provided their diet has at least some appreciable amount of whole unprocessed food sources [17].

Partly due to this, additional niacin intake from supplementation may lead to an overconsumption of niacin, and lead to long list of side effects including:

  • Liver damage
  • Nausea
  • Blurred Vision
  • Hot flushes
  • Impaired blood sugar control
  • Gout

When taken in pharmacologic doses of 1,000-3,000 mg/day, more serious adverse effects are found such as:

  • Hypotension
  • Impaired glucose tolerance
  • Insulin resistance
  • Heartburn
  • Fluid build-up within eyes

Due to its impact on the liver, it has also been documented that niacin can interact with several medications including:

  • Antibiotics
  • Aspirin
  • Anti-seizure medications
  • Anticoagulants (blood thinners)
  • Blood pressure medications (alpha-blockers)
  • Cholesterol-lowering medications
  • Statins
  • Diabetes medications
  • Nicotine patches

If you are currently taking medications, or regularly drink alcohol, you should not use niacin without talking to your health care provider first.


Niacin is one of the many water-soluble B vitamins that is converted in the body to its metabolically active form; coenzyme nicotinamide adenine dinucleotide (NAD).

NAD is required by most cells within the body for energy production, and is involved in other metabolic activities such as the maintenance of the genome (DNA and genes) and communication between cells.

Niacin, especially in high doses, can significantly reduce cholesterol levels. However, this has not consistently shown to prevent against heart disease.

Other benefits may be improved brain function and increased protection against DNA damage.

Most people consume enough niacin from the diet, and therefore it is not an essential supplement to consume unless a niacin deficiency has been clinically diagnosed.

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