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Vitamin B3 (Niacin)

Niacin is an essential B-vitamin. Supplementation results in improved cholesterol and triglyceride levels. However, since a side-effect of supplementation is increased insulin resistance, niacin supplementation only provides benefits for cardiovascular health if precautions are taken.

Our evidence-based analysis on vitamin b3 (niacin) features 277 unique references to scientific papers.

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Summary of Vitamin B3 (Niacin)

Primary information, health benefits, side effects, usage, and other important details

Vitamin B3 refers to the molecule commonly called nicotinic acid, or niacin, though it may also refer to the other vitamin B3 vitamer, called nicotinamide. Vitamin B3 is necessary to support the function of many enzymes.

Niacin supplementation is very effective at normalizing blood lipid levels. People with low HDL-C levels supplementation experience an increase in HDL-C levels, while people with high LDL-C experience a reduction in LDL-C levels. Triglyceride levels also fall after supplementation, which makes niacin look like a great cardioprotective supplement on paper. Unfortunately, niacin supplementation does not result in reduced cardiovascular disease risk, since it also increases insulin resistance, which negates the benefits niacin provides for blood lipid levels.

Other benefits of niacin supplementation are theorized to extend to growth, cognition, and longevity. This is because niacin supplementation increases cellular nicotinamide adenine dinucleotide (NAD+) levels. Preliminary evidence suggests increased NAD+ levels may result in the above benefits, but much more research is needed to determine if this effect actually occurs. Topical application of nicotinamide is sometimes used for skin health, though it is not as effective as vitamin A. Nicotinamide is used for topical application because it does not result in the flushed skin that niacin supplementation can cause.

Current evidence suggests prolonged niacin supplementation increases insulin resistance because it hinders the ability of insulin to suppress glucose synthesis in the liver. This causes an increase in blood glucose levels, which leads to lowered insulin sensitivity over time, since the relevant receptor is eventually desensitized to the elevated glucose levels in the blood. The flush caused by niacin supplementation is a temporary effect. Though it may be uncomfortable, it is not harmful. There are many case studies describing people overdosing on niacin in an effort to pass a urine test. Niacin overdose results in multiple organ failure and is not effective at masking a urine test.

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How to Take

Recommended dosage, active amounts, other details

Most of the benefits from niacin supplementation occur after doses of at least one gram. This is approximately 5,000% the recommended daily intake.

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Human Effect Matrix

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The Human Effect Matrix summarizes human studies to tell you what effects Vitamin B3 (Niacin) has on your body, how much evidence there is, and how strong these effects are.

Full details are available to Examine members.
Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
grade-b Strong Very High See all 6 studies
Niacin supplementation is currently the major reference for increasing HDL cholesterol concentrations rapidly and reliably, at times being called the Golden Standard for HDL increasing pharmaceuticals.
grade-b Notable Very High See all 3 studies
Topical application of 4% nicotinamide gel rivals 1% clindamycin gel in reducing acne severity and tends to work better than clindamycin in oily skin types.
grade-b Notable High See all 5 studies
Most evidence suggests that in subjects with dyslipidemia that supplemental niacin at the pharmacological dose results in a decrease in circulating LDL-C, although to a lesser magnitude than it influences HDL-C
grade-b Notable Very High See all 8 studies
There appears to be a large decrease of triglycerides in subjects with dyslipidemia given pharmacological doses of niacin; the magnitude being greater than most supplements (but lesser than fish oil)
grade-b Minor High See all 7 studies
There appears to be an increase in fasting glucose concentrations among users of pharmacological doses of niacin when compared to controls, thought to be related to insulin resistance.
grade-b Minor - See study
One meta-analysis found a decrease in the risk of developing coronary heart disease when compared to control.
grade-b Minor High See all 7 studies
Chronic supplementation of pharmacological doses of niacin appears to increase fasting insulin concentrations when compared to control subjects.
grade-b Minor Very High See all 5 studies
Subjects given pharmacological doses of niacin appear to experience a decrease (worsening) of insulin sensitivity; the mechanisms behind this are not currently established.
grade-b Minor Very High See all 3 studies
Mixed evidence, but a possible decrease in the risk of myocardial infarction rates with niacin supplementation (overall mortality from cardiovascular diseases doesn\'t seem to be altered).
grade-b Minor Very High See 2 studies
There may be a decrease in the rates of strokes among subjects (dyslipidemics) using pharmacological doses of niacin when compared to controls
grade-b - Very High See 2 studies
Despite the benefits towards circulating lipids, overall mortality from cardiovascular disease does not appear to be significantly altered with niacin usage in pharmacological doses.
grade-c Notable Very High See 2 studies
An increase in circulating adiponectin has been noted in subjects with health ailments (NAFLD or metabolic syndrome) to a moderate degree
grade-c Notable - See study
An increase in circulating leptin has been noted with supplementation of pharmacological doses of niacin in subjects with metabolic syndrome.
grade-c Notable Very High See 2 studies
Alongside decreases in triglycerides and LDL-C, the concentrations of vLDL-C also appear to be decreased in response to niacin supplementation.
- See all 4 studies
Mixed evidence, including null evidence, in different populations as to whether apolipoprotein AI is increased or decreased; one study in subjects with low HDL-C noted an increased (which would be cardioprotective).
grade-c Minor - See study
When subjects with acne applied a nicotinamide metabolite to their face via a topical cream, subjects with burns appear to experience an increased rate of healing.
grade-c Minor - See study
There may be a reduction in fat oxidation rates when pharmacological doses of niacin are consumed by otherwise healthy subjects, although no changes in the metabolic rate occur due to an increase in the rate of glucose oxidation.
grade-c Minor - See study
An increase in hepatic glucose production has been noted in healthy subjects alongside a general state of insulin resistance.
grade-c Minor - See study
Insulin secretion (in response to glucose) appears to be hindered with chronic supplementation of pharmacological doses of niacin
grade-c Minor Very High See 2 studies
Topical application of nicotinamide and its analogues (not including niacin) appears to reduce reddening of the skin.
grade-c Minor - See study
Topical application of nicotinamide (not niacin) appears to increase elasticity of skin
grade-c Minor - See study
In subjects with hyperpigmented spots, topical application of nicotinamide cream (5%) was able to reduce the miscoloration more than control.
grade-c Minor Very High See 2 studies
Overall skin quality appears to be increased with topical application of nicotinamide containing creams and lotions; mildly but beneficially influencing most measured parameters.
grade-c Minor Moderate See all 3 studies
Total cholesterol is decreased with pharmacological doses of niacin owing to decreases of LDL and vLDL cholesterol, although the overall reduction is lesser due to a concomitant increase in HDL cholesterol.
grade-c Minor - See study
Topical application of nicotinamide appears to slightly reduce the appearance of fine wrinkles (crow's feet).
grade-c - Very High See all 4 studies
While a decrease in apolipoprotein B has been noted, most research suggests that it is not appreciably influenced.
grade-c - Very High See all 3 studies
While one study noted an increase in blood flow in subjects on medication who were given additional niacin, other studies do not find an interaction with niacin and blood flow.
grade-c - - See study
In otherwise healthy subjects, niacin does not appear to influence blood pressure.
grade-c - Very High See 2 studies
Pharmacological doses of niacin in obese dyslipidemics does not appear to confer fat loss properties.
grade-c - Very High See 2 studies
In otherwise healthy subjects as well as dyslipidemics, C-reactive protein does not appear to be altered in its concentration relative to control.
grade-c - - See study
Select cellular adhesion factors (iCAM and vCAM) do not appear to be influenced in their quantity when niacin is supplemented.
grade-c - - See study
The inflammatory cytokine IL-6 does not appear to be influenced by supplementation of niacin.
grade-c - - See study
Pharmacological doses of niacin in obese dyslipidemic men do not appear to increase circulating liver enzymes, suggesting no hepatotoxicity.
grade-c - - See study
Despite alterations in fat and glucose oxidation rates (favoring the latter), there does not appear to be any influence of pharmacological doses of niacin on the metabolic rate of healthy subjects.
grade-c - - See study
Plasma nitrate concentrations do not appear to be altered with supplementation of niacin.
grade-c - - See study
Circulating resistin concentrations do not appear to be influenced with supplementation of niacin.
grade-c - - See study
No significant influence of niacin supplementation on circulating TNF-a concentrations.
grade-c - Very High See 2 studies
Supplementation of pharmacological doses of niacin does not appear to influence body weight in any significant manner.
grade-d Minor - See study
One study in dyslipidemics found an increase in bilirubin associated with niacin supplementation.
grade-d Minor - See study
Supplementation of low dose niacin (100mg) repeatedly while in the fasted state appears to be associated with an increase in blood ketone levels.
grade-d - - See study
Circulating adrenaline concentrations during a fasting period do not appear to be altered when niacin is supplemented.
grade-d - - See study
Supplementation of niacin during a fasting period does not appear to influence circulating cortisol concentrations.
grade-d - - See study
Circulating glucagon concentrations do not appear to be altered when niacin (100mg every hour) is supplemented during a fasting period.

Studies Excluded from Consideration

Note: The above HEM includes all forms of Vitamin B3 (ex. niacin and nicotinamide) with entries using niacin alongside statin/fibrate drugs being included under the condition the control group is also given said pharmaceuticals

  • Combination of drug-niacin compared to placebo only, rather than drug-placebo[1][2][3]

  • Used aspirin to reduce the flush, but did not have an aspirin only placebo group[4]

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Things to Note

Primary Function:

Also Known As

Niacin, B3, Vitamin B3

Do Not Confuse With

Nicotine (Unrelated to nicotinic acid)

Goes Well With

  • Aspirin or Laropiprant (both reduce flushing from niacin, but do not appear additive)

  • Niacin supplements are known to cause the 'Niacin flush', a medically benign warm/flushing sensation usually in the face (differing from beta-alanine tingles); nicotinamide supplements do not have this effect

  • High (undisclosed) doses of niacin that have been used in attempts to mask urine drug tests are noted in a few case studies to be associated with multiorgan failure

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Click here to see all 277 references.