Amount of Evidence: Very High Potential Benefits: Very High Safety: Reasonable
TABLE OF CONTENTS
What is vitamin B3 (niacin)?
Vitamin B3 is a water-soluble vitamin that is essential for many functions in your body, such as increasing your NAD+ levels, energy production, healthy metabolism, protection against oxidative stress, reparation of damaged DNA, and much more. Vitamin B3 supplements are considered by many to be one of the most (if not the most) effective supplements for increasing human healthspan. There are 4 main forms of supplemental vitamin B3: niacinamide (also known as nicotinamide), nicotinic acid (sometimes simply called niacin), NR (nicotinamide riboside), and NMN (nicotinamide mononucleotide). In this article, we will look at vitamin B3’s main benefits, potential side effects, and how to use it the right way.
Potential benefits
It is important to note that all of the potential benefits mentioned below are dose-dependent. In general, the higher the dose you take, the more pronounced the effects will be. However, they do reach a plateau at a certain point. We will discuss the best dosing protocol later in this article.
Major benefits
Correcting a niacin deficiency – Severe vitamin B3 deficiency is called pellagra. The main symptoms of pellagra are “the three Ds”: dementia, diarrhea, and dermatitis (in severe cases, a fourth D can be added, death). Although it is unlikely that you will ever experience such a deficiency, an inadequate supply of dietary niacin can still lead to many health problems. The most common signs of niacin deficiency include fatigue, exercise intolerance, depression, and accelerated skin aging. People with a niacin deficiency also have a higher risk of developing esophageal cancer, skin cancer, and leukemia. The reason for this could be an impaired ability of the body to repair DNA.
Increased NAD+ levels – Because of niacin’s ability to support our NAD+ levels, it appears to be one of the most effective supplements for slowing the aging process and increasing human healthspan. Increased NAD+ levels may be responsible for many of the other benefits, but the connection has not yet been proven.
Increased HDL cholesterol – Niacin is undoubtedly the most effective supplement for increasing HDL cholesterol. It is important to note that this effect only applies to nicotinic acid and extended-release niacin.
Decreased LDL cholesterol – Although niacin does not affect LDL cholesterol levels as much as HDL cholesterol levels, vitamin B3 supplements still result in a significant lowering of LDL cholesterol (both LDL-C and VLDL-C). Again, this effect applies only applies to the two forms mentioned above.
Lower triglycerides – There appears to be a significant lowering of triglycerides in individuals taking high doses of niacin. While this effect has only been observed in individuals with dyslipidemia, it probably applies to people without this condition as well.
Minor benefits
Decreased risk of strokes – Studies available to date show that niacin supplementation reduces the risk of stroke, especially in people with dyslipidemia.
Reduction in acne – This effect is most notable in people who use niacinamide topically. However, oral use of niacin is also likely to reduce the severity of acne.
Reduced wrinkles – Both topical use of niacinamide and oral use of niacin supplements have been shown to reduce wrinkles. Oral supplements are especially helpful for wrinkles caused by long-term sun exposure. With topical niacinamide, this effect is most notable for wrinkles around the eyes.
Detoxification – Vitamin B3 appears to release toxins from fat cells. The toxins can then be flushed from the body through sweating. Therefore, taking high doses of vitamin B3 before exercising and going to the sauna after appears to be an effective way to detoxify heavy metals and other toxins.
Skin quality – Topical nicotinamide makes the skin more elastic and reduces the reddening of the skin. In people with hyperpigmented spots, topical nicotinamide reduces skin pigmentation. Also, when topical niacinamide is applied to burned skin, the skin heals faster.
Higher leptin production – Leptin is a hormone that helps achieve and maintain a normal weight. Niacin supplements have been shown to increase the concentration of leptin in the blood.
Decreased risk of CAD – One meta-analysis found that vitamin B3 supplements reduce the risk of CAD (coronary artery disease).
Lower risk of myocardial infection – While this effect may not be significant, niacin supplements appear to prevent you from myocardial infection to some extent.
Production of ketones – When taken in a fasted state, even low doses of niacin can increase the production of ketone bodies.
Brain protection – In one study, nicotinamide riboside was able to prevent age-related brain damage and improve memory function in mice. This effect could apply to other forms of vitamin B3 as well since it is likely connected with increased NAD+ levels.
Reduced heart and liver fat – While vitamin B3 does not appear to reduce overall body fat, nicotinic acid has been shown to help burn fat around the liver and the heart.
Unproven benefits
The effect of vitamin B3 supplements on these parameters is either not sufficiently researched or the science shows little to no efficacy in these areas.
Lower risk of death from cardiovascular diseases – Niacin supplements do not appear to significantly reduce mortality associated with cardiovascular diseases.
Apolipoprotein A – One study suggests an increase in ApoA, which would be cardioprotective. However, other studies show little or no effect on ApoA levels.
Apolipoprotein B – The reduction in ApoB has been noted in scientific studies but it is insignificant and has little to no impact on your health.
Blood flow – Most studies show that niacin does not increase blood flow. There may be a slight improvement in people who take niacin regularly over a long period of time and have low HDL-C levels.
Blood pressure – Niacin does not appear to affect blood pressure in healthy individuals. In hypertensives, niacin appears to be able to lower blood pressure in the short term.
Body fat – There are only 2 studies that have examined this effect, but none have shown any benefit of niacin for overall fat loss. However, nicotinic acid does lead to a reduction of fat around the liver and the heart.
Reduction in CRP (C-reactive protein) – Niacin supplements do not appear to lower CRP in healthy individuals or in dyslipidemics.
Inflammation – Vitamin B3 has no noticeable effect on inflammation.
Prevention of muscle atrophy – Muscle NAD+ levels have been shown to protect muscle mass as we age. As of 2022, only nicotinic acid has been proven to increase muscle NAD+.
Possible side effects
These side effects may only occur if you take high doses of vitamin B3 and often do not apply to all forms.
Niacin flush – After taking niacin supplements (especially in the form of nicotinic acid), the skin may become red and itchy for about 2 hours. This side effect is quite common and (with rare exceptions) not dangerous. Niacin flush can even be considered a positive effect, as it has some short-term and long-term benefits. The reason we put niacin flush in the side effect category is that it is not a pleasant experience for most people. The flushing becomes less intense over time.
Weakness and lack of energy – This is another possible short-term effect that some people experience. Fortunately, it is not as common as niacin flushing when taking nicotinic acid. Some people actually feel energized after taking vitamin B3.
Decreased insulin sensitivity and diabetes – Long-term supplementation of high doses of nicotinic acid has been associated with worsened insulin sensitivity. Fasting insulin concentrations also tend to be higher in individuals who take niacin than in those who do not.
Increased blood glucose – There appears to be a slight increase in fasting blood glucose levels in individuals taking high doses of nicotinic acid. Fortunately, this effect is small and may not occur in healthy individuals.
Liver damage – Very high doses of certain forms of B3 supplements may cause liver failure. In particular, slow-release niacin is the main form to be concerned about. Other forms do not appear to damage the liver nearly as much and the side effect can be mitigated to a large extent.
Sirtuin inhibition – This side effect only applies to niacinamide. While niacinamide only inhibits sirtuin activity for a few hours after taking it, it is enough of a reason to choose other forms. However, there is also a way to get around this effect by boosting an enzyme called NAMPT. In order for niacinamide to increase NAD+ and increase sirtuin activity, it must first be converted to NMN. This conversion requires an enzyme called NAMPT. NAMPT peaks in the morning and early afternoon. NAMPT can also be increased by exercise, caloric restriction, and resveratrol.
Worsened allergies – Vitamin B3 can lead to the release of histamine, which can increase the intensity of allergies in the short term.
Who should avoid taking vitamin B3?
You should probably avoid high doses of vitamin B3 if you:
have diabetes or are predisposed to them
suffer from liver damage
have been diagnosed with NAFLD (supplementation of 1000 mg of niacin per day has been shown to nearly double insulin levels in individuals with NAFLD)
Who will benefit the most?
You should definitely consider taking vitamin B3 supplements if you:
are experiencing symptoms of vitamin B3 deficiency
suffer from a digestive disorder (such as Crohn’s and megaduodenum)
are under a lot of physical and mental stress
have problems with your cholesterol levels
Forms of vitamin B3
There are 7 main forms of vitamin B3 supplements. Each has its distinct advantages and disadvantages.
Niacinamide – Also known as nicotinamide and NAM, this is the most popular form of vitamin B3. Almost all B-complex or B3 supplements contain this form because it is the cheapest one to produce. The main problem with niacinamide is that it inhibits sirtuin activity for at least an hour after taking the supplement. Niacinamide also does not seem to affect NAD+ levels nearly as much as the other forms. For this reason, niacinamide is not as effective for increasing healthspan and lifespan as many of the other forms.
Nicotinic acid – This form, often simply called niacin, is often used in high doses to alter cholesterol levels. It is also the form that causes niacin flush because we absorb this form rapidly. The disadvantage of nicotinic acid is that it may increase your risk of diabetes. The main reason to take this form instead of the other ones is that it is more effective in most areas (particularly, increasing NAD+ and altering cholesterol levels) and significantly less expensive than NR or NMN.
Sustained-release niacin – This form was invented to avoid the flushing effect of nicotinic acid by releasing niacin over the course of 12+ hours. Unfortunately, it was soon discovered that sustained-release niacin is associated with high rates of hepatotoxicity (liver damage.)
Extended-release niacin – In this form, niacin is released for around 8 hours. Fortunately, this version does not seem to cause liver toxicity and it doesn’t cause nearly as much flushing as regular nicotinic acid. The only problem is that manufacturers sometimes mislabel their niacin products, calling them extended-release even if they are sustained-release.
Inositol hexanicotinate – This form is slowly broken down in the body and takes 6-12 hours to get absorbed. Unfortunately, it does not release enough niacin for the flushing and cholesterol-lowering effect. On top of that, this form, if taken in high doses over an extended period of time, can cause significant liver damage.
NR (nicotinamide riboside) – This relatively new form may be superior to those previously mentioned in that it has much less potential for harm. NR also does not cause flushing, but does not have the same effects on cholesterol levels as nicotinic acid.
Severe vitamin B3 deficiency is called pellagra. The main symptoms of pellagra are “the three Ds”: dementia, diarrhea, and dermatitis (in severe cases, a fourth D can be added, death). Although it is unlikely that you will ever experience such a deficiency, an inadequate supply of dietary niacin can still lead to many health problems. The most common signs of niacin deficiency include:
fatigue
exercise intolerance
depression
accelerated skin aging
bright red tongue
a pigmented skin rash following sun exposure
impaired circulation
headaches
impaired memory
hallucinations
oral ulcers
tongue swelling
diarrhea
Keep in mind that these signs are just indications of deficiency. The fact that you experience some of them does not necessarily mean that you need more vitamin B3. On the other hand, some people may have a deficiency even though they are completely asymptomatic.
With that said, if you experience many or most of these symptoms, there is a high chance you are not getting enough niacin. The more of these symptoms you experience and the more severe they are, the more likely you are deficient.
How much vitamin B3 should you take?
The RDA (recommended daily allowance) for vitamin B3 is 16 mg for men and 14 mg for women. This amount is, in most cases, sufficient to prevent symptoms of deficiency.
However, that does not mean you can not get even more benefits from a higher amount of niacin. The benefits mentioned above in this article often have to do with much higher doses of vitamin B3.
Alcohol, sun exposure, digestive disorders, stress, and a few other factors increase your need for niacin.
Most of the benefits described above applyonly to high doses (500-2000 mg of vitamin B3).
For nicotinic acid, 500 mg seems to be the optimal amount to take. 1000-2000 mg does result in additional benefits but also carries some significant risks. Only take 1000+ mg if you have a valid reason to do so, and consult your doctor before doing so. If 500 mg is too much for you and the flushing effect is too uncomfortable, you will still derive reasonable benefits from 100+ mg.
Niacinamide is safer than nicotinic acid in many ways, but taking high doses of this form is not as effective for increasing healthspan as taking other forms. The main benefit of niacinamide is to correct vitamin B3 deficiency.
If you choose to take niacinamide to raise NAD+ levels, 100 mg appears to be the optimal amount. Any more than that will probably not get converted unless you have an abnormally high amount of the NAMPT enzyme.
As for NR and NMN, 1000 mg per day seems to be the optimal amount. Do not take higher doses than 3000 mg of niacinamide, NR or NMN without consulting your doctor!
Regardless of which form you decide to take, start low and gradually increase your dose.
Food sources of vitamin B3
Legumes, nuts, fish, mushrooms, certain vegetables and organ meats are the richest sources of vitamin B3.
Grains and seeds are considered a great source of niacin. Unfortunately, 85-90% of the niacin in whole grains and 40% of the niacin in seeds are bound and cannot be absorbed. However, you can release some of the niacin by sprouting and fermenting these foods.
Your body can also synthesize niacin from protein (specifically, from an amino acid called L-tryptophan. However, other nutrients are required for this conversion. Specifically, you need sufficient amounts of vitamin B6, iron, and riboflavin. This means that even if you do not get enough vitamin B3 from food, you may not suffer from a niacin deficiency if you consume a high amount of the three nutrients. The easiest way to find out how much niacin (and other nutrients) you are getting in your diet is with Cronometer.com – the app is free and allows you to track all vitamins, minerals, and more.
Best time to take vitamin B3
Always take vitamin B3 supplements with a meal, and divide the dose evenly across each meal.
Taking the supplement on an empty stomach may cause stomach upset and intensify the flushing effect.
If you are taking nicotinic acid to lower cholesterol, you should not eat large amounts of carbohydrates for 3-6 hours after taking it.
If you decide to take niacinamide, take it either in the morning or the early afternoon. This is when the enzyme called NAMPT is at its peak. NAMPT is needed to convert niacinamide into NMN.
For other forms of niacin, it does not matter much whether you take them in the morning or in the evening although taking the supplement after dinner is likely the best option.
Interactions with other supplements
TMG TMG (trimethylglycine) can protect against potential liver toxicity caused by vitamin B3 supplements. For optimal effects, pair nicotinic acid or niacinamide with an equal amount of TMG. If you’re taking NR or NMN, combine it with half the dose of TMG.
Glycine If you’re taking nicotinic acid, combine it with half the dose of glycine to prevent liver toxicity. For example, for 1000 mg of nicotinic acid, include 500 mg of glycine. With the other forms of vitamin B3, you don’t need to worry about glycine.
CoQ10 Combining CoQ10 with any form of vitamin B3 can improve mitochondrial performance.
Apple pectin Apple pectin has been shown to reduce the flushing effect (just as effectively as aspirin) by slowing down the absorption of vitamin B3.
Resveratrol Resveratrol helps niacinamide turn into NMN by boosting an enzyme called NAMPT. NAMPT is needed for the conversion.
Aspirin Taking 325 mg of aspirin 20-30 minutes before you take niacin is shown to prevent flushing. However, beware that there is a 40% increase in the risk of gastrointestinal bleeding when aspirin is combined with niacin.
Statins Taking vitamin B3 along with some statins may increase the risk of muscle damage in some people.
Alcohol Alcohol itself can cause flushing and itchiness. When combined with nicotinic acid supplements, alcohol is likely to intensify the flush. Consuming alcohol and vitamin B3 together might also lead to liver damage.
Where to buy vitamin B3
Amazon seems to be the best option for ordering vitamin B3 supplements in most countries. They offer some very affordable products that are backed by many positive reviews. Also, you can choose from a wide range of brands there without having to spend time searching through other markets on the internet.
The most important thing you should pay attention to is that some brands display the dosage per serving and not per pill or capsule. Therefore, you may accidentally buy something that is less potent than you intended. Do not fall for this marketing trick.
FAQ
Vitamin B3 can be taken daily and does not need to be cycled.
Yes. Unless you get the flush when falling asleep, niacin won’t impact your sleep in any negative way. Taking it in the evening may actually be preferred.
Niacin supplements do not expire. They can, however, lose potency over time. To minimize this, keep your supplements in a cold, dark, and dry place.
The flushing effect typically lasts for 1-2 hours, depending on the dose you take and whether you take it with food or without it.
In short, taking niacin leads to the production of prostaglandins. Prostaglandins cause blood vessels in the skin to dilate and enlarge. Therefore, more blood flows into your skin, which makes it red and itchy.
You will notice changes in both your HDL and LDL cholesterol levels in about 6 weeks.
Niacin has a half-life of 20-45 minutes. Therefore, it takes about 2-6 hours to leave your system.
Liver damage is the primary and most notable symptom of toxicity.
There are a few ways to prevent the flushing effect. 1) Lower your dose and build your way up gradually 2) Take 325 mg of aspirin 20-30 minutes before taking nicotinic acid 3) Consider apple pectin, it can have a similar effect to aspirin in lowering the intensity of the flush. 4) Consider switching to extended-release niacin (but beware of the sustained-release form since it can cause serious damage to your liver)
No, it doesn’t. Vitamin B3 does not interfere with fasting in any notable way. However, if you take the nicotinic acid form, taking it on an empty stomach significantly increases the intensity of niacin flush.
References
Most of the information provided in this guide is based on scientific research that can be found and verified in the PubMed medical library. We excluded from consideration studies that are either confounded or have a high conflict of interest.
Anecdotal evidence (from reports on Reddit, YouTube, and other sources) is also taken into account unless it contradicts scientific research.
