Vitamin B3 / Niacin Side Effects, Benefits & Foods

Niacin side effects - Dr. Axe

Vitamin B3, also called niacin vitamin and niacinamide, is an important lipid-altering, water-soluble vitamin that can be found in many common foods including certain types of meat and organ meat, tuna fish, seeds, mushrooms and others.

Niacin is a part of the vitamin B complex, along with other B vitamins including Vitamin B1 (thiamine), Vitamin B2 (riboflavin) and more.

Vitamin B3, which is usually medically referred to as niacin, comes in 3 forms: nicotinic acid, Niacinamide and Inositol Hexaniacinate. Vitamin B3 niacin has been studied extensively and shows positive results treating a wide range of many commonly occurring health problems.

Niacin is an important vitamin for maintaining a healthy cardiovascular system and metabolism- especially balancing blood cholesterol levels. In addition niacin helps with brain function, healthy skin formation and maintenance and even preventing or treating diabetes. (1)

However, according to recent studies, there are certain known niacin side effects that can occur when taking niacin-containing medications or supplements in high doses. The common niacin side effects are headaches, dizziness, low blood pressure and more. Continue reading for a complete list of possible side effects, benefits, sources and signs of deficiency.

Niacin Side Effects, Interactions and Concerns

Studies to date have examined the efficacy, safety, adverse effects, and pharmacologic properties of niacin. While at this time there is still more formal research needed to draw definite conclusions, initial studies have pointed to the fact that niacin can be hard to tolerate for some people, resulting in certain unwanted niacin side effects.

When weighing the positive attributes of taking niacin with the potential for patients experiencing niacin side effects, researchers have found evidence that niacin, used alone or combined with other drugs or supplements, has favorable effects, especially for treating cardiovascular diseases. (2)

However, because of the unusual range of possible niacin side effects, doctors recommend that niacin be taken carefully and with instruction from your doctor along with monitoring when taking any sort of high dose because niacin might cause niacin side effects.

If you’re eating foods rich in niacin, the chances that you’ll experience side effects are very slim. However, it’s possible to experience niacin side effects when taking supplements, especially if you have high doses. The following niacin side effects seem to occur most often in people who are taking high dose supplements and who have pre-known medical conditions. Niacin might cause:

  • Nausea or vomiting
  • Skin reactions, rashes
  • Headaches
  • Dizziness
  • Allergic reactions: Niacin supplements — including time release niacin — can cause allergies because some contain histamines, chemicals substances that can trigger allergic symptoms to be released
  • Heart problems: High doses of niacin may increase the risk of irregular heartbeats
  • Diabetes: Niacin and niacinamide might increase blood sugar. People with diabetes who take niacin or niacinamide should check their blood sugar carefully.
  • Worsened gallbladder or liver disease symptoms
  • Aggravated gout symptoms.
  • Low blood pressure
  • Stomach or intestinal ulcers
  • Problems after surgery controlling blood sugar levels


VitaminB3 Side and Niacin Side Effects Chart


Medications that contain niacin or prescription niacin in high doses may be able to cause uncomfortable symptoms related to muscle pain, digestive distress and skin inflammation. In a recent study, some patients reported niacin side effects including digestive problems, such as diarrhea and ulcers. (3) Other studies have shown that certain people are prone to experiencing muscle damage, gout, rashes, skin ulcerations and other serious skin-related problems when taking high doses of vitamin B3 niacin. (4)

And researchers think niacin may even has the possibly to increase the risk for diabetes in certain cases. If you are taking any medications or daily supplements and experiencing any negative niacin side effects, talk with your doctor about whether your medication may be to blame and if you should continue treatment or try another approach.

Other medications that are often taken with niacin, contain niacin or interact with niacin include colestipol, laropiprant, lovastatin, simvastatin and inositol hexanicotinate.

All of this being said, niacin has many useful benefits and is still commonly prescribed today despite the possibility for experiencing certain niacin side effects. (5)

There’s evidence that niacin can help to lower the risk of developing neurodegenerative diseases including Alzheimer’s disease, memory loss, eye disorders like cataracts, acne and skin flair ups, osteoarthritis, circulation problems, migraine headache, dizziness, and learning disorders like ADHD.

Signs and Symptoms of Vitamin B3 Niacin Deficiency

A deficiency in dietary niacin is uncommon in developed countries where malnutrition is not commonly seen. Clinical symptoms of a vitamin B3 niacin deficiency are usually categorized as the “3 D’s”: dermatitis (skin rashes), diarrhea, or dementia.

Diagnosis is usually clinical, and dietary supplementation with high doses of niacin is usually successful is resolving symptoms.

When a vitamin B3 niacin deficiency is seen, the following are signs and symptoms:

  • Pellagra- characterized by skin inflammation, hallucinations, digestive distress. Usually occurs in malnourished people or those with alcoholism and can include rash, stomatitis, diarrhea, and mental problems
  • Mucous membrane swelling- symptoms which affect the mouth, vagina and urethra tongue can cause pain in the mouth, increased salivation, and edema of the tongue, and ulcers
  • Skin symptoms include several types of lesions
  • Gastrointestinal (digestive) disturbances- symptoms include burning in the pharynx and esophagus,  stomach and abdominal discomfort, constipation, nausea, vomiting, and diarrhea
  • Brain impairment and psychosis- impaired consciousness, cognitive decline (dementia), disorientation, confusion, depression, mania, or paranoia.

Health Benefits of Vitamin B3 / Niacin

While there are some known niacin side effects that could potentially be dangerous, there are also many benefits to taking niacin and consuming foods rich in niacin. Here are some things niacin therapy can help with.

1. Improves Cholesterol Levels

Vitamin B3 niacin is considered an important treatment option for helping to reduce dangerously high cholesterol levels. Niacin has been proven to lower the risk of cardiovascular disease in patients with mixed dyslipidemia. Dyslipidemia is an elevation of plasma cholesterol, triglycerides or both.

In studies, supplementing with niacin has been shown to be very beneficial for those who are at an increased risk for heart attack, stroke, or other forms of heart disease due to having high LDL cholesterol levels (the “bad” kind of cholesterol), low levels of HDL cholesterol (the “good” kind)  and elevated triglyceride levels. (6)

Several studies have shown that vitamin B3 niacin can boost levels of good HDL cholesterol and lower triglycerides just as well as certain prescription drugs when given in high doses. (7)

Niacin also helps to lower bad LDL cholesterol. It’s commonly prescribed in combination with statins for cholesterol control, such as Crestor, Lescol, or Lipitor. (8a)

As previously mentioned, niacin side effects that may impact heart health are still being investigated. Although at this time it is believed that the positive attributes of niacin outweigh the potential risk for negative niacin side effects.

2. Lowers Cardiovascular Disease Risk

Aside from helping to balance cholesterol levels and triglycerides, vitamin B3 niacin has other benefits for heart health, including the ability to reduce atherosclerosis, which is the dangerous hardening of the arteries that can lead to heart disease.

Niacin plays a part in the reduction of inflammation and production of histamine, which is a chemical compound capable of dilating blood vessels and improving circulation.

For people who have already suffered from cardiac arrest or heart disease, including having a previous heart attack, vitamin B3 niacin can help to lower the risk of a reoccurrence taking place second one. In addition, niacin is an FDA-approved treatment for pellagra, a rare condition that develops from niacin deficiency.

Another niacin benefit is its ability to help lower lipoprotein. Elevated levels of lipoprotein(a) is a cardiovascular disease risk factor. In a 24-week trial, men with elevated lipoprotein levels saw declines in lipoprotein(a) levels when treated with high-dose, extended-release niacin. (8b)

3. Can Help Treat Diabetes

Vitamin B3 niacin may be helpful for treating diabetes because of the role it plays in balancing blood sugar levels. It’s believed that vitamin B3 in the form of niacinamide can help improve the efficiency of certain oral drug treatments that are used to control diabetes.

Most diabetic patients are able to effectively control blood glucose levels better with the help of niacin, and can also lower their risk of high blood cholesterol and heart disease which is commonly seen in patients with diabetes. (9)

Lowering “bad” cholesterol LDL levels is one of the first priorities in treating diabetic patients, and niacin is a proven method for doing so.

It’s important to note however that niacin is suspected for possibly contributing to complications with rising blood sugar levels, so if you have any known condition related to high glucose in the blood, speak with your doctor before supplementing with any form of Vitamin B3 niacin to avoid unwanted niacin side effects.

4. Maintains Skin Health

Some people use niacin or niacinamide for treating acne, especially severe cases of acne that can be very inflamed and painful (called inflammatory acne vulgaris).

Vitamin B3 in the form of niacinamide is prescribed as a natural treatment for healthy  skin and clearing acne when applied to the skin topically, and other people choose to take niacin or B vitamin complex supplements to help their symptoms.

Because niacin helps to reduce skin inflammation, flare ups, irritation, redness, and more, it is also used for treating skin conditions called bullous pemphigoid and granuloma annulare. (10) These are two inflammation-caused skin diseases that involve blistering of the skin which can be very painful and cause infection.

5. Supports Proper Brain Function

Studies have shown that vitamin B3 niacin can help protect against Alzheimer’s Disease and other age related brain disorders that result in cognitive decline. (11)

Additionally, Vitamin B3 niacin has been correlated with a decreased risk for many problems regarding poor brain function or loss of age-related thinking skills, including memory loss, migraine headaches, chronic brain syndrome, depression, motion sickness, insomnia, and even alcohol dependence

Niacin or niacinamide is also used for treating and preventing schizophrenia and hallucinations. Studies also show correlations between increased niacin intake and lower risks for attention deficit-hyperactivity disorder (ADHD).

6. Helps with Joint Mobility and to Treat Arthritis 

Some research shows that Vitamin B3 in the form of niacinamide can be effective in increasing joint mobility. Studies correlate niacin intake with lower levels of joint pain, enhanced muscle strength, and fewer symptoms associated with muscle or joint fatigue.

Prescribed high doses of niacinamide has been seen in studies to improve flexibility and reduce swelling, allowing some people who take niacinamide to be able to cut down on standard painkillers or medications for arthritis. (12)

As a treatment for osteoarthritis or bone and joint pain, niacin is normally prescribed in high doses for its anti-inflammatory effects. Reducing inflammation helps to lower the occurrence of symptoms of arthritis and to rebuild the joint cartilage that is crucial to mobility and strength.

7. Treats Pellagra, a Disease Caused by Low B Vitamin Levels 

A vitamin B3 niacin deficiency is attributed to causing the disease called pellagra, which is usually seen in poverty stricken areas or in those with alcoholism. Pellagra symptoms include weak muscles, digestive problems, and skin inflammation and irritation.

People who pellagra usually have very low levels of niacin and other B vitamins, which contribute to the disease, but other causes include problems with protein metabolism and the inability to convert certain amino acids. When vitamin B3 levels are not restored, someone with pellagra can die within several years due to the deficiency.

Nicotinic acid deficiency results most often from malnutrition as well as with chronic alcoholism. (13) Niacin is given to patients in third world countries who experience poverty and malnutrition, as well as those who are battling symptoms of alcoholism including nervousness, irritability, insomnia, and loss of consciousness.

The common treatment for pellagra is to prescribe high levels of the type of vitamin B3 called nicotinamide, which has the same vitamin function as niacin but is slightly different in terms of absorption and side effects.

8. Can Help Prevent Impotence (Erectile Dysfunction)

Impotence, also called erectile dysfunction, is the inability for a man to sustain an erection. This can interfere with the ability to have satisfying sexual intercourse and may be partially due to low blood flow and bad circulation, in addition to other factors like stress, fatigue, and illness.

Supplementing with Vitamin B3 niacin can help decrease impotence because niacin acts as a vasodilator that helps improve blood flow to the genital region. As a natural remedy, I recommend supplementing with Vitamin B3 niacin (250 mg) 3 times per day.

9. Can Help Prevent Birth Defects

Vitamin B3 has been shown to assist with preventing nicotinamide adenine dinucleotide (NAD) defects. NAD molecules are crucial for energy storage and DNA synthesis in cells, so increasing B3 levels in pregnant women could lower birth defect rates overall.

A 2017 article published highlighted that the disruption of NAD molecule creation caused malformations in both humans and mice. Additionally, vitamin B3 supplementation during pregnancy prevented malformations in mice. (14)

Despite the findings in the study, more human studies are required before vitamin B3/niacin is prescribed by doctors. “Researchers need to learn more about how pregnancy influences NAD levels in general, and what a healthy level is.” (15)


Niacin side effects - Dr. Axe


Niacin Dosage

The RDA (recommended daily allowance) for Vitamin B3 niacin is as follows, according to the USDA (16):

  • Children: between 2-16 milligrams daily, depending on age
  • Men: 16 milligrams daily
  • Women: 14 milligrams daily
  • Women who are pregnant and breastfeeding 17- 18 milligrams daily

Keep in mind that the ideal dosage of niacin depends on how you’re using it, your age, weight, gender, and specific needs.  For example, high doses of 2 to 3 grams or more are given to treat high cholesterol.

Niacin has the ability to possibly upset your stomach, so it’s usually recommended that you take any supplement containing niacin along with a meal so the food can help slow its absorption and prevent niacin side effects.

Depending on your needs and reason for using niacin, some health care providers may also recommend taking niacin along with aspirin, or an antihistamine, for a few weeks until tolerance to niacin develops.

Niacin is a water-soluble vitamin, which means it has the ability to travel through the blood stream once ingested in either food or supplement form, and for the kidneys to dispose of excess levels of the vitamin through urination when it isn’t needed for body function.

Water-soluble vitamins like niacin, and other B vitamins, must be replenished in the body very frequently through food or supplements because the body flushes them out almost daily, though getting niacin through food is preferable than niacin supplementation.

Take B Vitamins Together

Vitamin B3 niacin can usually be obtained through a healthy diet in high enough amounts to meet your daily needs, but if you are going to take a supplement containing B vitamins including niacin, look for a high quality supplement that is ideally made using whole food sources. This way your body is better able to absorb and use the nutrients and you don’t experience unwanted niacin side effects as much.

Consuming B vitamins together in a quality B Vitamin Complex supplement also allows them to work better in the body, since the B vitamins interact with one another to make absorption and conversion possible.  B vitamins can be beneficial in supporting the metabolism, heart, brain, and for muscle and joint health, but remember that it’s always preferable to consume plenty of whole foods that naturally contain all the vitamins and minerals you need.

Remember you want to make sure you do not overly consume any one nutrient through synthetic vitamins, whether its water-soluble or not,  because excessive intakes can lead you to experience side effects.  The same is true of niacin side effects; they are usually experienced in individuals with existing medical problems when niacin is taken at high doses.

Try consuming high-quality cuts of meat including free-range and grass fed poultry and beef, fish, beans, nuts, and seeds in order to make sure you acquire enough B vitamins. Consuming foods that contain niacin should not result in levels high enough to cause any harmful niacin side effects.

 Top 11 Vitamin B3 / Niacin Foods

These percentages are based on the adult RDA of 16 mg/daily for adult males, adult females should consume roughly 14 mg/ daily:

1. Beef Liver 

3 oz: 14.2 mg (89 percent daily value)

2. Chicken Breast

3 oz: 12.3 mg (76 percent daily value)

3. Tuna

1 can (about 3 oz.): 11.3 mg (71 percent daily value)

4. Sunflower Seeds

1 cup: 9 mg (56 percent daily value)

5. Grass Fed Beef

3 oz: 9 mg (56 percent daily value)

6. Lamb

3 oz cooked: 6.9 mg (43 percent daily value)

7. Salmon

3 0z: 6.7 mg (42 percent daily value)

8. Split Green Peas

1 cup oz: 5.7 mg (35 percent daily value)

9. Sardines

1 can in olive oil: 4.8 mg (30 percent daily value)

10. Turkey

3 oz: 4 mg (25 percent daily value)

11. Mushrooms

1 cup white button mushrooms: 2.5 (16 percent daily value)

12. Tahini (sesame seed paste)

2 Tbsp: 2.2 mg (14 percent daily value)


Vitamin B3 and Niacin Rich Foods Chart Infographic


Adding More Vitamin B3 Niacin to Your Diet

You can increase the amount of Vitamin B3 niacin in your diet by making some of these recipes below, which all include foods that are naturally high in niacin and other B vitamins:

  • For breakfast, start your day by having this filling Turkey Breakfast Sausage served with veggies and cage-free organic eggs.
  • for a healthy mid morning snack, have some Greek yogurt with this Grainless Granola which features Vitamin B3 packed sunflower seeds.
  • Make a filling and protein-packed Garlic Lamb Roast that will leave you with extra leftovers for the week.
  • Try making this Garlic Chicken Recipe for dinner and pair it with some nutrient-rich roasted veggies for extra nutrients.
  • When you’re short on time, you can prepare this Crockpot Turkey Stew even while you’re not home!
  • As a side dish, try making this Mushroom Soup or  Broccoli Salad which has nuts, seeds, and veggies that supply niacin.

READ NEXT: Top 10 Vitamin B12 Foods

From the sound of it, you might think leaky gut only affects the digestive system, but in reality it can affect more. Because Leaky Gut is so common, and such an enigma, I’m offering a free webinar on all things leaky gut. Click here to learn more about the webinar.

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