Understanding the Role of Niacin in Health

Niacin Side Effects vs. Benefits: 9 Reasons You Need Vitamin B3


Niacin side effects - Dr. Axe

Niacin is an incredibly important water-soluble vitamin that plays a role in many aspects of health, from brain function to heart health and beyond. Although associated with a number of potential niacin side effects, it’s also one of the few micronutrients frequently prescribed by physicians to treat health concerns like high cholesterol, skin conditions, schizophrenia and more — through both supplementation and niacin foods.

So what is niacin good for, and how can it improve your health? Keep reading for everything you need to know about this essential vitamin and why you should make sure you’re getting enough in your diet.

What Is Niacin?

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 meats and organ meats, tuna fish, seeds, mushrooms and more.

It is a part of the vitamin B complex, along with other B vitamins, including vitamin B1 (thiamine), vitamin B2 (riboflavin) and others. Vitamin B3, which is usually referred to as niacin, comes in three forms: nicotinic acid, niacinamide and inositol hexaniacinate. Vitamin B3 niacin has been studied extensively and has been shown to aid in treating a wide range of many commonly occurring health problems.

So what is niacin used for, what does niacin do to the body and how can it affect your health? Vitamin B3 is an important vitamin for maintaining a healthy heart and metabolism, plus aiding in the balance of blood cholesterol levels. In addition, it helps with brain function, skin health and even preventing or treating diabetes. (1)

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

Health Benefits

While there are some known niacin side effects that could potentially be dangerous, there are also many benefits to consuming plenty of vitamin B3 foods or considering supplementation. Here are some things that niacin therapy can help with.

1. Improves Cholesterol Levels

Niacin is considered an important treatment option for helping to lower cholesterol levels. This is because niacin has been proven to lower the risk of heart disease in patients with mixed dyslipidemia, which 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 caused by having high levels of bad LDL cholesterol levels, low levels of beneficial HDL cholesterol or increased triglyceride levels. (2)

Several studies have shown that niacin can boost levels of good HDL cholesterol and lower triglycerides just as well as certain prescription drugs when given in high doses. (3) Plus, niacin also helps lower bad LDL cholesterol. In fact, it’s commonly prescribed in combination with statins for cholesterol control alongside medications like Crestor, Lescol or Lipitor. (4)

2. May Reduce the Risk of Heart Disease

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

For those who have already suffered from cardiac arrest or heart disease, including having a previous heart attack, vitamin B3 can help reduce the risk of recurrence by lowering levels of low-density lipoproteins in the blood, which is one of the major risk factors for heart disease. In one 24-week trial, men with high lipoprotein saw declines in lipoprotein(a) levels when treated with high-dose, extended-release niacin. (5)

3. Regulates Blood Sugar Levels

One of the biggest benefits of niacin is its ability to balance blood sugar levels and help control diabetes symptoms. In fact, it’s believed that vitamin B3 in the form of niacinamide benefits diabetes by improving the function of beta cells, which are the cells that are responsible for the production of insulin. (6)

Not only are diabetic patients often able to effectively control blood sugar levels better with the help of niacin, but niacin might also lower their risk of high blood cholesterol and heart disease, both of which are commonly seen in people with diabetes. (7)

It’s important to note that some research suggests that niacin might also contribute to complications with rising blood sugar levels, so if you have any known condition related to high blood sugar, speak with your doctor before supplementing with any form of niacin to avoid unwanted niacin side effects. (8)

4. Improves Skin Health

Some people use niacin or niacinamide for improving skin health and treating conditions like acne and inflammation. In fact, vitamin B3 in the form of niacinamide is prescribed as a natural skin care treatment to help clear acne when applied to the skin topically, and other people choose to take niacin or B vitamin complex supplements to reduce symptoms. (9)

Because niacin is able to reduce skin inflammation, flare-ups, irritation, redness and more, it is also used for treating skin conditions like bullous pemphigoid and granuloma annulare. (10, 11) These are two inflammatory conditions that involve blistering of the skin, causing symptoms like pain and an increased risk of infection.

5. Supports Brain Function

Studies have shown that vitamin B3 benefits brain health and may help protect against Alzheimer’s disease and other age-related brain disorders linked to cognitive decline. (12)

Niacin or niacinamide is also used for treating and preventing schizophrenia and hallucinations. (13) Plus, some studies and case reports have found therapeutic effects of niacin for depression, bipolar disorder and other psychiatric disorders as well. (14, 15)

Niacin side effects - Dr. Axe

6. Promotes Joint Health

Some research shows that vitamin B3 in the form of niacinamide can be effective in increasing joint mobility. In fact, studies have found that increased niacin intake may be associated with lower levels of joint pain plus decreased inflammation associated with conditions like osteoarthritis. (16)

Prescribed high doses of niacinamide have been seen in studies to improve flexibility and reduce swelling, allowing many who take niacinamide to be able to cut down on standard painkillers or medications for arthritis. (17)

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

7. Treats Pellagra

A vitamin B3 deficiency can cause pellagra, a condition that is most often seen in poverty-stricken areas and in those with eating disorders or alcoholism. Pellagra symptoms can include issues like weak muscles, digestive problems, inflammation and skin irritation.

People with pellagra usually have very low levels of niacin and other B vitamins, which is caused by either a low intake of niacin or other underlying factors, such as issues with protein metabolism or amino acid absorption. When vitamin B3 levels are not restored, those with pellagra can die within just a few years as a result of the deficiency.

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

8. Helps Prevent Impotence

Impotence, also called erectile dysfunction, is the inability for a man to sustain an erection. This can interfere with sexual satisfaction 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 can help prevent erectile function because niacin acts as a vasodilator and helps improve blood flow throughout the body. Studies show that 1,500 milligrams of niacin daily is enough to improve sexual function in men suffering from impotence. (18)

9. Protects Against 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 potentially lower birth defect rates overall.

According to one 2017 article, the disruption of NAD molecule creation can cause malformations in both humans and mice. Conversely, vitamin B3 supplementation during pregnancy may actually help prevent malformations in mice. (19)

Despite the findings in the study, more human studies are required before vitamin B3/niacin is prescribed by doctors. In particular, further research is needed to understand how pregnancy may impact NAD levels and to determine what a healthy level should be for a healthy pregnancy.

Vitamin B3 Uses in Traditional Medicine

Foods high in niacin are typically rich in a long list of other important nutrients as well, which is why most can fit seamlessly into many forms of traditional medicine for their healing and health-promoting properties.

For instance, animal proteins, such as meat, poultry and fish ,are common components in Traditional Chinese Medicine that are believed to tonify the qi, also known as the vital force that is essential to sustaining life and maintaining mental and physical health. Additionally, fish is thought to help fight fatigue, beef is used to strengthen the spleen and chicken is believed to keep the kidneys functioning properly.

Plenty of plant-based niacin foods can be consumed on an Ayurvedic diet as well. Sweet potatoes, for example, are satisfying, easy to digest and excellent for liver health, while asparagus is thought to reduce inflammation, help alkalize the body and nourish the blood.

Niacin Side Effects, Interactions and Concerns

Many studies to date have examined the efficacy, safety, adverse effects and pharmacologic properties of niacin. While more research is still needed to draw definite conclusions, some initial studies indicate that niacin can be hard to tolerate for some people, which may result in several undesirable niacin side effects.

When weighing the positive attributes of taking niacin with the potential niacin side effects, researchers have found that vitamin B3, when used alone or combined with other drugs or supplements, has favorable effects, especially when it comes to heart health. (20) However, because of the unusual range of possible niacin side effects, doctors recommend that supplementation should be taken only as directed and preferably under medical supervision for those with underlying health conditions.

If you’re eating foods rich in niacin, the chances of adverse side effects are very slim. Taking high doses of supplements, on the other hand, can cause a wide range of possible symptoms, including:

  • Nausea or vomiting
  • Skin reactions and rashes
  • Headaches
  • Dizziness
  • Allergic reactions: Niacin supplements — including time release niacin — can cause allergies because some contain histamines, which are chemical substances that can trigger allergic symptoms
  • Heart problems and irregular heartbeats
  • Increased blood sugar
  • Worsened gallbladder function
  • Gout
  • Low blood pressure
  • Stomach or intestinal ulcers

Other medications that are often taken with niacin, contain niacin or interact with niacin include colestipol, laropiprant, lovastatin, simvastatin and inositol hexanicotinate. If you are taking any of these medications, experience any adverse side effects or have any concerns, be sure to talk with your doctor to determine the best dosage and course of treatment for you.

Vitamin B3 Side Effects

Deficiency Symptoms and Causes

A deficiency in niacin is generally uncommon in developed countries where malnutrition is rare. Some of the most common causes of deficiency include alcoholism, malnutrition, digestive disorders and prolonged use of certain medications that interfere with absorption.

Clinical symptoms of a vitamin B3 deficiency are usually categorized as the “4 D’s”: dermatitis (skin rashes), diarrhea, dementia and death. Diagnosis is usually clinical, and dietary supplementation with high doses of niacin is generally successful is resolving symptoms.

When a niacin deficiency is seen, the following are some of the most common 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 that affect the mouth, vagina and urethra tongue can cause pain in the mouth, increased salivation, swelling of the tongue and ulcers.
  • Skin symptoms, including several types of lesions.
  • Digestive disturbances — symptoms include burning in the pharynx and esophagus,  stomach discomfort, constipation, nausea, vomiting and diarrhea.
  • Brain impairment and psychosis — some studies have found a link between niacin and depression, impaired consciousness, cognitive decline, disorientation, confusion, mania or paranoia.

Top 15 Niacin Foods

There are plenty of foods high in niacin, making it easy and convenient to meet your daily needs by simply following a healthy diet. Plus, by getting the majority of niacin in food sources rather than supplements, you can also be sure that you’re getting plenty of other essential nutrients that your body needs as well.

Here are 15 of the top foods high in niacin to add to your diet: (21)

  1. Chicken — 1 cup: 19.2 milligrams (96 percent DV)
  2. Liver — 1 slice: 11.9 milligrams (60 percent DV)
  3. Tuna — 3 ounces: 11.3 milligrams (56 percent DV)
  4. Turkey — 1 cup: 9.6 milligrams (48 percent DV)
  5. Salmon — 3 ounces: 6.8 milligrams (34 percent DV)
  6. Sardines — 1 can: 4.8 milligrams (24 percent DV)
  7. Grass-Fed Beef — 3 ounces: 4.4 milligrams (22 percent DV)
  8. Sunflower Seeds —1 cup: 3.8 milligrams (19 percent DV)
  9. Peanuts — 1 ounce: 3.8 milligrams (19 percent DV)
  10. Green Peas — 1 cup: 3.2 milligrams (16 percent DV)
  11. Brown Rice — 1 cup, cooked: 3 milligrams (15 percent DV)
  12. Mushrooms — 1 cup: 2.5 milligrams (13 percent DV)
  13. Avocado — 1 cup, cubed: 2.6 milligrams (13 percent DV)
  14. Sweet Potatoes — 1 medium: 1.7 milligrams (8 percent DV)
  15. Asparagus — 1 cup: 1.3 milligrams (7 percent DV)

Supplements and Dosage

According to the USDA, the recommended daily allowance for vitamin B3 niacin is as follows:

  • 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 niacin dosage depends on how you’re using it as well as your age, weight, gender and specific needs. For example, when prescribing niacin for cholesterol management, high doses of two to three grams or more are often used while lower doses are needed for those simply looking to optimize health.

When using niacin pills or a niacin supplement, it’s usually recommended that you take along with a meal so the food can help slow its absorption and prevent niacin side effects like stomach issues.

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 your tolerance to niacin develops.

Additionally, keep in mind that niacin is a water-soluble vitamin, which means that excess levels are excreted through the urine. For this reason, water-soluble vitamins like niacin and other B vitamins must be replenished in the body very frequently through food or supplementation because the body flushes them out almost daily.

How to Take B Vitamins Together

For most people, vitamin B3 can usually be obtained through a healthy diet in high enough amounts to meet your daily needs. However, if you are considering supplementation for a quick and easy way to bump up your intake, be sure to look for a high-quality supplement that is made using whole food sources. Not only does this allow your body to better absorb and utilize these nutrients, but it can also reduce the risk of unwanted vitamin B complex side effects.

Taking a B complex is a great option to ensure you’re meeting your needs for the entire array of B vitamins that your body needs. 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 help optimize digestion and absorption.

B vitamins can be beneficial in supporting metabolism and promoting heart, brain, 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 instead. Try enjoying 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’re getting your daily fix of B vitamins. Unlike supplementation, eating plenty of foods that contain niacin should not result in levels high enough to cause any harmful niacin side effects.

Many other medications, such as Lovastatin and Simvastatin, are often used in combination with prescription niacin to help reduce cholesterol levels and promote heart health. If using these prescription medicines, it’s important to work carefully with your doctor to determine the right dosage for you to minimize side effects and help maximize your results.

Niacin vs. Niacinamide vs. Nicotinamide

Niacin is found in three different forms, including:

  • Nicotinic acid
  • Nicotinamide/niacinamide
  • Inositol hexaniacinate

Nicotinamide, also sometimes called niacinamide, is one of the most common forms of vitamin B3, found in both food and supplement sources. Nicotinamide is often preferred over other supplemental forms of niacin because it’s less likely to cause flushing and can be used for a wide variety of purposes, including treating pellagra, acne and arthritis. However, unlike niacin, nicotinamide is not as effective at lowering cholesterol levels and improving heart health. (22)


Vitamin B3 vs. B12 vs. Other B Vitamins

There are eight B vitamins required by your body, each of which plays a unique role in your health. While vitamin B3 is well-known for its ability to lower cholesterol, reduce inflammation and optimize heart health, vitamin B12 is involved in maintaining the health of the nervous system, synthesizing red blood cells and creating DNA. Meanwhile, other B vitamins help with energy production, liver function, metabolism, growth and development, immune health, and more.

All B vitamins are water-soluble, which means that they dissolve in water and are carried to the tissues of the body but are not able to be stored long-term and require a steady stream in your diet to ensure you’re meeting your needs. They are also often found in similar sources, such as animal products, fortified foods, and select fruits and vegetables. Plus, they all work together in the body to promote proper health, which is why taking a B complex is often recommended over individual B vitamin supplements.


The best way to get more vitamin B3 in your daily diet is by upping your intake of nutrient-rich foods with niacin and being sure to include a few servings per day to help meet your needs. Protein foods like meat, fish and poultry are all excellent sources of niacin, as are other nutrient-rich options like brown rice, sunflower seeds, sweet potatoes and more.

Here are a few delicious and nutritious recipes that can help you take advantage of the multitude of niacin benefits available:

  • Baked Italian Chicken
  • Brown Rice Mushroom Congee with Sardines
  • Paleo Turkey Wonton Soup
  • Sweet Potato Salad with Avocado
  • Chicken Liver Pate


Austrian chemist Hugo Weidel was the first to discover niacin in 1873, and it was later extracted by biochemist Casamir Funk, the same researcher credited with developing the concept of vitamins, or “vitamines,” based on the amine group he noticed in the chemical structure of niacin.

In 1937, Conrad Elvehjem noted that niacin was able to cure pellagra after isolating it from liver, further demonstrating the importance of nutrition on health and disease prevention. The vitamin was soon used to fortify foods in an effort to prevent deficiency and pellagra at the population level. Although it was originally known as “nicotinic acid,” it was later renamed to avoid confusion and dissociate it from nicotine, one of the harmful chemicals found in tobacco products.

By 1955, researchers began recognizing the link between niacin and cholesterol, securing it a slot as one of the oldest lipid-lowering drugs in existence. Today, it’s widely used as a natural remedy for a long list of health conditions, ranging from high cholesterol to schizophrenia and arthritis.


Like other water-soluble vitamins, excess amounts are typically excreted through the urine, helping to prevent niacin toxicity or a niacin overdose. For this reason, eating a wide variety of foods rich in vitamin B3 is unlikely to cause adverse side effects and is generally considered a safe and effective way to meet your needs for this vital vitamin.

However, taking high doses of niacin in supplement form can result in a range of negative symptoms. Niacin flush is one of the most common side effects, which is characterized by redness, burning and itching of the skin. Other potential side effects that can be caused by niacin supplementation include stomach pain, nausea, increased blood sugar, liver damage and gout.

Therefore, it’s absolutely essential to use niacin as directed and consult with your doctor if you have any underlying health conditions or are taking any other medications before starting supplementation. If you do experience any negative symptoms, consider decreasing your dosage or discontinuing use and discussing with your doctor to determine the best options for you.

Final Thoughts

  • What is niacin? Also known as vitamin B3, niacin is a water-soluble vitamin that has been extensively studied for its ability to manage cholesterol levels, maintain metabolism, promote skin health and boost brain function.
  • Found in a variety of food sources as well as supplements and B vitamin complexes, niacin is absolutely essential to many aspects of health.
  • Studies show that niacin can help improve heart health, prevent impotence, relieve joint pain, keep skin clear, regulate blood sugar levels, promote cognitive function, treat pellagra and prevent birth defects. It’s also associated with niacin side effects.
  • Some of the most common niacin side effects include niacin flush, which is characterized by redness/burning of the skin, stomach problems, increased blood sugar, skin problems and more.
  • Enjoy niacin as part of a healthy, well-balanced diet along with a wide variety of other B vitamins to help optimize your health and keep your body at its best.

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