Takeaways
- Niacin can cause flushing, a common but harmless side effect
- High doses may lead to liver damage and blood sugar changes
- Different niacin forms have varying side effect profiles
- Proper dosing and medical supervision reduce risk of side effects
- Some people experience digestive issues when taking niacin
- Alternatives exist for those who can’t tolerate niacin supplements
Understanding Niacin
Niacin, also called vitamin B3, is important for many body functions. It helps with energy production and the repair of DNA.[1] Many people choose to take niacin supplements to support their health.
Niacin supplements are available in different forms, including nicotinic acid, niacinamide, and inositol hexanicotinate.[2] Each form affects the body differently and can cause varying side effects.
Doctors often prescribe niacin to help manage cholesterol levels. It can increase “good” HDL cholesterol and lower triglyceride levels.[3] Niacin may also be used to support skin health or cognitive function.
Common Niacin Side Effects
Flushing
The most common side effect of taking niacin is the ‘niacin flush’. This reaction causes redness, warmth, and tingling, particularly on the face and upper body.[4]
Niacin flush happens when blood vessels near the skin’s surface widen.[5] Typically, this effect starts within 30 minutes of taking niacin and may last for about an hour.[6]
Immediate-release niacin often results in more intense flushing compared to extended-release forms.[7] However, extended-release niacin might carry a greater risk of liver issues.[8]
Gastrointestinal Issues
Some people experience digestive problems when taking niacin. These issues can range from minor discomfort to more noticeable symptoms.[9]
Higher doses of niacin increase the likelihood of gastrointestinal side effects.[10] Individuals with sensitive stomachs might be more prone to these issues.
Common gastrointestinal symptoms from niacin may include upset stomach, nausea, bloating, gas, and diarrhea.[11]
- Nausea
- Stomach pain
- Diarrhea
- Bloating
- Indigestion
Skin Reactions
In addition to flushing, niacin can cause other skin-related side effects. These reactions might be more bothersome than the typical niacin flush.[12]
Some individuals may experience itching or rashes when taking niacin supplements.[13] More serious skin reactions are possible, although uncommon.
Skin issues from niacin are generally mild and resolve on their own. However, it’s advisable to see a doctor for persistent or severe reactions.
Severe Niacin Side Effects
Liver Damage
Large doses of niacin can impact liver function. This is more likely with extended-release niacin.[14]
Signs of liver damage may include jaundice (yellowing of the skin or eyes), dark urine, abdominal pain, and fatigue.[15]
- Yellowing of the skin or eyes
- Dark urine
- Upper right abdominal pain
- Unusual fatigue
Regular blood tests can help monitor liver health in people taking high doses of niacin. Early identification of problems allows for prompt intervention.
Blood Sugar Irregularities
Niacin can affect blood sugar levels, especially at higher doses. This is a concern for those with diabetes or prediabetes.[16]
Niacin may temporarily raise blood sugar.[17] It can also contribute to insulin resistance in some people over time.[18]
People with diabetes should carefully monitor their blood sugar while taking niacin. Adjustments to their diabetes medication may be needed.
Niacin Form | Dose | Effect on Blood Sugar |
---|---|---|
Immediate-release | Low (50-100 mg) | Minimal impact |
Immediate-release | High (1000+ mg) | May increase blood sugar |
Extended-release | Low (500 mg) | Minimal impact |
Extended-release | High (1500+ mg) | May increase blood sugar |
Other Serious Side Effects
Although less common, niacin can cause other significant side effects. These are more likely with high doses or prolonged use.
Rare but serious side effects of niacin include irregular heartbeat, severe allergic reactions, and gout.[19]
- Irregular heartbeat
- Muscle damage
- Gout flare-ups
- Stomach ulcers
- Vision problems
Medical supervision is important when using high-dose niacin. Regular check-ups and blood tests can aid in detecting potential problems early on.
Factors Influencing Niacin Side Effects
Dosage
The amount of niacin taken directly impacts the risk of side effects. Higher doses generally result in more side effects.[20]
Low doses of niacin (50-100 mg) rarely cause issues.[21] Moderate doses (500-1000 mg) might cause flushing and mild effects.[22] High doses (1500+ mg) increase the risk of more severe effects.[23]
Niacin Dose | Common Side Effects | Risk of Severe Side Effects |
---|---|---|
Low (50-100 mg) | Mild flushing | Very low |
Moderate (500-1000 mg) | Flushing, mild digestive issues | Low |
High (1500+ mg) | Intense flushing, digestive problems | Moderate to high |
Formulation
Different forms of niacin supplements have unique side effect profiles. The main types include immediate-release, extended-release, and no-flush niacin.
Immediate-release niacin tends to cause the most intense flushing.[24] However, it might have a lower risk of liver problems than extended-release forms.
Extended-release niacin causes less flushing but may have a higher likelihood of causing liver problems.[25] No-flush niacin (inositol hexanicotinate) tends to cause fewer side effects but may be less effective.[26]
Individual Factors
How an individual reacts to niacin can vary. Some people are simply more sensitive to its effects.
Factors that can make someone more susceptible to niacin side effects include having sensitive skin, pre-existing liver conditions, and diabetes.[27]
- Age (older adults may be more sensitive)
- Liver or kidney problems
- Diabetes or prediabetes
- History of stomach ulcers
- Alcohol consumption
It’s important to consider your health before starting niacin. Discuss the potential risks with your doctor, particularly if you have pre-existing health conditions.
Managing Niacin Side Effects
Prevention Strategies
Taking steps to minimize side effects can make niacin supplementation more tolerable. Many people have found these strategies helpful in reducing discomfort.
Gradually increasing the dose can allow your body to adapt to niacin.[28] Start with a low dose and slowly increase to your target amount over several weeks.
Steps to reduce the risk of niacin side effects include taking it with food, starting with a low dose, and using an extended-release form.[29]
- Take niacin with food
- Avoid hot drinks or alcohol when taking niacin
- Use extended-release forms for less flushing
- Take an aspirin 30 minutes before niacin
- Stay hydrated
Treatment Options
If side effects occur, several treatments can help reduce discomfort. Most niacin side effects are manageable with simple solutions.
Over-the-counter pain relievers can help with flushing and headaches.[30] Anti-diarrheal medications may be useful for digestive problems.
Common remedies for managing niacin-induced discomfort include taking aspirin before niacin, using cool compresses for flushing, and consuming food with the supplement.[31]
- Cool compresses for skin flushing
- Ginger tea for nausea
- Antacids for heartburn
- Antihistamines for itching
- Increased fluid intake
Niacin Interactions
Medications
Niacin can interact with various medications. These interactions might increase side effects or alter how well either substance works.
It’s important to understand potential interactions to ensure safe niacin use. Always tell your doctor about all the medications and supplements you are using.
Common medications that may interact with niacin include blood pressure medications, cholesterol-lowering drugs, and some diabetes medications.[32]
- Statins (cholesterol-lowering drugs)
- Blood pressure medications
- Aspirin and other blood thinners
- Diabetes medications
- Zinc supplements
Supplements and Foods
Certain supplements and foods can impact how niacin functions in the body. These interactions may either enhance or diminish its effects.
Being aware of these interactions can help you make informed decisions about your diet and supplement choices.
Substance | Interaction with Niacin | Effect |
---|---|---|
Alcohol | Increases flushing | Enhanced side effects |
Caffeine | May reduce absorption | Decreased effectiveness |
Vitamin C | May enhance effects | Potentially beneficial |
Fish oil | Similar effects on cholesterol | May be complementary |
Green tea | May affect liver enzymes | Potential for liver stress |
When to Seek Medical Help
Knowing when to seek medical attention for niacin side effects is important. Most are mild, but some can indicate serious issues.
Severe or persistent side effects require immediate medical evaluation.[33] Early intervention can help prevent complications from niacin use.
If you experience concerning side effects from niacin, discontinue use and see a doctor as soon as possible.
- Stop taking niacin immediately
- Contact your healthcare provider
- Describe your symptoms in detail
- Follow medical advice promptly
- Schedule follow-up tests if recommended
Alternatives to Niacin Supplementation
For those who can’t tolerate niacin supplements, alternatives do exist. These options might provide similar benefits but with fewer side effects.
Dietary changes can increase your natural niacin intake. Other supplements or medications may also be appropriate based on individual health goals.
Natural sources of niacin include meat, poultry, fish, peanuts, and fortified grains.[34] These can help support overall health.
- Chicken breast
- Tuna
- Avocados
- Peanuts
- Whole grains
FAQ: People Also Ask
Niacin supplements can offer health benefits, but they also carry potential side effects. Understanding these effects allows you to make well-informed decisions. Always consult a healthcare provider before starting any new supplement, especially if you have existing health problems or take other medications. Regular check-ins and open communication with your doctor ensure safe and effective niacin use. By staying informed and observing your body’s response, you can maximize niacin’s benefits while minimizing risks. While niacin can be beneficial for some, it’s not suitable for everyone. Exploring other options and considering your individual needs will help you make the best health decisions.What is niacin flush and is it dangerous?
How long do niacin side effects last?
Can niacin cause weight gain?
Is it safe to take niacin daily?
What’s the difference between regular niacin and no-flush niacin?
Can niacin interact with my medications?
Are there any long-term side effects of taking niacin?
How much niacin is too much?
Niacin is a precursor to two coenzymes, NAD and NADP, which are essential in metabolic processes including energy production, DNA repair, and cell signaling.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
These three forms of niacin differ in their chemical structure and how they are metabolized by the body, which can lead to differences in effectiveness and side effects.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Niacin has been shown to increase HDL cholesterol, decrease LDL cholesterol, and lower triglycerides, though it is less frequently used due to side effects compared to other cholesterol medications.
Source: “Niacin‐ER/Statin Combination for the Treatment of Dyslipidemia: Focus on Low High‐Density Lipoprotein Cholesterol” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8109479/
Niacin flush is caused by the release of prostaglandins, leading to vasodilation. This side effect is typically harmless but can be uncomfortable.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
The widening of the blood vessels (vasodilation) is a physiological response to prostaglandins released by niacin and causes increased blood flow to the surface of the skin, resulting in the flush.
Source: “Inhibition of soluble epoxide hydrolase limits niacin-induced vasodilation in mice” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3396292/
The onset and duration of the niacin flush can vary slightly from person to person, but this is the general time frame.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
The rapid release of niacin into the bloodstream with immediate-release forms causes a more significant and rapid vasodilation compared to extended-release forms, which release more slowly.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
The sustained release of niacin in extended-release forms may put more stress on the liver, thus increasing the risk of liver damage compared to immediate-release forms.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Niacin can cause GI symptoms due to various factors like increased stomach acidity, and irritation of the digestive tract.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
The increased dosage and its effect on the digestive tract can increase the chances and severity of gastrointestinal side effects.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
These symptoms occur due to irritation and changes in the digestive system’s function in response to niacin supplementation, especially at higher doses.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Other skin reactions like itching or rashes can result from taking niacin, though they are generally less common than flushing.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
These skin reactions are likely due to histamine release, other immunological response, or inflammatory reactions in the skin.
Source: “Effect of Two Aspirin Pretreatment Regimens on Niacin-Induced Cutaneous Reactions” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1497169/
The sustained release of niacin can create a prolonged stress on the liver, potentially leading to damage over time, especially with elevated doses.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
These symptoms arise when the liver is not functioning properly to process bilirubin or detoxify the body, and can be indicative of serious liver issues.
Source: “Synergistic and Detrimental Effects of Alcohol Intake on Progression of Liver Steatosis” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8910376/
Niacin can cause insulin resistance and increased glucose production by the liver, thus raising blood sugar levels, which is a concern for people with diabetes or insulin resistance.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
The blood sugar raising effects of niacin are generally temporary and often reversible upon discontinuation, but these effects can be of greater concern to people with diabetes or pre-diabetes.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Insulin resistance can develop with chronic niacin use due to niacin’s effect on glucose metabolism, which can lead to higher blood sugar levels and an increased risk of type 2 diabetes.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Niacin can affect various systems, and while rare, these serious side effects may occur, especially at high doses.
Source: “Long-term safety and efficacy of triple combination ezetimibe/simvastatin plus extended-release niacin in patients with hyperlipidemia” https://pubmed.ncbi.nlm.nih.gov/20152243/
The body’s physiological response to niacin is dose-dependent. With higher dosages, the effects are more pronounced, including both positive and negative effects.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Low doses of niacin are generally associated with a lower risk of significant side effects, especially when taken with food.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Moderate doses of niacin are more likely to cause side effects like the niacin flush, and mild stomach discomfort, though severity can vary among individuals.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
High doses of niacin pose greater risk for serious side effects, including more severe GI issues, liver damage, and other complications, which necessitate medical supervision when using these doses.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Immediate release formulation leads to a quick and large surge of niacin into the blood stream, causing a greater and more rapid vasodilation and thus more intense flushing.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
The sustained release of niacin in these formulations can reduce the flushing but may place a longer stress on liver function, increasing risk for liver damage.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
No-flush niacin does not produce flushing due to it not being readily converted to nicotinic acid in the body. This may also limit its effectiveness at some niacin benefits.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Individuals with sensitive skin are more prone to skin reactions like flushing, those with liver conditions are less able to handle processing niacin, and people with diabetes are more susceptible to the negative effects niacin has on blood sugar.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Starting at lower doses allows the body to adjust to the presence of niacin before increasing to higher amounts, helping to avoid sudden and severe side effects.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Taking with food can slow absorption of niacin, and taking an extended-release form can similarly reduce flushing. Starting with a low dose and gradually increasing it can allow the body to adjust.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin can help manage flushing by blocking the production of prostaglandins, and can also help alleviate headaches caused by vasodilation.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Taking aspirin before niacin helps reduce the prostaglandin response; cool compresses constrict the blood vessels in the skin, and taking niacin with food can slow down absorption
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Niacin can alter the effects of blood pressure medications, enhance side effects of certain cholesterol-lowering drugs, and interfere with glucose control in patients using diabetes medications.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Severe or prolonged side effects indicate a potentially serious issue with niacin supplementation and should be evaluated by a healthcare provider.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
These foods either naturally contain niacin or have it added during processing, and can be included in a regular diet for niacin intake.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Niacin flush is due to vasodilation and while usually not dangerous, the sensation can be very uncomfortable for some individuals.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
The rapid onset and offset of niacin flush is a result of the body quickly metabolizing niacin.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
While niacin can affect blood sugar, there is no evidence directly linking niacin to weight gain.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Daily use requires proper dosing and monitoring as prolonged high doses can create adverse effects.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
The flushing caused by nicotinic acid is a well-known side effect, and this form of niacin is generally used in research, because of its greater effect on the lipid panel, when compared to no-flush forms.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
The lack of flushing from this form of niacin is due to how it is metabolized, which may impact it’s effectiveness for some purposes, including cholesterol management.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Niacin has been shown to have interactions with statin medications, blood pressure drugs, and can impact blood sugar, which will have implications for individuals on diabetes medications.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
Long term use of high dose niacin can cause damage to the liver, can lead to hyperglycemia, and can lead to the formation of ulcers in the stomach.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/
The upper limit (UL) of 35 mg per day refers to supplemental doses. Therapeutic doses used to treat conditions like hypercholesterolemia may be much higher, as directed by a doctor.
Source: “The Promise of Niacin in Neurology” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457276/