Is a Niacin Flush Dangerous for You? Menu Verywell Fit Nutrition Weight Management Nutrition Facts Nutrition Basics Diets Meal Plans Meal Delivery Services View All News Fitness and Nutrition What to Buy How We Test Products Fitness Gear Nutrition Products Tools Recipe Nutrition Calculator Weight Loss Calorie Goal BMI Calculator Body Fat Percentage Calculator Calories Burned by Activity Daily Calories Burned Pace Calculator About Us Editorial Process Meet Our Review Board Search Supplements Is a Niacin Flush Dangerous for You? By Shereen Lehman, MS Shereen Lehman, MS Shereen Lehman, MS, is a healthcare journalist and fact checker. She has co-authored two books for the popular Dummies Series (as Shereen Jegtvig). Learn about our editorial process Updated on September 30, 2022 Fact checked Verywell Fit content is rigorously reviewed by a team of qualified and experienced fact checkers. Fact checkers review articles for factual accuracy, relevance, and timeliness. We rely on the most current and reputable sources, which are cited in the text and listed at the bottom of each article. Content is fact checked after it has been edited and before publication. Learn more. by Sean Blackburn Fact checked by Sean Blackburn Sean is a fact-checker and researcher with experience in sociology and field research. Learn about our editorial process Print While no one needs large doses of niacin, some people take it as a supplement to reduce the risk of heart disease and atherosclerosis. Large daily doses of niacin may help to lower LDL cholesterol (the bad cholesterol) and increase HDL cholesterol (the good form of cholesterol). But, it can have some uncomfortable side effects such as experiencing a niacin flush. Here is what you need to know. Symptoms of a Niacin Flush A niacin flush is a common side effect of taking large doses of niacin (vitamin B3) supplements. The flush happens when the niacin causes the small blood vessels in your skin to dilate so more blood can rush through. It isn't harmful, but it can scare you if you don't know it's coming. Almost everyone who takes large doses of niacin experiences this flush about 30 minutes after taking a large dose (30 to 50 milligrams or more). The flush includes reddening of the skin accompanied by a burning or itching sensation. Flushing of the face is the most common, but it can also occur in the neck and upper body. The flush gets better over time and is usually gone within an hour or two. The niacin flush is generally harmless, but may occasionally be accompanied by a headache, dizziness, or drop in blood pressure. If you experience these symptoms with a niacin flush, you should call your doctor for advice. Prevention You won't get the niacin flush reaction after taking multiple vitamins that contain smaller amounts of niacin. It only happens when you take massive doses. The average adult needs about 14 milligrams per day, so megadoses of individual niacin supplements are far more than anyone needs. To avoid or lessen the niacin flush, you could use time-release forms of niacin, which are absorbed and metabolized slower than regular niacin. Taking a regular aspirin about 30 minutes before taking niacin supplements may also help reduce the discomfort, but probably won't eliminate it altogether. Another alternative is inositol hexanicotinate, which your body converts to niacin. The conversion is slow enough that it doesn't cause a flush in most people. The problem is that you may not get the same lipid-lowering benefit as regular niacin. A 2012 review study reported that inositol hexanicotinate was no better than a placebo for lowering cholesterol levels. Niacin Requirements Along with thiamin, riboflavin, and others, niacin is an essential B-complex vitamin your body needs to convert macronutrients from the food you eat into energy for daily activities. It also helps your digestive system function properly and supports normal skin and nerve function. A niacin deficiency results in a disease called pellagra. People with this condition have digestive problems, inflamed skin, and mental impairments. However, pellagra is very rare and currently, it's only seen in undeveloped countries. The vast majority of people don't need to take niacin supplements because there's plenty of niacin in the foods found in a typical diet, even diets that aren't all that healthy. Nuts, legumes, eggs, poultry, beef, and seafood are all high in niacin, and it's found in smaller amounts in most other foods. So as long as you're eating every day, you're getting plenty of niacin. A Word From Verywell Be careful if you're thinking about taking niacin for your high cholesterol levels. Even though the niacin flush is harmless, large doses of niacin can interact with many different medications. Long-term use can cause liver damage, skin rashes, gastrointestinal problems, and elevated blood sugar. Discuss niacin supplements with your healthcare provider before taking them. 4 Sources Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. National Institutes of Health. Office of Dietary Supplements. Niacin Fact Sheet for Health Professionals. Updated June 3, 2020. Banka SS, Thachil R, Levine A, Lin H, Kaafarani H, Lee J. Randomized controlled trial of different aspirin regimens for reduction of niacin-induced flushing. Am J Health Syst Pharm. 2017;74(12):898-903. doi:10.2146/ajhp160219 MacKay D, Hathcock J, Guarneri E. Niacin: Chemical forms, bioavailability, and health effects. Nutr Rev. 2012;70(6):357‐366. doi:10.1111/j.1753-4887.2012.00479.x National Institutes of Health. Office of Dietary Supplement. Niacin Consumer Guide. Updated July 11, 2019. By Shereen Lehman, MS Shereen Lehman, MS, is a healthcare journalist and fact checker. See Our Editorial Process Meet Our Review Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit Related Articles Niacin Requirements and Dietary Sources The Best Multivitamins for Women of 2022 10 Natural Remedies to Relieve Nausea Can You Really Overdose on Vitamins? 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