Niacin Flush vs. No Flush: What’s the Difference?

When you take a high-dose niacin (vitamin B3) supplement, you may have noticed that you turn as red as a beet and warm as the sun. That's known as the niacin flush, and it can be startling and uncomfortable, especially if you're not expecting it.

But this side effect is actually harmless! Plus, taking vitamin B3 in high doses may help promote your health in a variety of ways, particularly for maintaining already-healthy cholesterol levels.

Let's dive right in to learn more about niacin and niacin-induced skin flushing!

What causes a niacin flush?

Vitamin B3 reacts with specific proteins in the skin and increases prostaglandins, a group of specialized compounds the body makes from fat that exert hormone-like effects, causing blood vessel dilation. As your blood vessels dilate, flushing spreads through your face and progresses to your arms and chest. This tingling may feel odd, but it's to be expected as part of a niacin-induced flush.

How long does a niacin flush last?

The discomfort will usually start within 30 minutes after you take vitamin B3 and may last up to an hour—but everyone is different, so your experience may vary. The good news is that most people will eventually build up a tolerance and the flushing will stop over time.

Do all niacin supplements cause a flush?

No. Taking straight niacin (nicotinic acid), especially in high doses, can result in a niacin flush. But other forms of niacin, such as nicotinamide and inositol hexanicotinate, do not cause a flush. However, inositol hexanicotinate and nicotinamide are less effective in supporting healthy cholesterol levels.

So if you're looking for lipid (aka cholesterol) management support, and you can stand the flush (or want to experience it for some reason), go for niacin!

Pro tip: Lab tests can give you an idea of how your body is responding to niacin, so you can see which option works best to support your health.

What is niacin?

Niacin, or nicotinic acid, is a B vitamin, specifically vitamin B3. Your body needs this vitamin to perform hundreds of essential functions!

If you've been working on maintaining already-healthy cholesterol levels, and you haven't seen the results you were expecting, your doctor may recommend you take niacin in high doses. Not only is niacin a superstar at supporting cholesterol already within a healthy range, it's also good for your whole-body health. After all, every cell in your body uses vitamin B3 for every task that requires energy, aka everything your body does!

Like other B vitamins, niacin is a water-soluble vitamin and must be obtained through food or a supplement. But while there are food sources of niacin, sometimes the best way to ensure your body is getting enough quantities is through dietary supplements.

Vitamin B3 is found naturally in various foods, including:

• Whole grains
• Legumes
• Fatty fish
• Poultry
• Eggs
• Milk
• Avocados
• Organ meats
• Peanuts

Niacin helps convert the foods you consume into energy. Specifically, your body uses niacin to produce the coenzyme nicotinamide adenine dinucleotide (NAD). This coenzyme helps in the conversion of different types of food nutrients like carbs, fats and protein to turn them into energy your body can use. NAD is required by over 400 enzymes in the body! Pro tip: Your body can also convert tryptophan (an amino acid in your Thanksgiving turkey) into niacin with the help of vitamins B2 and B6 as well as iron. So now you have an excuse to go for seconds!

If this little miracle nutrient's job of turning food into energy and maintaining cholesterol already within a healthy range wasn't enough, nicotinic acid also helps support DNA health and the body's antioxidant activities.

Are there benefits to a niacin flush?

Niacin flushing indicates your body is receiving a large amount of vitamin B3. The flush means that blood vessels are dilating and increasing blood flow, which can be unpleasant but temporary.

In high doses, niacin also supports already-healthy cholesterol levels. It helps regulate the healthy ratio between low-density lipoproteins (LDL) and high-density lipoproteins (HDL). Research has shown that high-dose nicotinic acid, at amounts that may cause flushing in some people, may help promote balance in already-healthy HDL and LDL cholesterol levels.

So, the next time you feel the warmth of your skin and you look as if you've run a marathon after you take your nicotinic acid, remember all the good it is doing for your body and try to embrace the discomfort—it's only temporary!

Of course, check with your doctor first before using any supplement and ensure they are on board with you taking the flush-causing niacin.

Should I take no-flush niacin?

It's better to take flush niacin if you are seeking benefits such as regulating already-healthy HDL and LDL cholesterol levels because no-flush niacin does not reliably have the same effects on lipids and cholesterol. If you really can't tolerate the flush, or your main goal is not to target lipids (fats), flush-free niacin is a good option. Both inositol hexanicotinate and niacinamide (nicotinamide) are flush-free.

Pro tip: You can take a quiz to get personalized supplement recommendations to manage cholesterol.

4 ways to reduce niacin flushes

You can reduce the flush response, even if you're not able to prevent it entirely. Here's how:

• Gradually work to a high dose

  : Start with a low dose of niacin and slowly increase the amount over time. This may help you adjust to the niacin flush so that it is not as unpleasant. For example, you can take 100 mg of niacin twice daily, then double the amount each week until you reach the recommended dose.

• Take it with food

  : Although niacin is water-soluble, eating an apple or taking niacin in the morning right after breakfast can help slow down niacin absorption, easing the intensity of a niacin flush.

• Avoid hot showers

  : Taking a hot shower or bath immediately after taking niacin only increases the effects of a niacin flush. The hot water also causes the vessels in your skin to dilate.

• Skip the coffee (and the soup)

  : Hot beverages can make the flushing worse as well, so if you need your morning java, take your niacin later in the day.

Everyone is different, so people may require different doses of vitamin B3 based on their specific needs. Absorbability can also vary significantly depending on the form of niacin you use.

Bottom line: Niacin supplements can be very safe, even in large doses that cause flushing. However, speaking with your doctor to determine the best dose and form for your healthcare needs is always a good idea.

References

• Jacobson TA. "A "hot" topic in dyslipidemia management—"how to beat a flush": optimizing niacin tolerability to promote long-term treatment adherence and coronary disease prevention." Mayo Clin Proc. April 2010. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2848425/
• Kamanna VS, et al. "The Mechanism and Mitigation of Niacin-Induced Flushing." Int J Clin Pract. September 2009. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2779993/
• Morabia A. "Joseph Goldberger's research on the prevention of pellagra." J R Soc Med. November 2008. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2586852/
• "Niacin." National Institutes of Health. March 2021. https://ods.od.nih.gov/factsheets/Niacin-Consumer/
• "Niacin." Oregon State University. August 2018. https://lpi.oregonstate.edu/mic/vitamins/niacin