As far as skin-soothing ingredients go, niacinamide is on just about every list. The antioxidant is a proven anti-inflammatory that helps reduce redness. But can niacinamide ever cause redness? According to a few ironic threads on Reddit, there's a chance you might experience this unlikely side effect.

First, let’s cover why skin-care experts love niacinamide in the first place. "Niacinamide is a version of vitamin B3, which can brighten the complexion, erase wrinkles, reduce water loss through the skin, improve elasticity, and fight inflammation," Perry Romanowski, a cosmetic chemist, tells Allure. "It's a pretty useful ingredient."

But in some cases, niacinamide might actually have an irritating effect. While exploring the skin-care archives on Reddit (as Allure editors do), we noticed an interesting problem popping up in several threads: Niacinamide, the ultra-calming ingredient dermatologists love for its soothing abilities, is being blamed for causing redness and irritation.

In a thread posted to the AsianBeauty subreddit in 2017, one user shared how they had a serious reaction after adding a 5 percent niacinamide serum to their routine. "My face was red, especially my cheeks and nose, and my nose had broken out in a weird, clustered way," they wrote.

After eight months of trying different products, they finally realized the niacinamide was to blame for the redness and irritation. "For some reason, I have a weird, hateful reaction to one of the most effective and common brightening ingredients on the market," they shared. Apparently, this unexpected reaction isn't a fluke.

"I have a sensitivity to niacinamide as well, so know that you are not alone," another Redditor wrote, adding, "There are dozens of us! Dozens!" which was quickly backed up by dozens of comments from the niacinamide sensitive.

This kind of reaction to niacinamide is possible, according to some experts, though very unlikely. "It is very, very rare that I see any irritation from this product," Lily Talakoub, a dermatologist in McLean, Virginia, tells Allure. "In over-the-counter formulas, the concentration is so small it usually doesn't cause a reaction," she explains.

When used in high concentrations, niacinamide can cause skin irritation and redness.

If you happen to be in the unlucky minority who have a bad reaction to a product with niacinamide, there are three primary possibilities: you’re allergic, there's another ingredient causing irritation, or you're using too much.

The first possibility is pretty rare, Joshua Zeichner, a director of cosmetic and clinical dermatology at Mount Sinai Hospital in New York City, tells Allure. More likely, it's another ingredient in the product that's causing the problem. "I have had patients develop skin irritation when using niacinamide-based products, but it likely was one of the preservatives in the product causing the irritation, not the niacinamide itself," Zeichner says.

Another possibility is that you’re overdoing it on niacinamide, according to one expert. "When used in high concentrations, it can cause skin irritation and redness," Talakoub says. "Especially in sensitive areas such as around the eyes."

Exactly how much niacinamide is too much depends on your genes and the sensitivity of your skin, explains cosmetic chemist Perry Romanowski. "There are some people who feel a stinging sensation and those people tend to be more reactive to niacinamide than others," he says.

If you develop any redness, burning, or stinging, you should remove the product from the skin right away.

The good news is that the vast majority of people shouldn't have any problems with this skin-care ingredient. "Niacinamide is generally considered to be such a soothing ingredient that I do not have a conversation with most patients about side effects," says Zeichner. "However, as with any new skin-care product, if you develop any redness, burning, or stinging, you should remove the product from the skin right away."

If you suspect niacinamide might be irritating your skin, talk to your dermatologist about incorporating other redness-fighting ingredients into your routine. Talakoub recommends switching to a product with caffeine and ceramides to address inflammation and redness. "They work better topically for flushing and don't usually have any side effects," she says. Try First Aid Beauty's niacinamide-free Anti-Redness Serum for $36.

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