Since they’re so beloved in skin care, you may be wondering: Can you use niacinamide and vitamin C together? Or are the two formulas more like frenemies—seemingly tolerable but way too competitive to ever have a meaningful relationship? Ahead, experts weigh in. Here’s where things get hairy: Older research has shown that mixing vitamin C—specifically the unstable ascorbic acid—with niacinamide can convert it to the compound niacin, which can cause flushing (think blotchy, inflamed skin). However, the science may be a bit overstated: It actually takes extremely high heat for the two ingredients to convert to niacin, which is unlikely to happen in skin care formulations. That older study used nonstabilized forms of both ingredients in a high-temperature environment—one that did not represent typical skin care products in development, manufacturing, or in real-world storage and usage. If you’re at all worried, though, many experts (including board-certified internist and holistic skin care expert Zion Ko Lamm, M.D., in a TikTok video) advise to proceed with caution when layering the two ingredients, especially if your skin is already sensitive to niacinamide itself. The bottom line? It is possible that combining niacinamide and vitamin C can convert to niacin and cause flushing, but it would need to be exposed to a super-high heat to get to that point. Skin care formulations don’t tend to reach those levels of heat, so you should be just fine—but if your skin falls more on the sensitive side, you might still want to proceed with caution. And if you do have sensitive skin, you might want to use low concentrations of niacinamide, typically no greater than 2%, to avoid irritation. Although, you should always apply your skin care products from thinnest to thickest: So, say, if you have a niacinamide serum and a vitamin-C-infused moisturizer, apply the serum first, then follow up with the cream. Since niacinamide pairs so well with other ingredients (unlike vitamin C), you may be better off sticking to a pure vitamin C serum, then following up with a hydrating moisturizer that contains niacinamide—you won’t have to worry about the niacinamide not doing its job since it’s pretty stable overall.
