Is niacinamide safe during pregnancy?

What does the evidence say about niacinamide during pregnancy?

1. Nicotinamide, the form of vitamin B3 used in most niacinamide skincare, doesn't cause the skin flushing that the other common form of the vitamin, nicotinic acid, can cause. 1
2. Pregnant adults need about 18 mg of niacin a day, a bit more than non-pregnant adults, and shouldn't exceed 30 mg a day from supplements or fortified food, a limit built around what you swallow, not what a topical serum delivers. 1
3. Of the two main supplement forms of niacin, nicotinamide causes fewer side effects than nicotinic acid at similar doses. 2
4. When researchers gave pregnant and non-pregnant volunteers the same oral dose of nicotinamide, their bodies processed the compound itself the same way, with pregnancy only slightly speeding up how fast the kidneys cleared one breakdown product. 3
5. A review of skincare safety in pregnancy found that most topical products for common skin complaints act locally with minimal absorption into the body, flagging only hydroquinone and tretinoin for extra caution, not niacinamide. 4

Is niacinamide safe in each trimester?

• First trimester. Hormonal skin changes, including early dark patches, often start showing up now, which is when people start looking for a brightening ingredient without retinoid-style risk. Niacinamide doesn't carry that risk. It's not on the short list of ingredients, hydroquinone and tretinoin, that pregnancy skincare reviews flag for extra caution, so most people can start or keep using it. Patch test any new product, and mention your skincare routine at your first prenatal visit.
• Second trimester. Pregnancy-related dark patches, sometimes called the mask of pregnancy, often get more noticeable now, which is when niacinamide's tone-evening reputation gets the most use. The safety picture doesn't change from trimester to trimester: niacinamide keeps working locally on the skin instead of building up in your body. Daily sunscreen matters more than any single serum, since sun exposure, not a skincare ingredient, is the main driver of these dark patches.
• Third trimester. Guidance stays the same now. There's no known trimester-specific window of concern for topical niacinamide, unlike oral isotretinoin or other high-dose exposures taken by mouth. One 2024 study found pregnant volunteers cleared a breakdown product of nicotinamide a bit faster than non-pregnant volunteers, which researchers called a metabolic difference, not a safety concern, and it barely applies to a topical product anyway. If you're also taking a prenatal vitamin or B-complex supplement, mention your full routine to your provider so nothing gets double-counted.