Is It Safe to Use Sunscreen on Babies Under Six Months?

I’m curious why there is a recommendation to avoid sunscreen in babies under six months old. It seems that most sources (including the FDA!) state that zinc-oxide-based mineral sunscreens shouldn’t be used under six months due to a risk of skin irritation or rashes. However, zinc oxide is the primary ingredient in most diaper-rash creams, which are fine (I think?) to use from day one. Is this an antiquated recommendation, or is sunscreen really more dangerous than sunburn in babies less than six months old?
—Melissa

Sunscreen recommendations are confusing and vague. For babies under six months, the FDA recommends using none, whereas the American Academy of Pediatrics says only on “small areas.” Over six months, it’s open season. The concerns primarily relate to rashes and irritation. As kids age, their skin gets less sensitive. But there is no sharp age cutoff. Five and a half months and six months are not wildly different. There’s also a lot of variation across people. Some kids get more rashes than others after sunscreen, even within the same age group. If you’re looking for some study that definitively analyzes age-based sunscreen reactions, you will not find it.

Having said this: sunscreen is imperfect. Shade, or UV-protective clothing, is much better. One difference between smaller and bigger babies is that because little babies are less mobile, it’s often easier to keep them shaded and dressed. If you can keep your baby in the shade, wearing an adorable hat and a long-sleeved bathing suit, that’s a better option than sunscreen, even if they’re older.This all suggests to me a more nuanced approach, closer to the AAP than the FDA. First best is to keep your baby out of the sun. But if they do need to be in the sun, it’s okay to use a bit of sunscreen on the exposed parts — face, hands, feet. And this goes for below and above six months.