Ah, summer. That glorious time of year when the sun is out, sleeves are off, and the great hunt for the perfect sunscreen begins. But before you slather yourself or your kids in SPF 50+, here’s your annual reminder: not all sunscreens are created equal.

TL;DR:

Chemical sunscreens may do more than just block UV—they can seep into your bloodstream, sometimes hanging around for weeks. The FDA flagged seven common ingredients (especially oxybenzone and homosalate) in a 2019 study, calling for more safety testing. Some of these chemicals have been linked to hormone disruption and pregnancy risks. Add untested “SPF boosters” to the mix, and you’ve got a messy cocktail. Want a cleaner option? Go with mineral sunscreens like zinc oxide or titanium dioxide—they stay on the surface and out of your system. Parents, especially of kids with vitiligo, should also check out our sun safety guide for children—because sunshine should be fun, not stressful.

 

Chemical Creepers: The Ingredients That Stick Around 

Back in 2020, the FDA decided it was time to investigate what really happens when we apply sunscreen — not just what it does on the skin, but what it might do in the body. The agency published a clinical study in JAMA titled “Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active Ingredients” — and what they found raised a few eyebrows.

Turns out, several commonly used chemical ingredients — like avobenzone, oxybenzone, octocrylene, ecamsule, homosalate, octisalate, and octinoxate — are not content to stay on the skin’s surface. They get absorbed straight through and into the bloodstream. And it doesn’t take weeks of use — some were detectable in blood plasma after just one application.

The worst offenders? Homosalate and oxybenzone.

In the FDA’s study, both remained in the blood above the agency’s safety thresholds for up to 21 days after a single use. Oxybenzone, in particular, has been linked to hormonal disruptions — such as reduced testosterone levels in adolescents — and is considered risky for pregnant women, potentially shortening the length of pregnancy.

Now, it’s worth noting: the FDA didn’t say these ingredients are definitely harmful, but they did raise the red flag and called on manufacturers to conduct further testing to determine long-term safety.

SPF Boosters: The Sneaky Sidekicks

And here’s where things get even more curious. Many sunscreens contain so-called “SPF boosters” — compounds added to increase the product’s sun protection factor. These are labeled “inactive ingredients,” which means they skip safety checks altogether. Yet structurally, they often mimic active substances. Take butyloctyl salicylate, for example — a booster that walks, talks, and acts like an active chemical, but flies under the regulatory radar.

In contrast, old-school mineral sunscreens — those made with zinc oxide and titanium dioxide — don’t absorb into the skin at all. They simply sit on the surface, bouncing UV rays away like tiny reflectors. No hormone drama. No blood absorption. Just good, clean sun-blocking fun.

So as you prep for the summer sun, consider this your nudge to check the label. When in doubt, go mineral. Your skin — and your hormones — will thank you.

In Case You Missed It: Our Pediatric Sun Guide

And while we’re on the topic of sun safety, especially for the little ones: don’t miss our companion piece, "Pediatric Sun Protection Guidelines in Vitiligo: Balancing Sun Safety and Vitamin D." It’s a plain-spoken, parent-friendly guide built from real expert discussions. You’ll find tips on how much sun is too much, the right timing for vitamin D synthesis, and how to align sunscreen use with phototherapy plans.

Because let’s be honest — raising kids with vitiligo (or just pale, curious sun-chasers) is hard enough without chemical mystery ingredients joining the mix.

Continue the journey:

• Pediatric Sun Protection Guidelines In Vitiligo: Balancing Sun Safety and Vitamin D
• Is Sunscreen the New Margarine? 
• FDA’s sunscreen absorption study

Listen to Podcast

• When Spots Start Young (Ep. 34)