The most common sunscreens contain chemical filters. These products usually include a combination of two to six of the following active ingredients: oxybenzone, avobenzone, octisalate, octocrylene, homosalate, and octinoxate. The FDA recently put the whole sunscreen industry on alert by stating that only zinc oxide and titanium dioxide are proven safe. For 12 other ingredients, the FDA has said there isn’t enough data to determine whether they’re safe. Specifically, the FDA raised concerns about the absorption of oxybenzone and its potential effect on hormone levels and the increased absorption susceptibility of children (FDA 2019). Lab tests show that some active ingredients may mimic hormones and physicians have reported sunscreen-related skin allergies, which raises important questions about unintended human health consequences from frequent sunscreen application.

When the FDA began to consider sunscreen safety, it grandfathered in active ingredients from the late 1970s without reviewing the evidence of their potential hazards. In February 2019, the agency released its final draft sunscreens monograph, which contains insufficient health and safety data to designate 12 of the 16 sunscreen filters allowed for use in the U.S. as generally recognized as safe and effective. These 12 ingredients include some of the most commonly used UV filters, including oxybenzone, octinoxate, octisalate, octocrylene, homosalate, and avobenzone. According to the agency, “nearly all of these sunscreen active ingredients … have limited or no data characterizing their absorption.”

Sunscreen is a body care product that consumers are directed to apply a thick coat over large areas of the body and reapply frequently. Thus, ingredients in sunscreen should not be irritating or cause skin allergies and should be able to withstand powerful UV radiation without losing their effectiveness or forming possibly harmful breakdown products. People might inhale ingredients in sunscreen sprays and ingest some of the ingredients they apply to their lips, so ingredients must not be harmful to lungs or internal organs. Furthermore, sunscreens commonly include ingredients that act as “penetration enhancers” to help the product adhere to the skin. As a result, many sunscreen chemicals are absorbed into the body and can be measured in blood, breast milk, and urine samples.