In 2021, the US FDA declared zinc oxide and titanium dioxide to be the only UV filters that are generally recognized as safe and effective (GRASE). That doesn't mean the others are not safe, but let's dive into the details.

In the same paper, the FDA declared sunscreens containing aminobenzoic acid (PABA) and trolamine salicylate Not GRASE Due to Data Showing Safety Issues. 

The remaining UV filters approved for use in the US, including oxybenzone, avobenzone, octinoxate, octisalate, homosalate and octocrylene, have been deemed Not GRASE Due to Insufficient Data.

Things to note

The US FDA hasn't approved a new UV filter for use in 23 years... and of course the technology has advanced significantly since then. There are a number of chemical UV filters approved in the EU, Australia and New Zealand that do have good safety records so far.

Credit to Skinnies Sungel and Oasis Sun Feel-Dry Sport and Ultra for using only these new filters. Unfortunately these are the only chemical sunscreen products we've found that don't include at least one of the older UV filters. (Skinnies' other products, including their Conquer and Kids sunscreens, and Oasis Sun's original Healthy Family formula all use Octocrylene.)

The categorisation "Not GRASE Due to Insufficient Data" doesn't mean these UV filters are not safe. They are still approved for use. However, it does mean there is enough research out there to raise questions.

In the FDA's words

"In recent years, a growing body of data has suggested that the transdermal absorption of some sunscreen active ingredients is greater than previously thought, and thus may raise previously unevaluated safety concerns, including the potential for reproductive, developmental, or carcinogenic effects."

The research

Oxybenzone, which is also used in perfumes, lipsticks, hair sprays and conditioners, has been found in human breast milk, amniotic fluid, urine, and blood plasma. High levels of oxybenzone have been associated with changes in birth weights (Janjua et al 2004), indicating potential endocrine effects. Children under two are less able to metabolize oxybenzone, meaning it can accumulate in their bodies. As a result, the FDA is working to determine whether sunscreen products containing oxybenzone should be contraindicated for use in children younger than 2 years, particularly given that zinc oxide and titanium dioxide are readily available for use and "do not raise the same questions about safe use in young children."

While most studies have focused on oxybenzone, a number of studies have examined other chemical UV filters' potential effects on our endocrine system. As noted by the FDA, homosalate and padimate O have also shown hormonal effects in mammalian assays (animal testing), while homosalate, octinoxate and octocrylene have shown endocrine effects in in vitro and in vivo assays (lab studies).

The good news

Zinc oxide and titanium dioxide have been found to be not only safe, but effective. The FDA notes that there is "substantial evidence that zinc oxide... does not penetrate into or through human skin to any great extent and, to the extent any de minimis penetration occurs, does not result in adverse health effects." Moreover, when used as directed, zinc oxide not only prevents UVB rays from damaging our skin, but protects us against UVA rays as well.

That sounds GRASE to us!

Sources: 

Proposed Administrative Order OTC000008_Amending M020_Sunscreen_Signed24Sept2021.pdf (fda.gov)

Questions and Answers: FDA posts deemed final order and proposed order for over-the-counter sunscreen | FDA