In the past five months, the US body that regulates sunscreens as over-the-counter drugs, has declared that 12 active ingredients used in these products might not be safe. Four of these ingredients enter the bloodstream through the skin.  None of the commonly used ingredients have been decidedly declared unsafe, but questions hang over them.

In most countries, sunscreens are classified as cosmetic products. In the European Union, they are subject to rules on which ingredients can be used, and must pass tests for skin and eye irritation, for example.   But in the US sunscreens, including cosmetics marketed with a sun protection factor, are now regulated by the FDA like drugs, years after initial introduction in the 1920s. because they make specific claims to reduce the chances of sunburn, skin ageing and skin cancers.

Take oxybenzone, for example, which is widely used in sunscreens. In 2008, the US Centers for Disease Control and Prevention found traces of it in the urine of 97% of the 2500 people it tested. Other studies have found the chemical in breast milk.  It is thought that  oxybenzone might be a hormone disruptor, and act as a very weak oestrogen (so far unsubstantiated).

The FDA issued new proposed rules in February this year, saying that only two of the original 16 “safe” ingredients can actually be considered safe and effective: zinc oxide and titanium dioxide. Of the remaining ingredients, two will be banned, while the rest, including oxybenzone, have big question marks over them. In recent studies, where four such ingredients were tested  (four times a day on the skin, for four days), not only did all four chemicals turn up in the blood, they did so at levels that demand further research to make sure they aren’t causing cancer.  Meanwhile, it was found that. sunscreen was absorbed after the first application and that it persists for days..

The fact is that there is a real lack of information on what the consequences of slathering on suncream are.  Back in the 70s, everyone thought that what you put on the skin stayed there. No one imagined that they  could be absorbed by the skin.

Concerns are now being raised about the chemicals in cosmetics too. They face little regulation in the US and have had the same level of scrutiny as sunscreen in the EU. This means that few studies have been done about which chemicals in cosmetics, if any, can enter the bloodstream and what their effects may be.

Part of the problem comes from complaints falling through the cracks. If someone in the US complains of an adverse drug effect to its manufacturer, then the company has to report it to the FDA. But this isn’t the case for cosmetics. This means that issues can go unnoticed. Notwithstanding this, between 2004 and 2016, “only” 5144 adverse events were reported to the FDA (seems quite a lot to me.  Ed.)   (edited version of a long article in  New Scientist, August 2019)