The Gander 27 May 2019

The Medical Independent blog takes a look at the more unconventional niches in science and research

Here’s the rub on sunscreen toxins

A small-scale study has found that when sunscreen creams are used regularly, even for one day of frequent use, their active ingredients are absorbed into the user’s bloodstream at levels that indicate the need for toxicology testing.

This year, the US Food and Drug Administration (FDA) put forward a new guideline which stated that any active ingredient from over-the-counter sunscreens absorbed into the bloodstream at concentrations greater than 0.5ng/mL should indicate the need for toxicology testing in the user. However, the trial, which was published recently in JAMA, showed that four active ingredients in the cream were all absorbed into the blood at levels higher than recommended.

While the authors explained that there was no direct proof that the four active ingredients — ecamsule, octocrylene, oxybenzone and avobenzone — caused any harm to a user, they were detected at high concentrations among the 24 healthy trial participants who used the cream four times per day for four days on 75 per cent of their bodies.

All four ingredients exceeded the FDA-recommended absorption rates after just one day of use, said the study authors. Absorption rates varied according to product but avobenzone, for example, was absorbed at a range between 1.8ng/mL and 4.8ng/mL. Previous research has linked oxybenzone, which was identified in the users’ bloodstreams at concentrations of over 200ng/mL, with hormonal changes in boys and men.

The authors stressed that while they could not pinpoint any adverse physical effects in the participants, there is a need for sunscreen manufacturers to conduct further studies to assess any potential risks.