Oxybenzone – and endocrine disruption?

Let’s start with the urine thing.

Every day, we’re exposed to many chemical substances, natural and man-made. This has been the case for thousands of years.

Our bodies are equipped to eliminate many substances to which we are exposed. We primarily do this by metabolising substances in the liver or kidneys, then excreting them from the body—primarily via urine (wee) or faeces (poo).

So, just because a substance is found in your urine doesn’t mean that it has caused you any harm. The authors of the 2008 study didn’t link the widespread presence of oxybenzone in the population, or the levels of oxybenzone found, to any increased risk of adverse health effects.

A 2020 systematic review ‘did not find a strong support for a causal relationship between the systemic level of BP-3 [oxybenzone]…and adverse health outcomes’.⁴ In other words, the amount of oxybenzone in the body was not linked to any negative health effects. 

What’s a systematic review?

A structured and comprehensive literature review that uses explicit, repeatable methods to identify, select and consolidate all available evidence to answer a specific research question.

According to the Cancer Council, ‘there is no evidence of any chemicals approved for use in Australian sunscreens disrupting the endocrine system’.⁵ This includes oxybenzone.

Australia’s regulator of primary sunscreens, the TGA, reviewed the 2001 study and saw no cause for changing how oxybenzone (and the other UV actives) was used in sunscreen. Why?

Let’s start with the in vitro tests, which looked at the effect of oxybenzone on isolated human breast cancer cells. The TGA noted that ‘the UV screens tested were at least 10⁶ times less active than the reference compound’⁶ (oestradiol). The Scientific Committee on Cosmetics and Non-Food Products (SCCNFP) also noted the 10⁶ times lower potency of the UV-filters compared with the positive control, and that in vitro assays 'can only demonstrate whether UV-filters bind on the estrogen receptor or not...they do not provide evidence whether the compounds have estrogenic activity or not'⁷. In other words, they cannot predict effects in people. 

OK, so if the in vitro results weren’t enlightening, what about the in vivo results?

This part of the study has also been criticised. The SCCNFP cited the use of inappropriate rat strains and developmental stage, and the much greater potency of the positive control (ethinylestradiol) than the UV filters.⁷

There was also inconsistency between the findings of the in vitro and in vivo studies in the ranking of the effect of the UV-filters tested.

The SCCNFP concluded that 'Based on the actual scientific knowledge, the SCCNFP is of the opinion that the organic UV-filters used in cosmetic sunscreen products, allowed in the EU market today, have no estrogenic effects that could potentially affect human health.'⁷

Oxybenzone has been studied extensively and its low toxicity is well established. It has been is safe use around the world for decades. Regulators worldwide continually monitor the academic literature for new evidence on chemical ingredients.

Oxybenzone is approved for use in sunscreens by major international regulators, including Australia’s Therapeutic Goods Administration (TGA) and those in Europe, Canada, Japan, Australia, China, Korea, Mexico, Taiwan and Brazil.

For example, in its 2021 Opinion,⁸ the European Commission’s Scientific Committee on Consumer Safety (SCCS) concluded that, ‘the use of BP-3 [oxybenzone] as a UV filter in the following sunscreen products is safe for the consumer’, specifying maximum concentrations of 6% in face cream, hand cream and lipsticks, and 2.2% in body creams, propellant sprays and pump sprays.

Negative claims about oxybenzone are without foundation. Nevertheless, oxybenzone is ‘unjustly criticised by EWG every year’,⁹ continuing to fuel the myth.