The safety of water resistant sunscreens is the focus of a disagreement between consumer review publisher Which? and cosmetics trade association CTPA.
Today, Which? published its annual sunscreen product report, titled: ‘Which sunscreens can you count on?’.
The report made a number of claims regarding the efficacy and safety of sunscreens, especially those that market themselves as water resistant.
Which? explained that these sunscreens are tested by volunteers sitting in tap water baths, not salt or pool water, and that the SPF of a product being tested is permitted to drop by up to 50% before it can no longer be labelled as water resistant.
Taking matters into its own hands, Which? said it recreated a test using chlorinated water and salt water, which showed that two products were not as water resistant in these conditions as they were in the “gently moving tap water”.
Claims rebuked by CTPA
However, CTPA has challenged the report, explaining that the claims could “alarm consumers” and potentially discourage them from using sunscreens.
Director-General Dr Chris Flower, who is also a chartered biologist and toxicologist, said: “The aim of the validated test method used by sun care manufacturers is to determine that the sunscreen will not be completely washed off while being worn in the water.
“Interestingly, tap water is used in the test as it is a more harsh solvent than salt or chlorinated water. To pass the test, a product must retain at least 50% of the initial SPF value after immersion in water.
“In fact an SPF 30 product will stop approximately 96% of UV rays reaching the skin and after robust water resistance testing the product will still filter out at least 93% of the sun’s UV rays.
“Clearly not the dramatic reduction in efficacy that Which? implies. However a non-water-resistant product could be washed off the skin completely meaning no protection from UV rays (until reapplication).”
The CTPA did acknowledge that no product is 100% waterproof and the term ‘sunblock’ should not be used on sun protection products.
Dispelling sun care myths
CTPA also criticised Which?’s sun safety advice, which it described as “outdated”.
Which? stated in the report that the amount of time you take to burn multiplied by the SPF of your sunscreen is the maximum time you should spend in the sun.
For example, if you’d usually burn in ten minutes, Which? claimed an SPF30 product would give you 300min maximum protection.
But CTPA warned that sunscreen should never be used to spend longer in the sun, and that multiplying an SPF figure in this way is “contrary to all the advice given by experts on sun protection”.
It also noted that promoting staying longer in the sun is “extremely irresponsible” and potentially dangerous.
