The protection offered by popular water resistant sunscreens plummets in conditions replicating swimming pools, the sea and fast-moving water, Which? has found.
The consumer champion tested water resistance claims made by two popular sunscreens – one own-brand and one well-known international product – and found the sun protection factor (SPF) dropped by up to 59% after forty minutes in salt water.
Water resistance claims are made on the majority of sun protection products, yet Which?’s findings expose serious flaws in the current testing regime – which only requires a volunteer to be immersed in a bath of tap water that circulates to simulate “moderate activity”.
The current tests also allow manufacturers to claim a product is water resistant if the SPF drops by up to 50% after two twenty minute periods of immersion.
Which? carried out more rigorous tests in salt water, chlorinated water and fast-moving water – conditions that more closely resemble those encountered on holiday.
Which? found that the well-known international product’s SPF dropped by 59% after 40 minutes of immersion in salt water and in moving water.
The popular own-branded product’s SPF dropped by 34% in both salt water and chlorinated water. But in reality, sun protection is likely to drop even further – factors such as reflection (from water), heat, light, sweat, towelling and rubbing all reduce the protection of sunscreens.
Which? believes the current requirements around the water-resistance claim are unrealistic to the point of being meaningless. Consumers could rely on a product to provide a level of protection that it is incapable of delivering, putting them at risk in the sun. There’s no way for consumers to know what SPF they’ll end up with after going into the sea or pool when they make a purchase.
Other countries – including Australia and the United States, have stricter requirements where the SPF on the label must be the SPF it provides after immersion in tap water.
In separate tests, Which? looked to see whether 15 widely available sunscreens meet their SPF claims, and all passed.
In 2017, Which? labelled Avon’s Sun+ Multi Protection Moisturising Sun Lotion SPF30 (150ml) a ‘Don’t Buy’ as the product failed the SPF tests. The sunscreen continues to be a ‘Don’t Buy’ this year as it has not been reformulated and is still available to buy.
Nikki Stopford, Which Director of Research and Publishing, said: “Our research shows water resistant sunscreens don’t live up to their claims when subjected to rigorous tests – raising serious questions about the current guidelines.
“With 15,400 new cases of melanoma each year, manufacturers should be required to robustly test their products and make only claims that can be relied on, ensuring holidaymakers know they can trust their sunscreen to protect them.”
However, Dr Chris Flower, director-general of the Cosmetic, Toiletry and Perfumery Association (CTPA) told the BBC that Which?'s findings were flawed and consumers should have confidence in water-resistant sunscreens.
"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," he said.
"This is clearly not the dramatic reduction in efficacy that Which? implies."