Three popular sunscreen lotions offer less protection than they claim, according to consumer organisation Which?

In spot checks on 26 sunscreens – including some cheaper options from supermarkets Aldi and Lidl – lotions from Calypso Sun, Bondi Sands and Asda failed to pass all the tests.

Asda questioned the validity of the Which? tests, saying independent tests of the same batch had confirmed the lotion provided the level of protection on the label.

Calypso Sun said all products were carefully tested and passed European Union standards.

Which? says these products failed some of its checks:

• Calypso Sun Press & Protect Sun Lotion SPF30
• Asda Protect Moisturising Sun Lotion SPF 30 High
• Bondi Sands SPF 50+ Face Sunscreen Lotion

Lotions that passed the tests included:

• Lidl Cien Sun Spray SPF 30
• Aldi Lacura SP 30 Sun Lotion
• Nivea Sun Protect & Moisture Lotion SP 30
• Boots Soltan Protect & Moisture spray SPF30
• Garnier Ambre Solaire Kids Water Resistant Sun Cream Spray SPF50

Natalie Hitchins, at Which?, said: “It is incredibly concerning that some big brands failed our tests and did not offer the level of sun protection claimed on the packaging.

“However, it is great to see cheaper top-quality sunscreen options available on the High Street and in supermarkets at a time where shoppers need affordable options.

“Our results prove that there’s no need to splash out to keep you and your loved ones safe in the sun this summer and that many of the supermarket own-brand products can do a good job.”

Which? tested how much energy it took to redden the backs of volunteers exposed to rays from ultraviolet (UV) lamps, with and without sunscreen, and applied the lotions to glass plates to measure the amount of light they filtered.

It carried out some tests in 2023 and some in 2024.

An Asda spokesperson told BBC News: “We recently had ourAsda Protect Moisturising Sun Lotion SPF 30 High retested by a leading external provider using internationally recognised testing methods.

“These test results confirmed that this product has a sun-protection factor of 31.5 – and therefore, we do not recognise the test results Which? has published.

“When Which? reviewed this same product in 2022, they awarded it ‘great value’ at that time and it passed their SPF test.

“The product formulation has not changed since then, so we would question the validity of their test.”

A spokesperson from Calypso Sun told BBC News: “We would like to thank Which? for sharing their 2024 study results – however, all our products are carefully and independently tested and have passed, in accordance with EU standards and regulations.

“Calypso Sun will continue its proud commitment in providing safe-sun protection products for all the family, a promise we have consistently kept over several decades.”

BBC News has tried to contact Bondi Sands.

Cosmetic Toiletry and Perfumery Association director Dr Emma Meredith said: “An incredible amount of research goes into developing and testing sunscreens to make sure we can trust the protection that they offer.

“Companies use supportive data and scientists with expert sun-care knowledge to check their results and should only sell the product when the whole package of development test data and the final sun-protection test results match.”

Prof Dorothy Bennet said UV light enabled people to produce essential vitamin D but also increased the risk of skin cancer – so controlling exposure was key.

“It is important that we can depend on suncreams to provide the protection they claim,” she said.

“We may be able to realise if protection is lower by getting sunburn – but then it’s too late.

“It is good that so many suncreams passed Which’s testing but disturbing that several creams failed to protect as advertised.”

Prof Bennet said there could be a number of reasons for the differing results stated by Which? and some of the companies involved, including how thickly the sunscreen was applied, on which part of the body and the exact waveband of UVB or UVA light used.

According to NHS advice:

• Do not rely on sunscreen alone – wear suitable clothing and spend time in the shade when the sun is at its hottest

• When buying sunscreen, the label should show, at least, an SPF of 30, to protect against UVB, and four-star UVA protection – the letters “UVA” in a circle indicates it meets the EU standard

• Make sure sunscreen is not past its expiry date

• Do not spend any longer in the sun than you would without sunscreen