EU study finds lab sunscreen SPF tests can replace sunburn testing on volunteers

The European Commission says laboratory sunscreen tests could reduce the need to expose human volunteers to ultraviolet radiation that causes sunburn.

A Commission-funded campaign compared laboratory testing with conventional tests performed on people. It examined the sun protection factor and UVA protection factor of 74 products, including sunscreens and day creams.

Market surveillance authorities from 11 EU countries selected the products from shops and online retailers.

The Commission’s Directorate-General for Internal Market, Industry, Entrepreneurship and SMEs said the results showed a high correlation between laboratory testing and conventional testing on human volunteers.

It said the findings support the reliability of laboratory methods for checking whether sunscreen products meet their advertised SPF claims.

The laboratory method, EN ISO 23675:2024, was published in December 2024. The Commission said it is faster and cheaper than testing on people and removes the need to expose volunteers to UV radiation.

During the test, sunscreen is applied to two types of acrylic plates designed to imitate the texture of human skin. The amount of sunscreen, application method, temperature and drying time are controlled.

A spectrophotometer then measures how much UV radiation passes through the sunscreen film. An algorithm calculates the SPF using results from both types of plate.

The Commission said laboratory testing is not affected by the availability or skin condition of volunteers.

It may also produce more reliable results when products contain anti-inflammatory or soothing ingredients. Such ingredients can reduce or delay visible skin redness during tests on people, potentially affecting the measured SPF result.

Manufacturers were advised to prioritise SPF and UVA testing methods that do not harm volunteers.

However, the Commission said the current laboratory method cannot be used to test sunscreen sticks or powders. It called for non-invasive testing to be expanded to cover those products and sunscreen water-resistance claims.