EU-funded tests comparing two ways of checking sunscreen protection found that a laboratory method can provide reliable results without exposing human volunteers to UV radiation.
A total of 74 products — including sunscreens and day creams — were tested for sun protection factor (SPF) and UVA protection in laboratory conditions, known as in vitro testing, the European Commission announced on Tuesday.
The products were selected from shops and online by market surveillance authorities from 11 EU countries.
Results showed a high correlation between laboratory testing and conventional testing on people, supporting the use of the laboratory method to verify SPF claims.
The in vitro method used was EN ISO 23675:2024, a testing standard published in December 2024.
Unlike conventional in vivo testing — which measures skin redness after UV exposure — the laboratory approach avoids inducing sunburn in volunteers.
Why laboratory testing can differ from tests on volunteers
Some sunscreens contain anti-inflammatory or soothing ingredients that can reduce or delay erythema, or redness, which is used to calculate SPF in tests on volunteers, the Commission said.
That can lead to an artificially higher SPF result in human testing.
In the laboratory method, sunscreen is applied to two types of acrylic plates — one moulded and one sandblasted to mimic skin texture — under tightly controlled conditions including application amount, temperature and drying time.
A spectrophotometer then measures how much UV passes through the sunscreen layer, and an algorithm is used to calculate SPF based on results from both plate types.
Manufacturers were advised to prioritise test methods that do not cause harm to human volunteers when determining SPF and UVA protection, the Commission said.
It noted that the current laboratory method cannot yet be used for sunscreen sticks and powders, and said standards bodies should work on extending non-invasive testing to include those products and water-resistance claims.
The work was carried out under the 2025 Joint Actions on Compliance of Products (JACOP) campaign in the EU and EFTA countries, which involves joint testing by national market surveillance authorities across multiple product types.
“Market surveillance campaigns help to protect businesses from unfair competition and ensure that products sold on the single market are safe for consumers,” said Vanessa Capurso, a policy officer from the Directorate-General for Internal Market, Industry, Entrepreneurship and SMEs
