ISO 24443:2012, Determination of sunscreen UVA photoprotection in vitro, gives specifications for an in vitro procedure to characterize the UVA protection of sunscreen products in accordance with a methodology defined in the standard.

It is widely accepted that overexposure to the rays of the sun can have harmful effects on the skin. In 2006, the World Health Organization (WHO) published the report, "Solar ultraviolet radiation: Global burden of disease from solar ultraviolet radiation", that estimates that up to 60 000 deaths a year worldwide are caused by too much exposure to ultraviolet radiation.

When first created, sunscreens were only designed to filter out UVB, as the dangers represented by UVA were then unknown. Today, sun protection products must span the entire UV spectrum.

Sun damage to skin is caused by UVA and UVB rays. UVB and UVA are different in their intensity, wavelength and their ability to penetrate the layers of the skin.UVA rays are not as powerful as those of UVB, but they are more abundant and penetrate the skin to a greater depth. This then leads to a slackening of tissue, a loss of skin firmness and the appearance of wrinkles. These rays penetrate so deeply that they can lead to genetic changes, affecting DNA, and resulting in the onset of skin cancer. UVA is also responsible for triggering photosensitizations in reaction to the consumption of certain pharmaceuticals.

ISO 24443 gives specifications to enable the determination of the spectral absorbance characteristics of UVA protection in a reproducible manner to help manufacturers and testing laboratories.

Pr. Philippe Masson, Chair of the ISO group of experts that developed the standards, comments: “The trade in cosmetics between different countries is increasing. ISO 24443:2012 will be an important tool in improving the quality and safety of sunscreen products and facilitating their global trade. It will also help manufacturers to better respond to local requirements for sunscreen products and give better information to consumers.”

ISO 24443:2012 was developed by ISO technical committee ISO/TC 217, Cosmetics, working group WG 7, Sun protection test methods. It is available from ISO national member institutes (see the complete list with contact details). It may also be obtained directly from the ISO Central Secretariat, price 122 Swiss francs through the ISO Store or by contacting the Marketing, Communication & Information department.