Find us on...
In December 2024, the International Organisation for Standardisation (ISO) published two new methods for measuring the Sun Protection Factor (SPF) of cosmetic products. One method is in vitro, meaning that it does not require human volunteers, and one is a hybrid method, which provides a non-invasive optical assessment of the protection provided by sunscreen on human skin, without requiring a physiological skin response.
As the methods are now published, they are available to be used by industry as alternatives to the current ISO 24444 method to measure the SPF of cosmetic products.
These robust methods are the result of many years of work by dedicated suncare experts. The in vitro method ISO 23675, known as the Double Plate Method (DPM), was led by Cosmetics Europe and scientists from its member companies. The hybrid method ISO 23698 was led by experts from the suncare products and ingredients industry. During their development, both methods have undergone extensive work to ensure their correlation with in vivo assessments using ISO 24444.
It is important to highlight that companies do not rely just on one measurement for the SPF value: a weight of evidence is produced. Companies should select the most suitable test method for their formulations, and continue to build up and document a dossier of data that supports the final SPF and UVA protection labelled on pack.
Please see below for the links to the ISO publications (available for purchase) and more details on the methods.
ISO 23675:2024 - In vitro determination of sun protection factor (SPF)
- The in vitro determination of SPF or Double Plate Method (DPM) has been developed by Cosmetics Europe expert members. The DPM does not require human volunteers to measure SPF, which makes it a fully in vitro SPF method. It provides reliable, repeatable and reproducible results.
- The DPM is applicable to sunscreen products in form of an emulsion or alcoholic one-phase formulation, excluding in form of a loose or compressed powder or stick.
- The method is not applicable for the determination of water-resistance properties of a sun protection product.
ISO 23698:2024 - Measurement of the sunscreen efficacy by diffuse reflectance spectroscopy
- The Hybrid Diffuse Reflectance Spectroscopy (HDRS) method is a process to characterise the SPF, UVA protection factor and critical wavelength protection of sunscreen products without requiring biological responses.
- The method is applicable for emulsions and single-phase products, but it has not been evaluated for use with powder forms sunscreen products.
- HDRS gives specifications to enable determination of the absolute spectral absorbance characteristics of a sunscreen product on skin to estimate sunburn and UVA protection.
For any questions, please contact Francesca Rapolla.