Proof of Antioxidant Efficacy / ICL-S/H
Induced chemiluminescence of skin and hair (ICL-S/H) is one of the few methods available to demonstrate in vivo an oxidative protection potential. The chemiluminescence detection system was developed as part of a research project in collaboration with m.u.t. GmbH (Wedel, Germany) in the late 1990s. Conceived as an in vivo single photon counting system, the result was a technology that quantifies oxidative stress in the skin and hair by means of a Peltier-cooled photomultiplier. Through spatial separation of the detection unit and control unit with sun simulator a non-invasive technique could be developed that detects photons emitted by the skin or hair less than 100 ms after stress termination and so makes it possible to obtain directly a cosmetic proof of efficacy of the oxidative protection potential.
Modern cosmetics with efficacy claims like “anti-ageing” are complex mixtures of UV filters and antioxidants. Proof of efficacy for such claims must be obtained with established scientific methods. Sunlight (UV radiation) is the main cause of premature skin ageing (photoageing), primarily due to generation of free radicals and the oxidative stress associated with them. The biggest challenge in claim support is non-invasive yet sensitive measurement of oxidative stress in test persons. This is the only in vivo approach that takes into account all physiological processes in living skin and provides efficacy data with the greatest possible relevance for the in-use situation. UV filters reduce radical formation and antioxidants produce a faster and/or more effective radical neutralization and detoxification. By measuring the chemiluminescence (ultraweak photon emission) as the by-product of radical reactions in biological tissue like skin, the ICL-S method (induced chemiluminescence of human skin) allows measurement of oxidative stress in real time in groups of test persons. Proof of efficacy of antioxidants and UV filters can therefore be provided for raw materials during product development and for finished products after topical application (in-use situation), both on human skin and on hair.