Crocus sativusflower extract restores circadian rhythm

Active ingredients suppliers aim to understand the mechanisms of skin’s self-defence, and to provide the best products to fight those external aggressions. 

Sun’s effects on skin Humans have always been submitted to the luminous environment which follows a day and night alternation. This variation of light is perceived by an internal clock, localised in the brain, which synchronises biological mechanisms with our environment. For example, skin cell proliferation is higher during the night, when the probability of DNA alterations by solar UV is minimal.1 

Indeed, it has been extensively described that intense sun exposure negatively impacts the skin. Sunburn or ‘erythema’ is one of the first visible effects of UV exposure. It is an inflammatory reaction which induces a reddening of the skin. This phenomenon is a kind of alarm that indicates us to protect our skin by stopping the exposure. However, many invisible processes happen deeper in the different skin layers. The surface of the cutaneous tissue is modified (pleated, fragile, dry, hyper- or hypo- pigmented...) as well as its structure (loss of elasticity, thickness, wrinkles...). The epidermis is thinned, and the epidermal junction flattens out. In the dermis, very important changes in the structure and organisation of the extra cellular matrix (ECM) occur: accumulation of abnormal elastic fibres in the reticular dermis; disorganisation of the collagen network; decreased collagen content due to the stimulation of matrix metalloproteinases (MMPs) and their inhibitor TIMP-1. At the molecular level, DNA damages appear, proteins are altered, notably because of the presence of free radicals that generates reactive chemical species. In the long term, these damaging effects lead to photoageing and cutaneous cancers.1 This is the reason why we must protect our skin by avoiding too much exposure and by using cosmetics containing active ingredients which counteract those harmful UV effects.