The sun's ultraviolet A (long-wave) and ultraviolet B (shortwave) rays. Most of us are exposed to large amounts of UVA throughout our lifetime. UVA, which penetrates the skin more deeply than UVB. UVA damages skin cells called keratinocytes in the basal layer of the epidermis, where most skin cancers occur. UVB, the chief cause of skin reddening and sunburn, tends to damage the skin's more superficial epidermal layers. It plays a key role in the development of skin cancer and a contributory role in tanning and photoaging. The most significant amount of UVB hits the Norway between 11.00 and 15.00 from May to September. SUN SP50+++ contains: Hyaluronic Acid: Natural Moist. Factor, able to penetrate the skin’s upper layers to improve and benefit the skin when applied. Penetrates into the dermis, thus boosting the elasticity and hydration of the skin.