UVA (ageing, DNA and cell changing) penetrates below the skin's surface and requires a high level UVA filter in the sun protection you choose.UVB (burning) causes the ‘sunburn' we may see ourselves after overexposure. UVB is measured by SPF (Sun Protection Factor). The SPF rating system was developed back in 1962 by Franz Greiter to measure the capacity of a sunscreen to block UVB radiation. The current SPF rating system applies to UVB rays only, since those are the rays that cause sunburn.    Infrared-A : Infrared-A rays penetrate the epidermis and dermis and can lead to the formation of free radicals. Antioxidants are the key to infrared-A and DNA defence.HEVL (blue light or High Energy Visible Light), is emitted from electronic devices such as tablets, computer and fluorescent lighting.  HEVL (blue light) penetrates more deeply into the Epidermis and generates free radicals. These cause skin cells to product enzymes that break down collagen and elastin. This process is known as oxidative stress and it's what causes skin to photo age which can lead to hyperpigmentation.