In a previous tweet, we shared with you that UV light is the most potent and cumulative of all exogenous skin aging-causing factors, causing sun redness, tanning, photoaging, various light-based skin diseases, and skin cancer. However, visible light and infrared radiation can also cause some damage to the skin, and the reaction is caused by oxidative damage due to molecular vibrations and increased temperature. Infrared damage to the skin Infrared radiation (>760nm) causes thermal radiation that penetrates the skin more than ultraviolet light. 25% to 65% of its radiation reaches the epidermis and dermis, and 8% to 17% reaches the subcutaneous tissue. Infrared radiation, through its thermal radiation effect, increases the skin temperature, capillary dilation, congestion, and increases the evaporation of epidermal water, thus directly causing adverse effects on the skin. The main manifestations are red papules, premature aging of the skin and pigmentation disorders. Infrared rays can also enhance the damaging effects of UV rays on the skin and accelerate the skin aging process. At the same amount of UV intensity, the SPF (Sun Protection Factor) measured in natural outdoor sunlight is significantly lower than that measured in the laboratory under artificial light, which is caused by the dual action of UV and infrared rays on the skin in natural sunlight. Visible light damage to the skin Visible light (400-700nm) carries less energy, and the damage to the skin is mainly the production of free radicals and pigmentation. It penetrates biological tissues and radiates on the skin to produce ROS, accompanied by photon-induced activation of endogenous photosensitizers. The skin chromophore of visible light contains heme, melanin, bilirubin, riboflavin and porphyrins, which also induce the production of inflammatory factors and increase the amount of degrading enzymes in the skin epidermis. Visible light, in dark skin, also causes hyperpigmentation and is suspected to aggravate melasma. Experiments have shown that the blue light band in visible light causes increased skin discoloration, and discoloration induced by blue light is more stubborn than UVB-induced discoloration. Summer skin care products preservation methods 1, avoid exposure to the sun and high temperature to prevent the product loss of activity, encourage bacteria. 2, moisturizer and mask and other skin care products can be put into the refrigerator, but also pay attention to the isolation of ingredients to avoid the smell of string and bacterial contamination; powder, lipstick and other cosmetics do not need to be put into the refrigerator, cool place to store. 3, in addition, no matter what season, should try to avoid the bathroom moisture to skin care products brought about by the humidity impact. You can choose to separate your skin care products from the shower, or avoid keeping them in the bathroom.