Overview of Skin and Sun Exposure Skin is the largest organ of the human body and acts as a protective barrier against environmental factors such as microorganisms, chemicals, and radiation. It plays an important role in maintaining body temperature, preventing water loss, and protecting underlying tissues. Therefore, proper skin protection is essential to maintain its health and function. Exposure to sunlight is a major environmental factor affecting the skin. While moderate sunlight is beneficial for vitamin D synthesis, excessive exposure can be harmful. Sunlight contains ultraviolet (UV) radiation, which can cause sunburn, skin irritation, premature aging (photoaging), pigmentation, and in severe cases, skin cancer. Continuous exposure to UV rays also leads to the generation of free radicals, which damage skin cells and accelerate skin aging. Hence, protecting the skin from harmful effects of sunlight is necessary for maintaining healthy skin.