Which vitamin is primarily produced by the skin?

The skin primarily produces Vitamin D when exposed to ultraviolet (UV) rays from sunlight. When UV rays penetrate the skin, they convert a cholesterol derivative in the skin into Vitamin D3, which is then further processed by the liver and kidneys to form the active hormone, calcitriol. This active form of Vitamin D plays a critical role in calcium absorption and bone health, among other functions.

The production of Vitamin D through skin exposure to sunlight is significant for maintaining optimal levels of this nutrient in the body, particularly in situations where dietary intake may be insufficient or where individuals may have limited sun exposure. This unique ability of the skin to synthesize Vitamin D sets it apart from other vitamins, which are typically obtained exclusively through diet or supplementation.