Shea butter, also known as karite butter, is a cream-colored fatty substance made from the nuts of karite nut trees (also called Mangifolia trees) that grow naturally in the savannah regions of West and Central Africa. Shea Butter has been used by the African people for generations to soften, moisturize and heal skin damaged by the heat and sun. It can also be used to help heal burns, sores, scars, dermatitis, psoriasis, dandruff, and stretch marks. It may also help diminish wrinkles by moisturizing the skin, promoting cell renewal, and increasing circulation. Shea butter also contains cinnamic acid, a substance that helps protect the skin from harmful UV rays.

Shea butter is a particularly effective moisturizer because contains so many fatty acids, which are needed to retain skin moisture and elasticity. That is also what makes it an excellent additive to soap, shampoos, anti-aging creams, cosmetics, lotions, and massage oils—its soft, butter-like texture melts readily into the skin.

It also protects the skin from both environmental and free-radical damage. Rich in vitamins A and E, it has demonstrated antimicrobial and anti-inflammatory properties.

Environmentally and Socially Speaking
Karite trees, or shea trees, are not cultivated. They grow only in the wild, can take up to 50 years to mature, and live up to 300 years. In most parts of West Africa, destruction of the karate nut tree is prohibited because it provides a valuable source of food, medicine, and income for the population. In fact, shea butter is sometimes referred to as “women’s gold” in Africa, because so many women are employed its production.

References
http://www.vitaminstuff.com/supplements-shea-butter.html
http://en.wikipedia.org/wiki/Shea_butter