Ceramides are essential lipids (fats) naturally found in skin's outermost layer. Ceramides are a part of skin's natural moisture factor (NMF) and help lock in moisture, prevent water loss and protect skin from environmental stressors, irritants and pathogens. Ceramides are used in skincare products like creams and lotions, to replenish the skin's natural barrier and improve the skin's ability to protect itself from environmental stressors.