Glutathione can be found in virtually every cell of the human body. The highest concentration of glutathione is in the liver, making it critical in the body's detoxification process. In addition to its many recognized biological functions, glutathione has also been associated with skin lightening ability. Glutathione can be combined with many other agents like vitamin C to increase its absorption, N-acetyl cysteine to boost its level, and other antioxidants like vitamin E.