glutathione is found inside the human body, as one ages, and is exposed to pollution, sunlight, and other environmental factors (oxidants). glutathione leveles reduces, thus resulting to premature aging and ofcourse leaving your skin and body to potential damage. L-glutathione on the other hand is the reduced form of glutathione, it is the medication use to increase the levels of glutathione in the body, studies have also shown that the reduced form of L-glutathione is also responsible for the whitening effect on the skin. If you wish to know more, please visit www.theswisscare.com you can also learn about their product SWISS L-glutathione bar or SW+SS L-glutathione bar. reaaly hope this helps. :)