Also known as Met Tathione, metathione is a type of oral supplement marketed as a skin lightener. Also simply called MET, the Met Tathione brand also offers a soap under the same name for the same purpose of skin lightening.
The Met Tathione brand appeared on the Philippines market in 2002 and was the first product in the country with supposed skin lightening effects. The brand is also responsible for starting the glutathione skin whitening trend in the Philippines. Although glutathione supplements are available in the West primarily as an antioxidant, the product is more popular in Asia as a skin lightening agent, particularly in the Philippines where having fair skin is generally more aesthetically pleasing.
Glutathione is a tripeptide thiol made up of the amino acids l-cysteine, glutamic acid and glycine. It is widely available as one of the most potent antioxidants. However, its effectiveness as an oral supplement is in dispute because peptides generally have poor bioavailability. A 2011 study published in the Journal of Alternative and Complementary Medicine explored the effects of orally administered gutathione on human volunteers. The study concluded that oral glutathione supplements do not have a significant effect on the biomarkers of oxidative stress in healthy adults.