glutathione functions in body - an overview Glutathione for Dogs: Benefits, Dosing
Description
J Physiol Biochem 2011

Wang Z, Zhang Y, Ju E, Liu Z, Cao F, Chen Z, et al
The prescribing information states "colorless to slightly yellow," so a very subtle yellow is perfectly normal

Very affordable a Seems to be working well
Improvement in dark spots and pigmentation is possible, but varies from person to person

However, there has been individual limitation on its use, and some even are fatal
