It works by inhibiting the production of melanin, the pigment responsible for the color of our skin
Biomaterials 144 , 119129 (2017)
It needs to be consumed in the form of cystine, so it survives digestion, and gets into the cells intact, where it can be stored until needed to make glutathione when it is needed by the cells
This is a real GH-physiology consideration
This decline from 200 ng/mL to 80 ng/mL correlates directly with decreased regenerative capacity and visible signs of aging
(Reference Gayatri, Kumar and Kumar28) , participants were not randomly assigned to the intervention and control groups, and seven studies described an allocation concealment method (Reference Hassan, Alalfy and Hassan18,Reference Badawy, El Nashar and El Totongy20Reference Hashim, Anwar and El-Fatah22,Reference Elgindy, El-Huseiny and Mostafa23,Reference Ghomian, Khadem and Moeindarbari5,Reference Maged, Elsawah and Abdelhafez8)