Using endogenous antioxidant above may have already given away the answer
This is completely normal and is a sign that the active, reduced glutathione is present, as sulfur is a core component of the molecule
[DOI] [PubMed] [Google Scholar] 70.Zemba Cilic A., Zemba M., Cilic M., Balenovic I., Strbe S., Ilic S., Vukojevic J., Zoricic Z., Filipcic I., Kokot A., et al
Journal of Biomaterials Science, Polymer Edition
N-Acetylcysteine (NAC) NAC is a precursor to glutathione and has been shown to effectively increase its levels in the body
(2) The male steady state is slightly different than in [11] , so we adjust the steady states of S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and Bet, which occur in the velocity equation for CBS and the velocity equation for betaine-homocysteine methyltransferase (BHMT)