Even if you don't have a genetic mutation that compromises your body's ability to manufacture adequate levels of glutathione, life in the modern world means that most of us are probably suffering from glutathione deficiency
Hepatotoxicity: A review published on PubMed Central (PMC) highlighted concerns about liver stress with prolonged, high-dose glutathione use
Biophysical Journal 110 , 423a, doi:10.1016/j.bpj.2015.11.2287 (2016)
Direct research vendors like Koi, Limitless Life Nootropics, and Swiss Chems are easy for an individual to order from, and the good ones publish batch COAs or independent test results
Keep away from the freezer compartment and door shelves where temperatures fluctuate
That is why in your genetic raw data, you will see G for the typical and A for the variant, but many research studies will still include C for the typical and T for the variant