A more likely reason for deficiency would be low absorption in the gut, probably because of pernicious anemia or another condition
PMCVogue Musculoskeletal Repair: Rodent Achilles-tendon models regained tensile strength faster with local GHK-Cu injections
PMID: 286 GongYMaXHuangJZhangPHaiYSongYet al
However, glutathione production declines with age , and factors like poor diet, high stress, alcohol consumption, and exposure to toxins further deplete levels
10.1038/s41582-021-00578-6 32 BoiangiuR
The extraction was done in a buffer [1.0 mm ethylenediaminetetraacetic acid (EDTA), 100 mM TrisHCl (pH 7.3), 100 mM -mercaptoethanol, 1.0 mM phenyl methyl sulfonyl fluoride, 0.1 mM protease inhibitor cocktail, 2% glycerol, 25 mM MgCl 2 , 10 mM dipotassium hydrogen phosphate (K 2 HPO 4 )] and centrifuged at 12,000 g for 15 min, 4 C