10.1001/archpedi.1995.02170190042007 Arch
The idea is not baseless: dose-response curves for GH secretagogues do plateau, and the Bowers work explored GHRP across a 0.1 to 1.0 mcg/kg range, so a saturation region in that neighborhood is a reasonable-sounding extrapolation
However, a one-year randomized, double-blind, placebo-controlled trial in 253 elderly (65 years) adults with elevated homocysteine levels found that B vitamin supplementation (1,000 g/day of folate, 10 mg/day of vitamin B 6 , and 500 g/day of vitamin B 12 ) did not improve measures of cognitive function, including memory, despite lowering homocysteine levels (116)
There are different ways to take it, including glutathione sublingual, oral supplements, IV therapy, and topical creams