Glutathione through glans penis

Would rubbing liquid from a softgel be more effective? You can easily get 600mg glutathione softgels

I think the OP may have been conflating the results of PE exercises, which can be delayed by overzealous use causing temporary shrinkage. This phenomenon probably is the cause of sporadic measurements. It is hard to tell what is producing results when testing multiple things simultaneously (some methods may only work in conjunction with something else).

Glutathione can be increased by DMSO. I don’t remember anyone getting any size increases from DMSO, though some wrote they saw improvements in erection quality.

DMSO is toxic in some concentrations to various cells, not just neurons, sometimes under 1% by weight. Blood movement and the rate of absorption through the skin might mitigate this risk. DMSO also carries some other risk, which is largely unknown though some serious issues have been documented, when combined with other substances.

Since glutathione is an endogenous substance, we at least know concentrations normally occurring do not work.