There are many substances that are very useful during the first 24 hours because they break or stop the cascade of brain injury chemistry. Glutathione looks like one of them. I have not seen any research that suggests use days or weeks later.

Some suggest taking many substances as a normal regimen, maybe in hopes that if you suffer a head impact with the substance in your system, your injury will be less. The challenge to this idea is the body likes to keep a balance of how much of these substances is naturally available.

I've wondered is they will eventually develop a post head trauma cocktail for athletes and others who have suffered head impacts that can be administered/consumed right away.