It is a bit pricey, about $1 (CDN) per day on a 500mg daily dose. References I found for head trauma/concussion recovery were almopst all based on small groups and only on short term studies primarily. Some were inconclusive others were so optimistic it made it sound miraculous.

I may give it a try, it may not be as effective for those who move further in time away from injury. As a note, looking at trying the one by AOR research.