It worked wonders for me, (although i never tore my acl or mcl)
I had some pretty bad osgood schlatters (sp?) and then later patella tendonitis in my left knee
without it i honestly dont think i could have played football or basketball in high school (coulda got by in baseball though)
putting any type of pressure on my left leg gave a sharp pain sometimes, and my knee would ach the entire next day if i played a game of basketball
taking them twice daily helped tremendously, and i even was able to start squats & leg extensions
once again i have no idea how much it would help for a MCL, but it wouldn't hurt to at least give it a shot
I took Glucosamine, MSM, and chondroitin sulfate. these supps were alot harder to find when i first started taking it like 5 years ago, but now theres a comboof all 3, and i'd recommend that one
i don't remember the exact mechanism (as i researched this years ago), but to my understanding it was more effective when all 3 were taken at once