UFC fighter Lyman Good claims his multi-vitamin was tainted with an illegal steroid, causing him to fail a drug test -- and now he's suing the vitamin companies allegedly responsible for his dirty test.
TMZ Sports has obtained the lawsuit filed in New York ... in which Good claims he went to a Vitamin Shoppe store before his fight at UFC 205 and purchased Anavite, a multi-vitamin.
Good claims he failed his USADA drug test -- which came up positive for 1-andro ... an illegal anabolic steroid.
Good says he turned over all of his supplements to the United States Anti-Doping Agency (USADA) for further testing and it showed Anavite secretly contained 1-andro .