Health Freaks (2009)

Alex and Joe are two comic book loving janitors who work for Health and Fitness Plus. Sammy Rocanter is a crooked salesman who brings in a new energy drink to sell to the health club members. However, this energy drink still has some kinks in it. Health club members are turning into mutants and killing each other. You'll enjoy "Health Freaks," the only horror/comedy movie with mutants, toxic energy drinks, and Jehovah's Witnesses.