Does doo gro work

Doo gro really works. I'v been using it since May of 2010. Now it's October and my hair has grown about 5-7 inches. I heard that Doo gro don't work on African American people, but it works for me, and I'm mostly African American. I know it's very greasy, but it smells good. All you have to do is fully grease your head from scalp to ends once a week.