It was a about a kid the takes some kind of potion to get rid of or get something can't remember which. Then he goes bald. The kid gets another potion to grow hair and his hair grows rupunzel length he his then kidsnapped an the evil guy uses his hair to make paint brushes.

The Peanut Butter Solution
The Peanut Butter Solution (1985) - IMDb (http://www.imdb.com/title/tt0089789/)

I guess your right. It's The Peanut Butter Solution 1985 Movie.