The SOLUTION can be used on all hair, its base being similar to that in most minoxidil preparations. However, it is particularly recommended for those with naturally straight hair who do not need or tolerate the addition of oils to their hair. The active ingredients, Serenoa Repens, Brahma Buti, and Eun-haeng are the same as in the other formulas but at a higher concentration to compensate for the elimination of healing oils. This was the first formula created by The Drug Doctor and has been shown to help most users grow thicker, stronger, and more styleable hair within months of use. It is therefore recommended that a picture be taken of the scalp at the start of treatment and then in the coming months so that changes are easily recognizable. The formula is lightly scented with pure extracts of Almond and Honey. Results are guaranteed or your money back. You are also able call Dr. Gray, The Drug Doctor, EST between 9am and 6pm for any related hair care questions at 757-949-3297.