The active ingredient in Rogaine, minoxidil, works by increasing hair follicles and strengthening existing hair to grow thicker. The exact process that causes this reaction is still unknown and has not been studied fully as of November 2014; however, Rogaine is still considered safe since long-term side effects are usually limited to itchy scalps and dandruff.
Rogaine offers two solutions: 2 percent and 5 percent. WebMD reports that men who try the 5 percent solution report better results but have also displayed more of the side effects. Hair growth is not always satisfactory; even with Rogaine, some men report growing only thin and wispy hair or hair more similar to peach fuzz. Rogaine is most effective on men younger than 30 who have begun suffering from hair loss within the last five years.
Rogaine is most commonly used to treat inherited hair loss, but it can be used to treat other types. The company website recommends that Rogaine be applied twice daily and that results can take up to four months to show. Users should not stop using Rogaine once hair growth resumes; discontinuing use of the product often causes hair loss to return, and the scalp often reverts completely within six to 12 months. Rogaine is also safe for women to use.