Hairgaine 5% Topical Solution is a medicine used treat common hereditary hair loss in men aged 18-65 years, by preventing further hair loss and helping hair re-growth. It contains Minoxidil which is thought to work by aiding the blood flow to the hair follicles on your scalp. Hairgaine works best in Men with hair loss or thinning at the top of the scalp. Those who are younger have been losing hair for a short period of time or have a small area of baldness are likely to experience the best results. You are unlikely to benefit from Hairgaine if you have been bald for many years or have a large area of hair loss.