A:MacTheKnife is absolutely right...
Hair growth/loss is related to the production of DHT in hair. It's important to maintain a healthy diet and lifestyle. Try to use good products as well (be mindful of alcohol content in your goop!) Use good products like MiN New York's DHT Salon Defense Cleansing System (min.com). For more info, read this:
http://www.askmen.com/fashion/fashiontip_150/181_fashion_advice.html