The problem might lie in your digestion. If you are not digesting food well, causing nutrient and protein deficiency this can cause hair loss. This can be caused by a bacteria infection which stops stomach acid production causing poor protein absorption and causes considerable stress on the body and immune system. These bacteria replace the digestive mucosa with a biofilm which allows large food molecules to enter the blood stream which cause an immune reaction ie autoimmune which has a very negative effect on the body and immune system and is a physical stress on the body. These Stresses cause the nervous system function near the skin to reduce, reducing healing/repair near the skin and lowering nutrient availability to the skin/hair. These conditions all put together can cause hair loss.
I would not waste money on some "magic" herb to regrow your hair. You need to remove the cause and concentrate on your digestion. Investigate whether it is functioning correctly and that you are producing sufficient stomach acid.
Do a stomach acid test: http://livingfoods.co.uk/the-acid-test-by-philip-weeks/
After that try drinking some lemon juice and see if you burp, this MIGHT indicate the effect of urease which is used by bacteria to neutralize stomach acid using the urea in saliva to produce ammonia (a base) to neutralize stomach acid. If this is the case your protein digestion is likely to be very poor and your nutrient absorption, especially minerals is likely to be poor.