There are many products in the market which allegedly cure hair loss. Scientifically, the only product which has been proved to be moderately effective is minoxidil.
Originally, minoxidil was developed as a treatment for high blood pressure. It was observed that there was regrowth of hair as a side effect. UpJohn Corporation developed a topical solution 2% solution of minoxidil, for hair loss. The brand name of this product is Rogaine in United States, and Regaine in Europe.
The precise mechanism by which minoxidil works is unknown. The most common theory is its vasodilating effect. This means it relaxes the blood vessels. It may be the case that the hair follicles are stimulated in this way, causing growth of new hair. Another theory is that calcium is reduced in the hair cell follicles. For male pattern baldness, minoxidil promotes hair regrowth in the frontal areas of the scalp as well as in the central area.
Minoxidil is applied topically to the scalp twice a day. The treatment is supposed to continue for the rest of your life, otherwise hair will be lost again within a few months. This is official advice. Personally, I have had a different experience. I used Regaine for about a year, and then stopped using it, because I couldn't afford it. To my surprise, I didn't lose hair. In fact, I haven't needed to use it again, it's been ten years now. I don't know why this is, but in theory the hair regrowth should have been lost. I'm not at all recommending that everyone else should do what I did, just that this was my personal experience.
According to scientific research, the overall success rate varies. In people in their twenties, in the early stages of hair loss, the success rate is very high. However, someone in their fifties, in late stages of hair loss, may have a low chance of success. Age and stage of hair loss are the key factors. For some people, the positive effects may diminish over time, due to a tolerance being developed.
Recently a 5% solution has become available for men, which is more effective. The higher concentration does not seem to make a difference to women.
Minoxidil also thickens existing hair.
SIDE EFFECTS
If used within the recommendations, most people will not experience side effects. Obviously, each person must decide if the overall benefits outweigh any side effects. Of those side effects which can occur, an itchy scalp is the most common. It is also possible to suffer skin blemishes, headaches, lightheadedness, blurred vision, fast or irregular heart rate, numbness and pain in the chest.