It has not been proven that any product applied externally to the hair or scalp can promote, advice physician stimulate, cure or accelerate natural hair growth.  Most people who complain of little or no hair growth are blaming it on the wrong reason.  They think the problem is lack of natural growth form the scalp, when in reality; the problem is the hair is breaking off from the ends for a variety of reasons.  If hair growth stops, then baldness begins, and yet you have people complaining their hair has not grown at all over a period of years.  If the person has hair, then it is growing.  Once hair stops growing, it is eliminated by way of attrition.  In other words, as every hair shaft dies out due to the normal life span of the hair shaft (5 to 7 years), then it will not be replaced by another.  Therefore, permanent baldness becomes apparent.