Male Pattern Baldness
Male pattern baldness, or androgenic alopecia, is the most common cause of hair loss. According to "Current Diagnosis & Treatment in Otolaryngology," "Thirty percent of 30-year-old men and 50 percent of 50-year-old men suffer from male pattern baldness." When someone inherits a genetic susceptibility to androgenic alopecia, they may begin to lose hair sometime between the ages of 12 and 40. It typically manifests as a receding hairline along the sides of the scalp followed by a progressive thinning of hair at the vertex, or top, of the head. The hair loss advances at different speeds for different people.
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To understand how male pattern baldness works you need to understand how testosterone is converted into dihydrotestosterone or DHT. In various cells throughout the body, an enzyme called 5-alpha reductase converts testosterone to DHT. DHT can be thought of generally as a stronger form of testosterone, but it also has specific jobs of its own. One of these is to manage hair growth on the chin, chest and underarms. To perform this function, it has the ability to bind to special receptors on hair follicles. Individuals with a genetic predisposition to male pattern baldness have similar receptors on the hair follicles in their scalp that, instead of promoting hair growth when bound by DHT, actually thin hair and cause hair loss. There is no cure for male pattern baldness, but its progression can be slowed in some men using a drug called minoxidil.
Minoxidil was actually first used as a drug to treat extremely high blood pressure. Taken orally in pill form, it dilates (or widens) small arteries in the body causing the resistance to blood flow to decrease. Unfortunately for some, particularly for female patients taking the drug, it has a high tendency to cause hypertrichosis, or excessive hair growth. Recognizing that this effect would be welcomed by other patients, drug manufacturers developed a topical formulation so that the hair growth could be enjoyed while avoiding the arterial dilation of the oral drug.
Minoxidil appears to work by widening the hair follicle, causing a thicker strand of hair, and by prolonging the anagen stage of hair growth which results in longer and a higher number of hair strands. The exact physiological basis for these effects remains unknown, but it has been shown to be safe and effective when used properly. According to "Fitzpatrick's Dermatology in General Medicine," studies have shown that "up to 60 percent of men show improvement in vertex balding...with a mean increase in hair density of 10 percent to 12 percent."
There are two strengths of minoxidil: 2 percent and 5 percent. The 5 percent has been shown to be more effective without a significant increase in irritation or other side effects. Both strengths are applied to the dry scalp twice a day. It is important to know that the treatment must be continued indefinitely to maintain results, as any hair gains will be lost within four to six months if the patient discontinues the drug. Be sure to wash your hands thoroughly after applying minoxidil so it is not spread to other parts of your body.