Hair has three phases of growth: 1) anagen, 2) catagen and 3) telogen.
The anagen phase is the hair growth period. It generally lasts for about eight years. At any given time, 85% of hair follicles are in the anagen stage. People with long anagen phase can grow long hair. Hair grows, on average, one half inch per month. The exact length of anagen time is determined genetically. In males who are prone to hair loss, the follicles are more sensitive to DHT (dihydrotestosterone) induced hair loss. When blood concentrations of DHT reach a certain level, hair shafts begin to miniaturize and subsequently fall out. DHT puts hair follicles into the catagen stage. This is the transitional phase of hair follicles. Normally it lasts for about two weeks. The hair shaft is detached from the hair follicle papilla and is pushed upward. The hair shaft does not necessarily fall out.
Catagen phase is followed by the telogen phase. This is the resting or dormant phase which lasts 1-4 months. For those follicles that come out of this dormant phase, they go back into the anagen phase where new hair growth occurs. The old hair shaft is pushed out by the newly growing hair. An average of 75 hairs are lost daily by most people. In hair loss treatments, stimulation of many follicles at once causes them to go from telogen to anagen phase. Shedding can occur during this 4-6 weeks period. This is normal as new hair shafts are being formed and old ones are pushed out.
In males with male pattern baldness (MBP) or androgenic alopecia (hormonal related hair loss), DHT binds to the follicles and causes hair to gradually thin out. This occurs from the front, back to the crown. There is a wide variation in MBP and is dependent on a number of factors. Medications exists that inhibit the production of DHT such as finasteride (Propecia®).. Minoxidil (Rogaine®), a medication for high blood pressure, can also help stop hair loss. The exact mechanism for by which Minoxidil works is not completely understood. Males can take finasteride and use topical Minoxidil. It is recommended that women not take finasteride due to the high risk of fetal birth defects.
Most accepted hair loss treatments work at best fifty percent of the time. That still leaves millions of people affected by hair loss which affects their self esteem and quality of life. It is here where platelet rich plasma may provide hope for thicker hair and new hair growth - a treatment that does not involve surgery or medications.
