Hair loss is a natural daily occurrence in both men and women. Because hair follicles are genetically programmed to grow, rest and shed in a cyclical fashion, we rarely notice the loss until the cycle is altered by other factors such as genes, hormones and age. An average head of hair has more than 110,000 hairs. This works out to be around 220 hairs per square centimeter. Because of the cyclical nature of hair growth, people can lose 50 to 150 hairs a day. Thinning starts to show when hair density falls to about 100 hairs per square centimeter. This is when hair loss can become a problem.
Genes, hormones and age are the three most important factors in determining a person’s rate, density and strength of hair growth. Hair loss is a very individual occurrence and some people start balding as early as in their teenage years. Genetically, a person must have inherited specific genes from at least one parent to suffer from hair loss. The same hormones that cause acne and beard growth can also cause hair loss.
The most common form of hair loss is known as “Male Pattern Baldness” (androgynous alopecia). In Male Pattern Baldness, the hormone DHT (Dihydrotestosteron) acts on genetically vulnerable follicles to produce progressively thinner, shorter, more brittle hair with a weaker shaft. Over time, the thinning hair may eventually die out completely.
This form of hair loss usually affects a certain area of the head, such as the front or crown, while leaving areas like the back of the head and sides relatively untouched. A typical result of Male Pattern Baldness is a horseshoe of hair growth around the bald patch. Because the remaining hair is unaffected by the DHT, it keeps its characteristics and continues growing even after being transplanted to thinning areas.
Hair loss in women is also related to genetics, hormones and age. Although the hair loss patterns usually look and act different in men and women. Female Pattern Baldness often affects a larger area and is slightly more diffuse than for men.