Androgenic Alopecia is also known as hereditary balding, male pattern baldness, and androgenetic alopecia. It is the most common form of hair loss. It has a higher incidence in men than in women mainly due to sex hormones.

Androgenic Alopecia is characterized by thinning of the hair on the scalp as opposed to follicular hair loss. Male pattern hair loss usually doesn't present itself until after puberty when the male hormones are really elevated. This is when someone with a genetic predisposition to balding will start to notice their hair thinning. Studies have shown that around half of all caucasian men over the age of 40 experience some form of hair loss. The occurence and severity in other cultures seems to be much lower, but still present.

Androgens, specifically testosterone and dihydrotestosterone or DHT, are necessary to activate the genes in the scalp to create hair loss. Your genes modify the way the scalp responds to circulating androgens in the blood.

Three key features of alopecia include:

1. Follicular miniaturization. Hair follicles are full of androgen receptors and when androgens are present, genes that shorten the anagen phase are activated. Then the follicles may shrink or become miniaturized. Eventually the follicles shrink and nonpigmented vellus hairs replace pigmented terminal hairs.

2. Males with alopecia have a reduction in terminal to vellus hair ratio and exhibit typical distribuion of hair loss

3. Areas of inflammation

It is widely believed that a variety of genetic and environmental factors contribute to androgenic alopecia. Even though researchers are hard at work studying the many possibilities, most of these remain unknown. Many scientists point to the maternal side of the equation for the link to the balding gene, but there seems to be conflicting evidence. There are other genes found to be involved with hair loss as well. In 2009, Japanese researchers identified a gene called Sox21, which they say is responsible for hair loss in people.

Scientists are just beginning to discover the complex map of the human genome. Mapping this enormous puzzle will take decades, so any evidence of the gene or genes responsible for hair loss won't be completely evident for years to come.

Lifestyle seems to be a smaller factor in pattern baldness in males and females alike. It has been shown numerous times that during the hunter-gatherer times of our ancestors, baldness was almost none existent. Some point to our diet, or to modern western diets today, may be the main contributing factor. Many American diets today lack many vital nutrients, from fruits and vegetables, that many scientists believe could have an effect. Our diets today contribute to a whole host of other diseases that male pattern baldness doesn't seem that unlikely. Men who exercise may have higher testosterone levels than their non exercising counterparts, which may be another contributing factor.

Another interesting fact is that different races are affected by pattern baldness differently. The severity of the condition tends to be the highest among caucasian men. African Americans and Asians round out the second spot, followed by Native Americans. The actual reason for this variance among races is still misunderstood in the scientific community, but it most likely points to genetic traits confined to one specific race.

With age comes the likelihood of this condition. The older you get, the more likely you are to it. Even though hormone levels drop off after age 30, the likelihood of being diagnosed with this condition increases.