What is DHT and how is it involved in hair loss?
DHT stands for dihydrotestosterone. This is the active form of the male hormone testosterone. It has been suggested that high DHT levels in genetically predisposed hair follicles initiate baldness. It is this chemical conversion from testosterone to dihydrotestosterone that is blocked by hair restoration products, such as finasteride, which is a prescription medicine and the active ingredient in Propecia, another prescription medication to treat hair loss. Finasteride blocks the formation of active testosterone and allows those hairs predisposed to inactivity to become active again and make new hairs.

What is the relationship between genetics and hair loss?
Although not the primary cause of male-pattern hair loss, genetics does have a significant role in male-pattern hair loss. It is, however, polygenic, in that there is more than one factor at work. It is unclear whether having an affected mother or an affected father predisposes descendants to greater risks.

Can hair loss occur in young adults?
Male-pattern hair loss can occur as early as 15, although it typically begins anywhere from the 20s and early 30s. Familial history may help determine if this is going to occur, as parents with a history of early-onset male-pattern hair loss may increase the risk for this to occur in descendants. Alopecia areata and telogen effluvium, two other forms of temporary hair loss, can occur in children as young as one year of age. Other precipitating factors may also be involved.

What can be the cause of a sudden loss of a large mass of hair?
Stressors to your system, such as illness, high fever, pregnancy, extreme weight loss or gain, and drug use, can cause temporary hair loss. This occurs when the ratio of growing to resting hairs is upset and more of the growing hair shifts into a resting phase. A greater quantity of normally sleeping hairs falls out, prompting a visit to the dermatologist. This type of hair loss is temporary and full regrowth should be expected.

Do shampoos and other hair products cause hair loss?
An allergic reaction to any constituent in shampoo or hair products can cause hair loss. Shampoos are designed to be as safe as possible, although there is always someone who will react to them. Caustic hair dyes, straighteners, and other products can certainly cause inflammation of the scalp and result in hair loss.

Can my hairstyle cause my hair to fall out?
Certain hairstyles can contribute to hair loss, most notably styles involving tight braids or pull-backs. This form of hair loss is called traction alopecia. This occurs when the hair is pulled tightly back and fastened at the base of the skull, or braided into tight braids or rows. Exposure to this type of hairstyle over long periods can result in a scarring alopecia, with no potential for regrowth.