women's alopecia hair loss

what do charles darwin, michael jordan,and yoda have in common? they, like many other historicaland fictive individuals, are bald, in some cases by their own choice. for centuries, a shining dome has beena symbol of intelligence, but despite this, many balding peoplestill wish their hair would return. scientists have long pondered, "why do some people lose their hair,and how can we bring it back?" the full-headed among us have about100,000 to 150,000 hairs on our scalps, and scientists have discovered two thingsabout this dense thicket.

firstly, the sprouting hair we seeis mostly made up of keratin, the protein leftover from dead cellsthat are forced upwards as new cells grow beneath them. secondly, the structures that drive hair growth are called hair follicles, a network of complex organsthat forms before we're born, and grows hair in an everlasting cycle. this cycle has three main phases. the first is anagen, the growth phase,

which up to 90% of your hair folliclesare experiencing right now, causing them to push up hairat a rate of one centimeter per month. anagen can last for two to seven years,depending on your genes. after this productive period, signals within the skin instructsome follicles to enter a new phase known as catagen, or the regressing stage, causing hair follicles to shrinkto a fraction of their original length. catagen lasts forabout two to three weeks and cuts blood supply to the follicle,creating a club hair,

meaning it's ready to be shed. finally, hairs enter telogen,the resting phase, which lasts for ten to twelve weeks, and affects about 5-15% of your scalp follicles. during telogen, up to 200 club hairscan be shed in a day, which is quite normal. then, the growth cycle begins anew. but not all heads are hairy, and, in fact, some of them growincreasingly patchy over time

in response to bodily changes. 95% of baldness in men canbe attributed to male pattern baldness. baldness is inherited, and in people with this condition, follicles become incredibly sensitiveto the effects of dihydrotestosterone, a hormonal product made from testosterone. dht causes shrinkage in these overly sensitive follicles, making hair shorter and wispier. but loss isn't sudden.

it happens gradually, along a metricknown as the norwood scale, which describes the severity of hair loss. first, hair recedes along the temples, then hair on the crown begins to thinin a circular pattern. at the highest rating on the scale, these balding areas meet and expand dramatically, eventually leaving only a ringof sparse hair around the temples and the back of the head. genetics isn't all that drives hair loss.

long periods of stress can releasesignals that shock follicles and force them into the resting phase prematurely. some women experience thisafter childbirth. follicles might also lose the abilityto go into anagen, the growth phase. people going through chemotherapytreatment temporarily experience this. but while balding may look permanent, scientific investigation has revealed the opposite. below the skin's surface, the roots that give rise to our hairactually remain alive.

using this knowledge, scientists have developed drugsthat shorten the resting phase, and force follicles into anagen. other drugs combat male pattern baldness by blocking the conversion of testosterone to dht so that it doesn't affect those sensitive follicles. stem cells also play a role in regulatingthe growth cycle, and so scientists are investigatingwhether they can manipulate the activity of these cells to encouragefollicles to start producing hair again.

and in the meantime, while scientists hone their hair-reviving methods, anyone going bald, or considering baldness, can remember that they're in great company.