Baldness gets thin explanation Hair: Researchers agree on how hair grows but have yet to discover the definitive reason for male-patterned baldness.

When Hippocrates, the Greek physician who is considered the father of medicine, discovered he was losing his hair, he coated his scalp with an ointment of opium and essence of roses.

His hair failed to grow back.


He then tried a formulation of acacia oil and wine. Again, no luck. But Hippocrates earned the distinction of being the first to document the step-by-step course of male-patterned baldness, which was given the Greek name alopecia. In his honor, his colleagues named the fringe around a bald pate a Hippocratic Wreath.

Twenty-four centuries after Hippocrates, the cause of male baldness remains elusive. Researchers still do not fully understand the processes that kill hair follicles and lead to hair loss. But drugs now on the market and in the pipeline may slow baldness, and perhaps prevent it.


Baldness is problem not of hair but of hormones. A healthy adolescent male starts with about 120,000 hairs on his scalp. Each hair has a semi-hollow core, surrounded by a layer of long, thin fibers, and then layers of dead cells filled with the same protein that makes fingernails and toenails and the outer layer of skin. And each hair is rooted within a follicle.

A hair typically will grow a half-inch a month and continue growing for three to seven years. It then enters a rest phase of two to three months, after which the hair falls out and a new hair begins to grow in the same follicle.

Baldness begins after age 15. The cause is generally agreed to be testosterone, the hormone that influences male characteristics from sex drive to aggression. An enzyme called 5-alpha reductase -- which is produced in the largest concentrations in the prostate and scalp -- converts some of the testosterone to dihydrotestosterone, or DHT. DHT can in turn cause hair follicles to begin to atrophy.

Scientists agree that patterned baldness is inherited from either parent. But they are unanimous about little else.

The latest debate erupted last year when Dr. Robert Smart, a researcher at North Carolina State University, reported that the female hormone estrogen harmed hair follicle growth, and hence played a role in baldness.

Published in the Proceedings of the National Academy of Sciences, Smart's research entailed clipping off the hair of three groups of mice. One group then was coated with a chemical that arrested hair growth for a prolonged period. Two control groups received chemicals that had a minimal effect.

When Smart treated the denuded skin of the first group with an estrogen-blocking drug, their hair follicles responded. Within 10 weeks, the mice produced coats so thick they were indistinguishable from untreated mice. Smart says the estrogen blocker prevented normal estrogen stimulation and hair growth was the result.

Other researchers say his findings with mice have no bearing on humans, in part because mice do not develop male-patterned baldness.


"This animal data does not apply to male- or female-patterned hair loss," says Dr. S. Elizabeth Whitmore, a dermatologist at the Johns Hopkins School of Medicine and head of a research team studying a prospective baldness inhibitor now in clinical trials.

Whitmore says she knows of no data to support a theory that estrogen blockers play a major role in preventing baldness. One significant example of contrary evidence, she says, is the case of a 28-year-old man who lacks functioning estrogen receptors but has early-stage baldness, a case reported in the New England Journal of Medicine.

According to Whitmore, the young man is a medical rarity, because estrogen receptors were thought necessary to life-essential processes.

"No matter how much estrogen they pumped into this guy, it had absolutely no detectable effect," she says. Since the patient had patterned baldness but couldn't process estrogen, he seems proof that estrogen blockers alone cannot prevent baldness.

But the debate over baldness includes a long history of clashing theories.

The mummy of Ramses II, who tradition says was the pharaoh at the time of the Israelites' Exodus from Egypt, shows him as mostly bald. His condition would have been apparent to his worshippers were it not for his shoulder-length wig. He was among the first in a long line of rulers who resorted to camouflaging baldness.


Julius Caesar brought to prominence the hair piece, in his case the laurel wreath. Suetonius writes in his "Lives of Caesar" that the emperor considered baldness so troubling a disfigurement that he combed his hair forward from the crown, thereby becoming an illusion stylist.

And male-patterned baldness has been attributed to an encyclopedic list of causes. At the top is the hat, which was attacked for allegedly choking off the blood supply to the scalp. A second theory indicted the hat for allegedly creating a hothouse atmosphere in which bacteria and parasites could multiply.

Then in 1910, a study of more than 300 men in Boston claimed to find that exposure to the sun was a cause of baldness. The more extended the exposure, it was said, the faster the hair loss. Men were advised to wear hats even on cloudy days. The hat was back.

Not until World War II did scientists focus on hormones. One study in the 1940s focused on a prison population of bald men who were injected with estrogen. According to accounts in the popular press, the hormone restored hair growth in some cases but also shifted bass voices to sopranos, produced enlarged breasts and reduced libido.

In the 1960s, researchers at the University of Pennsylvania had equally discouraging results from use of testosterone. In a sample of 21 elderly men, the application of testosterone produced a thick crop of hair on forearms and in armpits but relatively little on the scalp, and at the cost of increased risk of prostate cancer and heart disease.

There is a newer generation of treatments, led by a new, albeit imperfect drug marketed under the name Rogaine. Its major ingredient is minoxidil, originally developed as a treatment for high blood pressure.


Whitmore says that the results range from excellent to no effect whatsoever, and that no one understands precisely how minoxidil works. Dr. Marty Sawaya, a dermatologist at the University of Florida, predicts that its efficacy will improve if the Food and Drug Administration approves an increase in the concentration of minoxidil to 5 percent from 3 percent.

Sawaya is leading the clinical trials of finasteride, a second hair-loss inhibitor. Finasteride prevents testosterone from being converted into DHT, which causes follicles to begin to atrophy.

As in the case of minoxidil, finasteride was originally developed for other purposes -- in this case, to treat prostrate enlargement. It is still awaiting FDA approval for use in treating baldness.

Sawaya suggests that a mix of minoxidil, finasteride and another drug which is still in the early stages of development may have a greater effect than any of them used alone. And will that be the definite cure for male-patterned baldness?

"Frankly," says Sawaya, "we don't know."

Pub Date: 1/22/97