If the internet is a reliable barometer of the human psyche, it would appear that our species has entered the 21st century with a greater concern than ever about its follicles. Seek out references to “road accidents” on the web and the search engine Google comes up with 439,000 pages. “Sexual equality” barely musters 269,000 mentions. But type the phrase “hair loss” and 956,000 web pages are instantly available.

In a society that places great value on youth and appearance, it’s hardly surprising that avoiding baldness is important for so many people. But how do you go about keeping your hair on when all about you are losing theirs?

Hair follicles go through cycles of activity. After a period of growth that can last several years (the hair on our heads grows about a centimetre a month) comes a dormant phase. The hair develops a clubbed base (hair is dead tissue, like horn or finger nails) which holds it in place while the follicle shrivels. But when the follicle becomes active again, it produces a new hair which pushes out the old one.

In other mammals, the activity of the hair follicles in the scalp is synchronised, with major moults occurring at certain times. But, in humans, each of our 150,000 follicles has its own agenda, so that there is a small but steady moult of about 50 to 100 hairs a day.

However, this regular cycle of growth, rest and renewal can be disrupted by a variety of factors, from disease to diet and the use of drugs in cancer therapy. Acute but temporary alopecia - the medical term for baldness - can follow fever or childbirth, and scar tissue resulting from injury will never again grow hair.

But far and away the most common cause of baldness is the hormonal change that comes with maturity. So-called “male pattern baldness”, characterised by frontal hair recession and thinning over the crown, occurs to some extent in most men of European origin (it is rare among Asians, Africans and native Americans), beginning at any time after puberty.

Like its female equivalent (women’s hair tends to thin rather than recede), it is a hereditary condition, stemming from either the father’s or the mother’s side of the family. And in both cases male sex hormones are to blame - the same hormones that cause men to grow body hair. The hormones don’t actually kill follicles but cause them to produce much finer hairs, a barely visible down which replaces the sturdy, pigmented hair that society so values.

Given the cause of hereditary baldness, the myriad cures that have been a source of income for the unscrupulous for thousands of years were never going to work. Today a drug, Minoxidil, can stimulate hair growth in a small proportion of patients, but the potions and pills sold down the ages were at best ineffectual and at worst dangerous.

In the 19th century, for instance, “Whittem’s rosemary and cantharidine hair tonic” offered all pain and no gain, since cantharidine causes skin to blister on contact.

At the beginning of the 20th century, elaborate technological equipment joined the array of quack cures waiting to trap the unwary or the desperate, and one of the more widespread involved the use of a vacuum pump and a helmet sealed with a rubber gasket.

While scalp vacuuming was supposed to suck impurities from clogged follicles and draw trapped hair through the scalp, other devices used the new “Farradaic” electrical current to stimulate follicles. Vacuum and electro stimulation are still offered in different guises in expensive health clinics.

A more effective (if hardly more comfortable) treatment for baldness is hair transplantation. Typically, this involves cutting patches of skin and follicles about the size of a pea from the back of the head and grafting them on to the front. But the technique can result in a “doll’s hair” or “corn row” appearance that attracts as much derision as a toupee.

Minigrafts and micrografts, in which one or two hairs are transplanted at a time (several hundred or more per session), avoid this. But the technique is both tedious and time consuming and, as with any transplant, depends on the patient having sufficient hair-bearing skin in the first place.

When this is not the case, it’s time for scalp reduction. This involves removing sections of bald scalp and stitching areas of hair growth closer together. If the skin of the scalp is too tight for this, then the patient may opt for tissue expansion, in which a silicone balloon is placed beneath the scalp and inflated over time.

While thousands of men are prepared to undergo such treatment to gain hair - and avoid staffroom sobriquets such as Baldilocks, Bonehead and Chrome Dome - thousands of women go through similar tortures in order to remove it. If that weren’t enough of a paradox, consider this: the very sex hormones that cause men to replace sturdy scalp hair with down also cause down on women’s bodies to be replaced with visible hair.

Until we learn to leave our hair alone, we will, it seems, be martyrs to our follicles.