Consultant in chemical pathology and metabolic medicine, Leeds General Infirmary
Balding is not a disease. It is a normal process that occurs in men and women with the onset of puberty - the hormone testosterone is necessary for balding. This was shown in the 1940s by James Hamilton, who carried out tests on young men who had been castrated, quite often in pushbike accidents.
As women release less testosterone than men, they will not normally notice any hair loss until they are in their seventies. You have to lose more than 50 per cent of your hair before you become aware of thinning.
Once the hair-loss process has started, it is impossible to reverse it. Treatments available today can thicken the hair bulk only by 20 to 30 per cent, which is not enough. But this does not deter men from spending a lot of money on hair transplants or treatments.
In hair-transplant surgery, cylinders of skin containing hair roots are taken from above the neck and transplanted to the top of the head. This should thin out the hair on the back of the head and encourage the top to thicken and grow. But if it is not done properly the hair can sprout in all directions. Hair roots that have been planted in nice rows, like an orchard, will look awful when the sun shines through them.
Some of the treatments available in the United States for balding are used in this country for other reasons. Finasteride, which was originally developed to treat prostate problems, is now available on prescription in the US. Tests have already shown that it can stabilise hair loss at 90 per cent. It is also thought that it might produce a small reversal of the balding process - but it is not yet known whether finasteride or minoxidil, another hair-growth drug prescribed for balding in the US, will ever be able to make any real difference. They would also cost around Pounds 50 a month to prescribe.
There are no side-effects associated with either drug, but there is not enough evidence to be sure that they are safe to be used for purely cosmetic reasons. Although many men want these kinds of drugs to be available on the National Health Service, we should wait ten or 15 years to be sure that they are useful.
Women and men should simply be able to accept the fact they are losing their hair.
Interview by Jennifer Currie.