Two mainstream products – Propecia and Regaine – are widely available over the counter for the treatment of hair loss. While vaunted as miracle cures, both contain drugs that carry the risk of adverse effects. Both are generally cheaper than the more natural alternative products, and some men (and women) may consider the risks worthwhile if the treatment works. In fact, each of these products has around a 30-35 per cent failure rate, which is similar to that of many alternative treatments.

Propecia, a trade name for finasteride, was originally developed for prostate conditions. It reduces levels of testosterone. Aware of the AGA-testosterone connection, Merck & Co soon found that finasteride lowered DHT levels in the scalp, saw its potential in male hair loss and did a number of full-scale clinical trials to test its effects.

The biggest trial to date lasted five years and involved over 1500 balding men, half of whom were randomly given finasteride (1 mg), the other half placebo. After one year, the men taking finasteride had an average of 15-per-cent more hair than the placebo group; this roughly doubled after five years.

These results were trumpeted in major marketing campaigns around the world, but closer inspection, as reported at the 59th Annual Meeting of the American Academy of Dermatology in 2001, showed that, after five years of religiously taking finasteride, more than a third of the men failed to improve or stop their hair loss.

Also, Merck admits that finasteride may not work for a receding hairline at the temples, a major symptom of AGA. Furthermore, you have to keep on taking the tablets; if you stop, you will lose any hair you may have gained.

Adverse effects may include decreased semen production, low libido and impotence. These are commonly seen with the high dosages used for prostate conditions, and are also associated with the relatively low doses recommended for hair loss.

Finasteride is hazardous to unborn children. As it affects male sex hormones, it has the potential to cause serious sexual abnormalities in a male fetus. This danger clearly passes after the menopause, so is finasteride of value to women then? Based on available evidence, the answer is no.

Yet, even the low, recommended 1-mg dosage may not be necessary as studies suggest that a 0.2-mg dose may result in equally significant reductions in levels of scalp DHT – with presumably a lower risk of side-effects. Propecia costs about $47 for 30 1-mg tablets (a one-month supply).

Regaine/Rogaine, trade names for minoxidil, is probably the best-known conventional hair-loss remedy. This property of the compound was accidentally discovered about 20 years ago and, at the time, it was claimed to be 90-per-cent effective.

But clinical trials and expert opinion now suggest that only about 15 per cent of men achieve ‘moderate regrowth’ of hair, 50 per cent have hair-loss delayed and 35 per cent experience no benefit whatsoever. And as usual with these products, as soon as the treatment is stopped, any new-grown hair soon falls out. Similar results are also seen in women.

A 2-per-cent minoxidil solution is available over the counter here in the UK, but a prescription is required for the 5-per-cent version (and should only be used by men).

Bulk-buying Regaine/Rogaine from the Internet or mail-order is more economical, costing about ?100 for a six-month supply.