They want to be pert, they want to be taut, they want glossy manes into their 60s. And they want balms, dyes and depilatories that will help them achieve it. Some might dismiss it as vanity, but society's increasing preoccupation with looks is fuelling a booming business in cosmetic drugs, or 'cosmeceuticals', worth $3.4 billion last year in the United States alone.

Cosmeceuticals lurk in the shadowy ground between drugs and cosmetics. Allergan's Botox, which flattens furrowed foreheads, is one example. Merck's Propecia for balding pates is another, as are off-the-shelf skin creams with active biological ingredients.

Those who add a prescription cosmeceutical to their morning routine can have real hope of seeing results. But the enticing skincare aisles of your local drugstore tell a different story: dermatologists confess that some 90% of ingredients in anti-ageing creams are little more than overpriced petroleum jelly. Why, when you slather on jelly for wrinkles, do you need to smear on a healthy dose of scepticism?

Cosmeceutical manufacturers must shoulder much of the blame, for trying to sidestep drug regulations. The US Food and Drug Administration (FDA) defines drugs as agents intended for use in the diagnosis, cure, mitigation, treatment or prevention of disease, or that affect the structure or function of the body. Cosmetics escape the rigorous trials demanded of a drug because they are assumed only to alter our appearance. But the system falls down for cosmeceuticals, because it is the manufacturers — not the FDA — who decide whether a product is classed as drug or cosmetic. A cream that claims to cure eczema is a drug; if it claims to promote healthy skin, it is a cosmetic. This bizarre situation means that, although some cosmetics companies have excellent R&D arms, many are dissuaded from finding genuinely active ingredients, or advertising their properties if they do, for fear of having to undergo expensive drug trials. This also fuels the pseudo-science that is used to hype cosmetics.

This state of affairs must change. Cosmeceutical manufacturers should show that their ingredients genuinely work, or find some that do. The FDA should revise its outdated regulations to enforce this, so that all biologically active ingredients, whether drugs or cosmetics, have to prove their worth. Consumers are helpless to tell fact from fiction in today's non-prescription creams, so there is a market for prescription drugs with proven cosmetic powers. A few pharmaceutical and cosmetics giants, including Pfizer and L'Oreal, are embarking on research to fill this niche. Some people might argue that pharmaceutical companies should concentrate on curing deadly diseases, not feeding society's body paranoia. But if there is money in the beauty parlour, they are likely to pursue it (see page 990).

Perhaps a more thorny dilemma will face doctors who have to decide whether to prescribe cosmetic drugs to patients who demand them for wrinkles or baldness. As with any non-essential therapy, national or private health insurers can exclude them from coverage. But doctors and medical ethicists must consider whether they have the right to refuse a prescription to patients willing to pay.

The dilemmas thrown up by cosmeceuticals will become more pressing as biologists reveal the secrets behind wilting skin and barren follicles — and the molecules that might revamp them. Our attitudes are outdated. Consumers should demand more from their $20-a-pot unguents. And when 'real' cosmeceuticals are created, doctors, industry and regulators should work together to ensure that they are effective and accessible.