So colourful and exotic is the list of substances that have been claimed to heighten sexual appetite that it is hard not to feel a twinge of disappointment on first beholding the latest entry - a small, white plastic nasal inhaler containing an odourless, colourless synthetic chemical called PT-141. Plain as it is, however, there is one thing that distinguishes PT-141 from the 4,000 years' worth of recorded medicinal aphrodisiacs that precede it: this one actually works. And it could reach the market in as little as three years.

The full range of possible risks and side effects has yet to be determined, but already this much is known: a dose of PT-141 results, in most cases, in a stirring in the loins in as little as 15 minutes. Women, according to one set of results, feel 'genital warmth, tingling and throbbing', not to mention 'a strong desire to have sex'.

The precise mechanisms by which PT-141 does its job remain unclear, but the rough idea is this: where Viagra acts on the circulatory system, helping blood flow into the penis, PT-141 goes to the brain itself. 'It's not merely allowing a sexual response to take place more easily,' explains Michael A Perelman, co-director of the Human Sexuality Program at New York Presbyterian Hospital and a sexual-medicine adviser on the PT-141 trials. 'It may be having an effect, literally, on how we think and feel.'

Creepy:

Two years earlier, and just three years past its start-up, the company had bought the rights to develop a substance called Melanotan II. Originally isolated by University of Arizona researchers looking for a way to give Caucasians a healthy, sunblocking tan without exposing them to dangerous ultraviolet rays, Melanotan II achieved that and more: it also appeared to facilitate weight loss, increase sexual appetite and act as an anti-inflammatory, too. Quickly dubbed 'the Barbie drug', Melanotan II seemed too good to be true.

In fact, it was too good to be good. A drug with so many effects, Palatin decided, was not an effectively marketable one. So Palatin's researchers set out to isolate the individual effects in the laboratory, experimenting with variations on Melanotan II's molecular theme. The compound that became PT-141 was one of the first variations examined.

Creepier:

'I see a lot of couples in my practice who don't know how to relax,' says Leonore Tiefer, a professor of psychiatry at New York University School of Medicine. 'That's fine - it's a big asset to them in their corporate lifestyle, where they can work 80 hours a week. They're trained to multi-task. Well, it doesn't seem that that is really doable when it comes to sex. And they're angry about that: they need it to be doable because they only have their five minutes.'

The five-minute meaningful sexual encounter: if ever there was a holy grail for the age of the tight-wired global economy - with its time-strapped labour force and its glut of bright, shiny distractions - that is it. And if ever there was a reason to be wary of the pharmaceutical industry's designs on the market for sexual healing, say critics such as Tiefer, it's the attractiveness of that simple-minded ideal.

And here's a fine out-of-context quote:

'He notices it's there, and he grooms it to detumescence,' says Annette Shadiack, Palatin's executive director of pre-clinical development. 'And then it happens again.'