Let's face it, when it comes to shampoo we are mugs. We stack our bathroom shelves until they look like the toiletries section of a small supermarket. We switch brands like philanderers unable to settle down, constant in the hope that tomorrow will bring something better. We think we are buying a cleaning product but, if we are honest, we know we're buying a dream: the one that says if our hair just had more body or shine, or if it were only less flyaway, we could be happier/ healthier/ spiritually more complete human beings (tick as appropriate). From the shampoo makers' point of view, we are there for the taking. And they know it.

Nowhere has this been more evident in recent years than in the case of Pantene Pro-V and Elida Gibbs Organics (note the names: one pseudo-scientific and pronounced in a faux-French way, the other suggestive of organic farming or yoghurt). These "health" shampoos - which sell themselves on the strengthening and revitalising properties of special additives promising the elusive bounce/ shine etc - have risen without trace. It is barely three years since the "vitamin-enriched" Pantene was launched in Britain and it's already the top brand. Organics - which boasts a "root-nourishing" amino acid called Glucasil - was the country's second most popular brand in July, despite the fact it was only launched in June last year.

It would be nice to think that they'd both taken the paying public by storm because they were revolutionary advances in haircare. But that's not quite the case. Take Pantene. Pro-vitamin B5, the basis of its magic ingredient, has been known about since the end of the Second World War, and has been widely used in shampoos. Indeed, less-hyped current brands that use this vitamin in some form or another include Boots Salon System and Alberto VO5. The good news is that pro-vitamin B5 does give hair "body", that is, it draws water into it and swells the strands. The bad news is that it's not, as the little pill capsules in the adverts and on the bottles might suggest, going to make your body glow with health. If that's what you want, you'd do better to take ordinary vitamin pills.

Organics's Glucasil is a genuine novelty. But whether it is capable of "nourishing" (whatever that means) the roots is questioned by many scientists. Unlike those of plants, the roots of hair are, of course, dead.

In short, Pantene and Organics are minor innovations being marketed as major innovations, and backed by huge ad campaigns. In 1994, Procter & Gamble, who make Pantene, spent pounds 10.3m on ads. Unilever, who own Organics, spent pounds 7.8m.

You can see why they do it. They're selling in a saturated market. We all buy shampoo already - pounds 280m worth of it a year - and making us buy more isn't easy. The manufacturers actually did rather well at this in the early Nineties. First they convinced us we needed to use shampoo more regularly, so that now 73 per cent of people wash their hair three times a week or more, compared to just 40 per cent in 1982.

Then they introduced "two-in-ones" which combined shampoo and conditioner. This was a major innovation, and the public recognised it as one. By 1992 combined shampoos had taken 39 per cent of the market. But that kind of growth can't be kept up for ever. Two-in-one sales have since fallen slightly, partly because of worries that they leave damaging silicates on the hair. Hence the need for new technical innovations with which to titillate the ever-hopeful public; hence the way Pantene and Organics have been marketed.

Both are good shampoos. But as Glenn Lyons, clinical consultant to Philip Kingsley and a member of the Institute of Trichologists, says: "Because of advertising, expectations of products these days are too high". If we believe Glucasil or vitamins are the Holy Grail of haircare we are, once again, mistaken.