When it comes to finding the best shampoo, you don't necessarily get what you pay for, finds STEPHEN LEWIS

BECAUSE you're worth it, gush the adverts, as a model runs her fingers through her long, luxuriously silky hair.

It's a clever association of ideas. Spend enough, goes the message, and you, too, could have hair (and, by implication, a face and figure) like this.

Beauty is big business. The shelves of your local supermarket and pharmacist are filled these days with anti-ageing creams and gels, not to mention a breath-taking array of expensive shampoos promising to put life, body, softness and shine back into your hair.

Now, however, a cool-headed investigation by consumer champions Which? magazine has revealed that if you do splash out over the odds on an expensive shampoo, much of what you're getting for your money is packaging, advertising, and a sophisticated fragrance.

Which? tried out 22 shampoos at a top hair research laboratory, using ponytails of real hair that was either dry and damaged, or artificially dyed. The aim? To find out how shampoos designed especially for dry or coloured hair compared to non-specialist shampoos for "normal" hair.

Ten of the shampoos tested were "specialist" products that claimed to improve dry or damaged hair, while a further ten claimed to prevent dyed hair from fading in colour by cleaning hair gently and/ or protecting it with sunscreen. The other two were normal-hair shampoos, Tesco's own-brand Wheatgerm and Cornsilk shampoo (68p for 750ml)and Pantene Pro-V Classic Care (£1.99 for 200ml), which made no claims to be especially effective for dry or coloured hair.

The results? The "normal hair" Tesco and Pantene shampoos worked just as well as many of the specialist shampoos at both moisturising and protecting against colour fade.

When it came to protecting dyed hair against loss of colour, the Tesco shampoo was as good as or better than shampoos costing up to 30 times as much - namely Charles Worthington Dream Hair (£5.95 for 200ml) and the salon-only Redken Colour Extend (£9.95 for 300ml). "The Tesco product, which doesn't contain a sun filter, was just as effective at protecting hair in UV light, and better at preventing fade during our washing tests," notes the report.

Shampoos labelled as being for dry and damaged hair often claim to "moisturise" or "hydrate". Many also claim to improve softness and shine. Of those tested, Elvive Nutritive (£3.19 for 300ml) and Umberto Giannini Urgent Repair Moisture Booster (£4.15 for 250ml) received top marks for both softness and ease of combing, the report notes.

But the Tesco wheatgerm shampoo left hair just as soft and far easier to comb than some other, far more expensive rivals, such as the salon-only Paul Mitchell Instant Moisture Daily (£5.25 for 250ml), Boots ProVitamin Dry/Damaged Hair (£1.49 for 250ml) and Pantene Pro-V Smooth and Sleek (£1.99 for 200ml).

The message, says Helen Parker, editor of Which?, is that you shouldn't necessarily assume that expensive specialist shampoos are necessarily going to be head and shoulders above the rest.

"Some were less effective than a Tesco own-label shampoo, which makes no claims at all," she said.

"Shampoos for normal hair often worked just as well as specialist products that made particular claims. And the cheaper shampoos did a better job than the two over-priced, salon-only products - Redken Colour Extend and Paul Mitchell Instant Moisture Daily.

"It seems that much of what you pay for is packaging, advertising and a sophisticated fragrance."

Updated: 09:55 Thursday, March 06, 2003