By FIONA MACRAE

Last updated at 21:10 19 June 2007

It takes cleanser, moisturiser, make-up and a favourite lipstick to ensure the average woman is ready to face the world.

But a daily routine like this leaves her with more than a polished appearance.

She also absorbs almost 5lb of chemicals through her skin every year.

Some of the man-made compounds have been linked to cancer, while others may irritate the skin or even cause it to age prematurely.

Biochemist Richard Bence warned that the chemicals found in everyday beauty products could be doing untold damage.

Mr Bence, who has spent three years studying the ingredients in cosmetics and toiletries, said: "There is a growing amount of research questioning the ingredients found in conventional beauty products.

"We really need to start questioning the products we are putting on our skin and not just assume that the chemicals in them are safe.

"We have no idea what these chemicals do when they are mixed together. The effect could be much greater than the sum of the individual parts."

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Among the chief chemical suspects are parabens - preservatives widely used in skin and hair products, including soap, shampoo, deodorant and baby lotion.

Capable of stopping bacterial growth, parabens are also thought to mimic the effects of the female sex hormone oestrogen, which is known to help tumours grow.

Traces of the chemical have been found in breast tumour samples but the link with cancer is, however, hotly disputed.

Sodium lauryl sulphate, which helps soap, shampoo, shaving foam, toothpaste and bubble bath lather up, can irritate skin.

Other potential irritants include benzyl alcohols, which are used to scent and preserve perfume, makeup and hair dyes.

Cocamide MEA, which binds the ingredients of many moisturisers, is also a suspect.

The average woman absorbs 4lb 6oz of chemicals from toiletries and make-up every year, the industry magazine In-Cosmetics recently reported.

Mr Bence, who last year founded a website which specialises in organic beauty products, said absorbing such chemicals is more dangerous than swallowing them.

"If your lipstick gets into your mouth, it is broken down by the enzymes in saliva and in the stomach.

"But if the chemicals get straight into your bloodstream, there is no protection."

Sodium lauryl sulphate is among chemicals banned from health and beauty products certified as organic by the Soil Association.

Soil Association spokeswoman Clio Turton suggested beauty enthusiasts should try to reduce the number of products they use each day.

"Many women are using over 20 different products a day, bombarding themselves with hundreds of different chemicals - is that eyelash conditioner really essential?" she said.

The warning follows research showing nine out of ten women apply make-up past its use-by date.

The Royal College of Optometrists warned that old ipstick or mascara could be a "hothouse" for bacteria. Cosmetic and toiletry manufacturers insisted that their products are safe.

Dr Christopher Flower, of the Cosmetic, Toiletry and Perfumery Association, said: "There is no reason at all to be worried about the safety of any products.

"They are all covered by EU-wide regulation which requires them to be safe - there are no ifs and buts about it.

"The cocktail effect of chemicals is an urban myth.

"We do know how different chemicals react individually and can predict how they interact with each other and this is taken into account when the safety of products is assessed."