They say you have to suffer to be beautiful, but now a string of worrying studies linking hair dye with cancer is making women more cautious about picking up a pack at the supermarket.

Andie MacDowell tells us she uses colorant to cover her grey “because I’m worth it”. Last month, however, a study by Yale School of Public Health, suggested that women who used dark hair dyes more than nine times a year doubled their risk of developing follicular lymphoma, a form of leukaemia. For those who started dyeing their hair in the 1970s, the risk rose further, probably due to chemicals that are now banned.

In 2001, a study in the International Journal of Cancer found that women who used permanent hair dyes regularly for 15 years or more were three times as likely to develop bladder cancer as women who didn’t dye their hair. And earlier this year, the World Health Organisation reported evidence that exposure to the chemicals in hair dyes can increase the risk of bladder cancer for male hairdressers and barbers. It did note that there was insufficient evidence to say that this risk extended to people who dye their own hair — but it also suggested that dark hair dyes are especially rich in carcinogenic chemicals.

If all this isn’t quite enough to turn your hair white, it certainly makes you wonder if you should let it go grey. Should we panic? Jamie Page of the Cancer Prevention and Education Society, urges caution: "For some time there have been known links between hair dyes and cancer. People should be aware that many chemicals in consumer products have not been adequately tested and evaluated by independent regulators for safety."

The cosmetics industry, however, insists that the products we use are perfectly safe, particularly after many of the carcinogenic chemicals used in hair dye were banned in the late 1970s, with a further 22 outlawed in 2006. The Cosmetic Toiletry and Perfumery Association, an industry body, says: “Hair colorants and the dyes they contain are among the most thoroughly researched of all products on the market.”

Hair dyes are, of course, big business, with about 45m salon treatments a year in the UK and a further 50m units of home hair colour sold, so you might be sceptical. On the other hand, it is worth bearing in mind that the types of blood cancer linked to hair dyes are normally non-aggressive and extremely rare. Only 15.4 women in 100,000 develop these strains and they are unusual in the under-40s.

Henry Scowcroft, senior science information officer at Cancer Research UK, says: “Women who dye their hair should not panic. Although this study did find a link between some types of hair dye and certain types of lymphoma, the increase in risk was extremely small and applied mainly to permanent dyes available before 1980.”

This doesn’t mean colorants are harmless. They contain strong chemicals that can trigger allergies, even potentially fatal ones. In 2000, Narinder Devi, 39, died of anaphylactic shock, an extreme allergic reaction, after using a permanent black hair dye at home in Birmingham. She had previously had an irritated scalp when dying her hair, but thought it was due to ammonia in the product, so she chose an ammonia-free product the next time. In fact, the redness and tingling that she apparently suffered were almost certainly a warning signal that she was becoming sensitised to certain chemical colorants (see below) that were penetrating her skin and getting into the bloodstream. Her immune system was priming her body for the final, fatal attack. Although this was an extremely rare case, it highlights the need for caution when choosing permanent dyes.

Perhaps the most controversial ingredient in modern hair colorants is p-Phenylenediamine (PPD). Found in permanent dyes, it is linked to rare but sometimes severe allergic reactions. Its use in hair dyes is banned in Germany, France and Sweden.

So, what can you do to minimise even the slightest risk involved in dyeing your hair? To avoid a PPD allergic reaction, always patch-test colour first. You might also want to consider swapping your permanent colour for one that washes out in six weeks or so, or swapping your tint at the salon for highlights or lowlights, which are applied on foils, so don’t touch the scalp. There are also a few chemical-free dyes available, such as Logona Herbal Hair Colours (£8.90; spiritofnature.co.uk ). They aren’t permanent, and are relatively expensive, but they come in a good range of shades and shouldn’t hurt the environment or your health.

WHAT’S GOOD OR BAD

The following chemicals have been known to cause rare allergic reactions in some people

2,4-Diaminophenol

m-Phenylenediamine (also called meta-Phenylenediamine or MPD)

p-Phenylenediamine (also called para-Phenylenediamine or PPD)

N-Phenyl-p-phenylenediamine (also called N-Phenyl-para-phenylenediamine)

Toluene-2,5-diamine Variants of these chemicals may have hydrochloride, HC1 or sulphate as suffixes. They may also cause allergic reactions. Hair dyes containing these ingredients will have warnings on the packet. You should always patch-test before use, even if you have used them before, as allergies to PPD can develop suddenly, without warning

Thankfully, natural hair dyes have moved on from henna treatments. Try these for peace of mind

For the home hair-dyer, Tints of Nature and Naturtint are free from ammonia and parabens. Find them at your local health-food shop.

If you would rather leave it in the hands of the experts, head to Aveda or Daniel Field for plant-based dyes.

London hairdresser of the year Karine Jackson (020 7836 0300) is renowned for the organic colour system she uses on clients. Its hair dye has the lowest possible percentage of PPDs.

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