I've been dying my hair since I was 12 years old, which is kind of sad because somewhere in my mid-20s I went grey, and I'll probably never see my natural hair colour again as long as I live.
Of course, like everything else we all thought was totally harmless, it turns out colouring your hair just might kill you. Then again, maybe not. Some say the evidence linking hair dyes to several forms of cancer including breast and bladder is strong, while others insist it's slim.
Most seem to agree you should not dye your hair when pregnant.
How dangerous is it the rest of the time? The short answer is: people have no fucking idea.
More natural options do exist if you get freaked. But even Aveda and the stuff you get in health food stores like Herbatint contain nasty phenylenediamine, although at low concentrations.
To get free of chems, stick to vegetable-based semi-permanent dyes - not easy if you're grey. You can always just let it grow naturally, though that's not something I'm thinking about.
What the experts say
"Phenylenediamine [common in dyes] has been shown to cause cancer in animals and is linked by at least one study to breast cancer in humans. There are terrific natural options out there. Henna is really good if your hair has not been treated. Blonds can't use it, but it will work if you're not really, really grey. Health food stores offer other natural colouring agents. If you are going to use regular dye, it's safest to use a rinse that will wash out in a few shampoos or go with a semi-permanent. The biggest threat is from the permanent dyes, and the kind you get in drug stores are stronger than those used in salons."
KIM ERICKSON, author of Drop-Dead Gorgeous: Protecting Yourself From The Hidden Dangers Of Cosmetics, Las Vegas
"Evidence is weak in the literature on the association of hair dyes with an increased risk of lymphoma and bladder cancer. There is conflicting evidence and no recommendation at this time to stop using hair dyes. [Cancer] prevention recommendations focus on [avoiding] tobacco, a major source of environmentally caused cancers, maintaining a healthy diet and exercising."
MARY GOSPODAROWICZ, professor and chair, department of radiation oncology, U of T, regional vice-president, Cancer Care Ontario
"In the 1970s the [U.S.] National Cancer Institute and others concluded that there was no association between dyes and bladder cancer. We revisited this years later. The earlier studies didn't separate different classes of hair dye - permanent, semi-permanent, all of which contain aromatic amines [like PPD]. But dyes don't all contain the same amines. There was a clear increase in incidence of bladder cancer among women who used permanent hair dye. The association was apparent with one particular form of dye. It could be that the earlier bladder cancer studies were conducted before the hair-colouring social trend became so widespread. We looked at genes and found that some people are slower or faster at detoxifying aro-amines. Slow accelerators were at increased risk. Unfortunately, nobody knows their genotype."
MIMI YU, McKnight Presidential Professor, University of Minnesota Cancer Center, Minneapolis
"Manufacturers manage to stay one step ahead of researchers by changing the dyes every so often. They will just shift an atom here or there, and so it's considered a totally new substance and no one can say it causes cancer or is mutagenic. Aveda products are environmentally responsible and are at least 97 per cent derived from plants, though the remaining portion contains the same ingredients as other dyes. At this point it's impossible to get all-natural permanent dyes."
LUKE GARDEN, colourist and salon educator, Hair by Nature, Toronto