Researchers have discovered that chemical hair relaxers or straighteners are associated with an increase in the risk of uterine cancer.
Senior epidemiologist and Black Women's Health investigator Dr Yvette Cozier has been studying the links between cancer and chemical hair relaxers since 1995.
Her team at Boston University created the largest study of its kind, gathering data from nearly 60,000 black women.
“A chemical hair relaxer contains caustic agents like lye. So think of what cleans your drain.
“It gets applied to the root and the shaft of the hair and causes the bonds of the hair, which is normally very curly, to break for it to straighten.
"And this is a temporary thing. So using it once is one thing but often it's used in repeated fashion maybe every two to three months to maintain that straighter texture of hair.
“It's marketed primarily to African-American or women of African descent.”
ITV’s current affairs series Wales This Week surveyed 100 people of colour in Wales.
85% said they have used chemical hair relaxers and 59% said they experienced negative side effects from them - including burns, sores and bald patches.
Dr Cozier explained: “Sodium hydroxide is the basis for lye. And it's very caustic… If it stays on the skin too long, it can burn the skin and you can get pretty severe burns, not just the first degree but you can get second and third degree burns... It's a pretty hard price to pay for one's hair.”
In recent years, there have been reports of more than 7,000 lawsuits worldwide trying to tackle the issue of chemicals in hair relaxers.
Some relaxers on sale are now marketed as containing “no lye” but Dr Cozier said this does not necessarily resolve the problem.
“We do see more products that don't contain sodium hydroxide or don't contain lye… It might have created another opportunity to put in yet another chemical that replaces it.
“So assuming that the replacement chemical is less caustic than lye, the question still remains - what is in the mix of the fragrances that are added?
“Replacing one chemical does not mean that we've taken the problem away.”
For some, the negative side effects like burns are not enough to put them off using chemical relaxers.
Author Natalie Jones from St Clears said the product has also been known as “creamy crack”. She relaxed her hair for “the best part of 40 years”.
Natalie said: “When I was in primary school, the comments kids would make about my hair were always… even if they weren't trying to be nasty, it was never complimentary.
“And so it always made me feel awkward that it was not pretty hair, that I looked really strange to everybody else - that was stuck in my head. That was the main motivation, really, for relaxing my hair.
“An alarm bell that should have had me ditching the relaxers a long time ago was when I tried to do it when it was the time of the month.
“It would burn like my head was on fire. It would literally make me want to cry and I had to wash it off immediately.
“It kind of seemed worth the risk to have burns, you know another time I did have burns on my forehead where relaxer had got on there and I hadn't realised.”
Natalie said part of her motivation to use hair relaxer was wanting to fit in.
“Wanting to fit in will always be there, even though I want to say yes, I've embraced my natural hair. I do wear my hair in an Afro occasionally but I know that when I step out with my hair in a gloriously big round afro, people are looking and I'm wondering, are they thinking I look untidy?
“Your hairstyle can make you so misunderstood. So for most of my life I felt like if I could get my hair as much like a white persons’ as possible, it cuts out some of those misunderstandings.”
Nearly 70% of people of colour we surveyed said they felt discriminated against because of their natural hair.
Natalie decided to stop relaxing her hair when she developed breast cancer.
“After having breast cancer, my husband said to me that he’d found a study that showed that there may be a link between breast cancer in black women and hair relaxers. And he begged me. He said, ‘Please, please don't ever put that on your head again.’”
She has since recovered from cancer and has stayed away from the chemical relaxers.
Dr Cozier said her study has produced “mixed results when it comes to breast cancer”.
“We see increased associations, maybe a 20, 30% increased risk, but these are not statistically significant. It doesn't mean that there's no increased risk. And what that means for an individual woman is really the risk that she's willing to take.”
But the link with uterine cancer is stronger.
“Women aren't going in there thinking that they are being exposed to terribly toxic mixes… They know the risk of the burns, but they're not thinking of other risks that might be associated with it.
“So having seen our association with over 50% increased risk shows that there's a troubling association between developing uterine cancer, a very rare condition, and frequent use of hair relaxers.”
In Newport, a charity organised an event to celebrate Afro hair and fight back against discrimination.
Nkechi Allen Dawson and Billy Mazoya from the charity Cynefin Pajoma organised Wales’ first televised Afro Hair Show in January 2025.
Nkechi said that Afro hair has been “a way to express our creativity” and “forms a huge part of our identity.”
Billy said: “There's a lot of discrimination towards Afro textured hair. There's lots of stigmas, taboos and challenges, particularly around professionalism and appearance.”
Nkechi added: “I've had comments like your hair looks pretty dry. It looks really brittle. It looks really wiry.
"And that can be quite offensive because I was brought up with relaxers, unfortunately. And for the last ten years, I've stopped relaxing my hair because I want to be more natural.
"When people are making comments like, your hair is wiry or your hair's woolly, it puts me back into that kind of notion of feeling quite self-conscious…
“We found that a lot of children were actually so distraught with their hair that a lot of them actually said that they wanted to be white.”
At the Afro hair show, the owner of Wales’ Afro Hair Academy, Joy Djadi, spoke about how relaxers can be used safely.
“As a professional hairdresser and teacher, I’ve used hair relaxers for many years. The technique that I use, it's such a professional technique that the clients don't get burned.”
But she acknowledges there are risks to using the products.
“For a normal person with no hairdressing skills to go in and just pick up a relaxer off the shelf and be able to buy and go home, they don't know what damage they're doing.”
Joy said she believes the reason people use hair relaxers is a combination of societal pressures and manageability.
“Sometimes you can go into a job and your hair might not be suitable even though you've got the great qualifications and you can do the job.
“But the fact is, you don't look a certain way that can hinder a certain person getting that job.
“Manageability is another factor as well. You can style your hair more when it comes to using a relaxer.”
Joy added: “There’s a huge movement now where everybody is really embracing their curls.
“Textured hair is beautiful.”
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