Hair straighteners and uterine cancer
The recently concluded Sister Study found that hair relaxers need to be researched in greater depth, because some of the chemicals in these products may have the potential to cause cancer. (Photo: Pexels)

What's all the fuss about hair relaxers? Recently, public attention was drawn to hair relaxers, because the Food and Drug Administration (FDA) in the United States proposed a ban on those products that contain formaldehyde.

In Jamaica, we commonly use hair relaxers to straighten hair, by chemically changing the bonds that cause the hair to curl. Hair products of concern might contain ingredients that are synonyms for formaldehyde or methylene glycol, such as formalin, methanal, methanediol, or formaldehyde monohydrate. Hair salon products might also contain chemicals that release formaldehyde when the product is heated, such as during flat ironing or blow-drying.

Some examples of chemicals that release formaldehyde include timonacic acid, dimethoxymethane, or decamethyl-cyclopentasiloxane. All of these are big, confusing chemical names that are usually found on the back of the package in the ingredients list. Even with all this information, it can still be difficult to tell which hair products contain or can release formaldehyde. Even products that do not list formaldehyde or methylene glycol on the label, or that claim to be "formaldehyde free" or "no formaldehyde," can still expose workers and clients to formaldehyde.

In addition to formaldehyde, chemical relaxers contain many other substances that are irritants to the skin, eyes and lungs and may cause other health problems with prolonged exposure.

Haircare products are a multi-billion dollar business in Jamaica. An article in the Jamaica Observer in February 2022, highlighted that total imports in 2019 and 2020 were above $676 million, and hair waving or straightening products remained the best-sellers in the haircare market. They reported that according to the Statistical Institute of Jamaica (Statin), the largest market was for hair straighteners and lacquers, with just over $314 million imported from the United States alone in each year.

So why is a gynaecologist concerned with something that goes on the head? In December of 2022, researchers published the results of a study, called the Sister Study. They wanted to see if there was an association between hair-straightening products and uterine (womb) cancer. Previous studies had already noticed an increased risk of breast and ovarian cancer with use of these products and they wanted more information.

They asked women to report their use of hair dyes; straighteners, relaxers, or pressing products; and permanent or body waves in the prior 12 months. They found that using hair straighteners frequently (more than 4 times in 12 months) versus none at all, was associated with higher rates of uterine cancer. The rates of cancer more than doubled, from 1.46 per cent up to 4.45 per cent for those who used it frequently. They concluded that these findings indicate that hair relaxers need to be researched in greater depth, because some of the chemicals in these products may have the potential to cause cancer. It's also possible that some of the chemicals in hair straighteners are endocrine disruptors, and may interfere with hormone production in some way.

In Jamaica, cancer of the lining of the womb (endometrial cancer) is the second commonest gynaecologic cancer (following cervical cancer), with the highest incidence occurring in the 60 to 65 years age group. In my local clinic, endometrial cancer is the second most common diagnosis for new patients joining the clinic for the first time, and patients with endometrial cancer make up the greatest percentage of follow-up patients. The number of patients presenting with womb cancer has also been climbing slowly over the years worldwide and in Jamaica, and is thought to be due to increased rates of obesity, sedentary lifestyles and prolonged life spans. Of concern also, is the fact that survival rates have not been improving over the past 30 years, unlike other cancers, despite improvements in diagnostic and treatment capabilities.

Several risk factors for endometrial cancer have been identified, with most being linked to excessive oestrogen stimulation, or genetic mutations causing a predisposition to atypical endometrial changes.

The risk factors include: Obesity, older age, not ever being pregnant (especially if due to infertility related to certain hormonal imbalances), starting periods very early and going into menopause late, using high doses of tamoxifen, diabetes, and a strong family history. Now we have potentially identified another risk factor, especially in black women.

From the FDA's website, I found the following useful questions you can ask your salon or haircare provider:

1. Does the product contain formaldehyde?

2. Is there an ingredient list available for this product that I could read?

3. Would it be possible for me to review the Safety Data Sheet for this product?

4. Have you been trained to apply this product, and do you know the necessary safeguards to minimise exposure to formaldehyde?

5. May I see your training certificate from the manufacturer and the directions for product use?

6. Does the salon have proper ventilation?

7. Do you periodically test the air for adherence to the Occupational Safety and Health Administration's limits for formaldehyde?

8. Do you have an alternative hair smoothing product that does not release formaldehyde when heated?"

As an oncologist who deals with women's cancers daily, it is my duty not just to treat cancer, but to help provide information on and strategies for prevention of gynaecologic cancers.

It's important to note that in science, association doesn't mean causation, so this study does not explain the relationship noted. But it does tell us that we need to pause and do more research to figure out the exact links and possible causative agents with respect to hair relaxers.

Anything that we can do to identify risk factors and decrease the number of women diagnosed with uterine cancer is helpful. Hopefully women will take this information, look at their lifestyle and risk factors and consider individually whether or not they really need to use these products.

I encourage schools, employers and society as a whole to accept women's hair in its natural state, without pressuring them to conform to standards that require them to use harmful chemicals to achieve the goal.

Dr Anna-Kay Taylor Christmas is a consultant obstetrician and gynaecologist, gynaecologic oncologist and laparoscopic surgeon. She is located at Suite #15, Winchester Business Centre. Contact: 876-908-3263, 876-906-2265

Dr Anna-Kay Taylor Christmas.

Now you can read the Jamaica Observer ePaper anytime, anywhere. The Jamaica Observer ePaper is available to you at home or at work, and is the same edition as the printed copy available at


  1. We welcome reader comments on the top stories of the day. Some comments may be republished on the website or in the newspaper; email addresses will not be published.
  2. Please understand that comments are moderated and it is not always possible to publish all that have been submitted. We will, however, try to publish comments that are representative of all received.
  3. We ask that comments are civil and free of libellous or hateful material. Also please stick to the topic under discussion.
  4. Please do not write in block capitals since this makes your comment hard to read.
  5. Please don't use the comments to advertise. However, our advertising department can be more than accommodating if emailed:
  6. If readers wish to report offensive comments, suggest a correction or share a story then please email:
  7. Lastly, read our Terms and Conditions and Privacy Policy

Which long-term investment option is more attractive to you at the moment?