Nearly 80 percent of hair products aimed at black women contain chemicals linked to cancer, infertility and obesity, new research suggests.

Up to 78 percent of relaxers, which are used to permanently straighten hair, contain hormone-disrupting chemicals, known as parabens, a US study found.

Past studies suggest parabens, which are used as preservatives, mimic oestrogen and may cause cancer, weight gain and reduced muscle mass.

Up to 78 percent of hair products, including leave-in conditioners, also contain phthalates, the research adds.

Phthalates are added to prolong products' shelf lives and have been linked to breast and ovarian cancer, as well as early menopause.

Out of the 18 products analysed, 11 contain chemicals that are banned under the EU cosmetic regulations due to their links to cancer and female infertility.

Previous research suggests black women are more likely to use straightening and moisturising hair products to try and meet social beauty norms.

Nearly 80 percent of hair products aimed at black women contain cancerous chemicals (stock)

MORE THAN 90% OF RECEIPTS CONTAIN CHEMICALS LINKED TO INFERTILITY, AUTISM AND TYPE 2 DIABETES More than 90 percent of receipts contain chemicals linked to infertility, autism and type 2 diabetes, research suggested in January 2018. The so-called 'gender-bending' chemical Bisphenol A (BPA) and its 'healthier alternative' Bisphenol S (BPS) are added to 93 percent of receipts given out in stores, with just two percent having no chemical coating at all, a study by the Michigan-based non-profit organisation The Ecology Center found. Cashiers and waiting staff, who frequently handle receipts, are particularly vulnerable to the chemicals' effects, the research adds. BPA, which reacts with estrogen and thyroid-hormone receptors, has been linked to infertility, autism, ADHD, obesity, type 2 diabetes, premature births and early onset of puberty. Health fears prompted BPA to be replaced with BPS, however, evidence suggests this disrupts babies' development in the womb. BPA and BPS, which are added to receipts to make their writing darker without using ink, are also often found in plastic water bottles and food containers. The US Food and Drug Administration has banned BPA from baby bottles, while The European Commission prohibits the chemical from being added to receipts from 2020. Past research reveals cashiers and waiting staff can handle as many as 30 receipts an hour. After a shift, such workers have significantly higher BPA and BPS levels in their blood and urine than the average person. Previous studies suggest BPS can be found in the urine of 81 percent of people living in the US, of which 90 percent can be traced to receipts. Past research also reveals even briefly handling receipts causes a significant amount of BPA or BPS to be absorbed into the body, which increases up to 10 times if the person has greasy or moist fingers, or has recently applied hand sanitizer or lotion. Advertisement

'Black women are over-exposed and under-protected'

Results further suggest that hair products aimed at black women contain up to 45 hormone-disrupting chemicals, which are not generally listed on their labels.

All of the products contain at least one fragrance, which have previously been described as 'gender benders' due to them encouraging male-breast growth.

The worst offenders were found in hair lotions, root stimulators and relaxers.

Lotions claim moisturise, while root stimulators are thought to encourage hair growth and strength.

Lead author Dr Jessica Helm, from the Silent Spring Institute, Massachusetts, said: 'Chemicals in hair products, and beauty products in general, are mostly untested and largely unregulated.

Janette Robinson Flint, from the nonprofit organisation Black Women for Wellness, added: 'Black women are over-exposed and under-protected from toxic chemicals.'

'This study is evidence that hair products are an important source of toxic chemicals and that we need to remove these risks to protect black women's lives and prevent harm.'

Use natural, organic products

The researchers hope their findings will lead to clearer ingredient labeling on products.

They also encourage hair-product manufacturers to make safer cosmetics.

In the meantime, the scientists advise people reduce their chemical exposure by looking for products that are paraben and fragrance free.

People should also choose plant-based or organic products, they add.

How the research was carried out

The researchers analysed 18 hair products marketed towards black women.

These products were made up of hot-oil treatments, anti-frizz polishes, leave-in conditioners, root stimulators, hair lotions and relaxers.

The aforementioned products were chosen based on a 2005 survey of 301 women living in New York. The survey's black participants, which made up more than half of the total, used these six products most frequently.

The researchers tested the products for 66 chemicals.

The findings were published in the journal Environmental Research.