Lawsuit Against L’Oreal: Do Chemical Hair Straighteners Cause Cancer?

Published on November 15, 2022, by Matthew Sharp

Product Liability

Lawsuit Against L’Oreal: Do Chemical Hair Straighteners Cause Cancer?

People who frequently use chemical hair straightening products and have developed cancer may want to know if chemical hair straighteners cause cancer. Various medical studies show that some hair straighteners have chemicals that expose women to higher risks of developing uterine cancer. Although a recent lawsuit against L’Oreal had put the company’s products in the spotlight, products manufactured by other cosmetic companies may raise users’ risk of developing cancer as well.

A recent study conducted by the National Institutes of Health (NIH) found that women who regularly used chemical straighteners had more than two times greater risk of developing uterine cancer than those who never used the products. 

Available evidence suggests L’Oréal knew that its hair straightening products had harmful chemicals by 2015. The company did not take any reasonable steps to warn users of the dangerous effects of its products.

Consequently, one of the affected users has filed a lawsuit against L’Oréal on the grounds of duty to warn violation. The plaintiff claims that the company actively and deliberately hid essential information to encourage users to continue buying and using its potentially harmful products. 

Do Chemical Hair Straighteners Cause Cancer?

The findings of a recent NIH study show that women who regularly use chemical hair straighteners are likelier to develop cancer than those who do not use the products. The study data comes from over 33,000 American women aged between 35 and 74 years enrolled in the Sister Study. The Sister Study is an ongoing study investigation into the risk factors for various health problems, including breast cancer. 

The women were polled on how frequently they used various hair products in the past year at the start of the study. These products include hair straightening products, relaxers, highlights, dyes, and perms. 

Researchers tracked the women for more than a decade. They found women who frequently used chemical hair straighteners had a 4.05% risk of developing uterine cancer by age 70. The risk for those who never used these chemical hair products was only 1.6%. 

This study indicates that women who regularly used chemical hair straighteners had a twofold risk of uterine cancer. Researchers believe these findings coincide with previous studies that have identified chemical straighteners as a risk factor for other hormone-related cancers, including breast and ovarian cancers, among women. 

If you are a frequent hair dye user and have been diagnosed with cancer, you might ask, “does hair dye cause cancer of the uterus?” The new NIH study did not find any direct associations between elevated uterine cancer risks and frequent use of other hair care products like hair dyes, highlights, and perms.

Data analysis by race revealed that regular hair straightener users of all races had an equal risk of uterine cancer. However, up to 60% of women who had admitted to using hair straighteners in the past year were Black. 

Dr. Che-Jung Chang, one of the study’s researchers, said that the findings might be more applicable to Black women, as they use hair straighteners or relaxers more often than other races. Chang added that Black women start using these hair products at younger ages compared to other races. 

Proving a Product Liability Claim

Manufacturers and companies have a legal duty to make products that guarantee safety. Many companies, however, take shortcuts to save money and make products that expose consumers to serious health risks. 

Some companies may even knowingly sell defective products to unsuspecting consumers. A lawsuit against L’Oréal, for instance, claims the company continued to market its products as the safest hair straighteners despite knowing that they contained potentially hazardous chemicals.  

You might have a product liability claim if you suffered an injury or developed an illness like cancer because of an unsafe or defective product. You must demonstrate the following elements to prove your claim and recover damages: 


You must demonstrate that you sustained an injury or damage after using a product. For instance, let’s say you have been using L’Oréal’s chemical hair straighteners over the years. You recently got diagnosed with uterine cancer. You then learn from a new study that a strong link exists between uterine cancer and these chemical hair straighteners. In this scenario, you might have a valid claim against the company. 

Your claim will be unsuccessful if you did not develop any illness or injury from using these hair care products. This consideration applies even if available evidence shows the chemical hair straighteners are defective. 


You must demonstrate that your injury or harm resulted from a defective product. Note that even a product in perfect condition can harm you if you fail to handle it properly. So, you need to prove that the product harmed you because it was defective. A defect could arise from a design error or manufacturing mistake. It could also stem from a failure to inform consumers of a possible danger. 

You can demonstrate that a product has a design defect if you show that the product carries a risk that an ordinary consumer would not detect. In such a case, liability will boil down to whether the manufacturer provided reasonably enough safety instructions or warnings. 


You must prove that the product’s defect was the direct cause of your injuries or damages. To this end, you might present evidence that links the product’s defect to your injury. 

Product Used as Intended 

You must show that you suffered an injury or damage despite using the product as originally intended. The reason is that the manufacturer must be capable of anticipating that the product could have injured you. You might not have a valid claim if you used the product improperly, modified its original design, or failed to follow safe usage instructions. 

Evidence for Proving a Product Liability Claim 

The burden of proof rests on the plaintiff in product liability cases, like all personal injury cases. So, you must gather and compile the required evidence to prove each element of your claim. Your product liability lawyer will help you navigate the evidence-collection process. The following are pieces of evidence you need to prove your claim: 

The Defective Product Itself 

The defective product is an essential piece of evidence in your case. Presenting it before the judge or jury can help support your claim that the product was defective. It is also a proof that you did not modify the product after buying it. 

Presenting the product before the court can help demonstrate that it lacked adequate safety labels and instructions. So, be sure to keep the defective product in its current state. Avoid repairing or discarding it. 

Pictures and Videos 

Take clear pictures of the injury sustained and the defective product. Enable the time stamp feature of your smartphone to get the correct date and time of the incident. Manufacturers usually upload product demo videos on their YouTube channels and official social media pages.

Your lawyer can review these videos to try to pinpoint defects in the product. The lawyer can also gain insights for bolstering your claim from the videos. 

Medical Records 

Medical records can show the nature and severity of your injuries. Emergency room (ER) records, lab reports, doctor’s notes regarding the injury, admission reports, and discharge summaries are some medical records to obtain and preserve. 

Medical Bills and Receipts of other Expenses Incurred  

Medical bills will be necessary to prove the medical expenses incurred to treat your injuries. Receipts of other defective-product-related payments will also help you maximize your compensation. 

Medical Opinion and Financial Documentation 

You may be entitled to compensation for lost wages or income if you miss work because of your injury. First, you need to prove that you cannot truly work or perform your pre-injury work duties. You can do that by presenting a letter from your doctor describing how your injury impacts your ability to work. 

Past financial documents will help prove your lost wages or income. These documents include wage statements, income tax returns, and bank statements. You might be eligible to recover compensation for your future lost earning potential if your injury will prevent you from working permanently.

Your lawyer will analyze various factors, including your age, type of job, expected future raises, and lost benefits when calculating your future lost wages. The lawyer will then use job-related financial documents and expert witness testimony to prove future lost wages and reduced earning capacity. 

What Dangerous Chemicals are in Hair Straightener Products?

Some hair straightening products have chemicals that disrupt the endocrine system’s functioning. They trigger the overproduction of female reproductive hormones estrogen and progesterone. As such, these chemicals are called endocrine disruptors. 

Medical research suggests that exposure to too much estrogen and imbalances in the female reproductive hormones increase the risk of uterine cancer. Up to 95% of uterine cancer begins in the endometrium, the uterine lining. Estrogen is the hormone responsible for stimulating the endometrium. Any factor that triggers the overproduction of estrogen can elevate the risk of endometrial cancer. 

Phthalates or phthalate esters are some examples of endocrine disruptors found in hair straightening products. L’Oréal and other manufacturers use these chemicals to give their products a “softer” feel. 

Hair straightening products also contain other potentially dangerous chemicals. Relaxers are believed to have strong sodium hydroxide to separate disulfide bonds in kinky hair. Keratin smoothing treatments are thought to consist of carcinogenic formaldehyde or chemicals that convert into formaldehyde when exposed to heat. Formaldehyde tends to vaporize from the hair care product. It can then enter your body through the eyes or nose. 

Hair straighteners are usually smeared on the base of the hair. They are likely to find their way into the scalp. You might develop burns on the scalp if you frequently use these products. Potentially hazardous chemicals can enter your body through the openings created by the burns.

The Federal Food, Drug, and Cosmetic Act (FD&C Act) do not require hair product manufacturers to seek FDA approval before releasing their products to the market. Manufacturers and companies, however, have a legal duty to use safe ingredients and ensure their products are reasonably safe. You might have grounds for a toxic tort lawsuit if you suffered harm after using a hair straightening product as instructed. 

Was L’Oréal Aware that its Hair Straighteners Had Potentially Harmful Chemicals?

Available evidence indicates that L’Oréal knew its hair straighteners had potentially dangerous chemicals by 2015. The FD&C Act did not require the company to get prior authorization before introducing the products into the market. 

The Act does not require manufacturers and companies that produce hair care products to provide a list of each specific chemical used in their products. Instead, they classify them into “perfume” or “fragrance” ingredients. 

The outcome is that consumers who bought L’Oréal hair straighteners did not know that the product had a potentially cancer-causing chemical. The company, however, was aware that its products had a harmful chemical that could harm consumers, even if they used the products as instructed. So, failure to warn forms the grounds for a recent lawsuit brought against the company. 

How to Minimize Your Risk 

You need to strike a healthy balance between achieving straighter hair and your risks of cancer and other health conditions associated with chemical hair straightening products. You can do that by implementing any of the following tips: 

Reduce the Frequency of Using Chemical Straighteners 

As previously mentioned, the NIH study found that frequent users of chemical straighteners had a higher risk of uterine cancer than their counterparts who used the products less frequently. Reducing how often you straighten your hair can help minimize your health risks. It can also strengthen your hair and protect your scalp from burns. 

Choose the Best Hair Straightener 

Multiple studies on the safety of hair care products are available online. So, be sure to do your due diligence and choose products that have been determined to be reasonably safe. 

Look for a Professional Saloon with Competent Stylists 

Getting chemical treatment from a professional salon with highly trained stylists reduces the risk of these products coming into direct contact with the scalp and causing scalp burns. Find a salon with sufficient ventilation if your treatment involves chemicals that release potentially harmful fumes. Ask your stylist about the ingredients of the straighteners the stylist is using. 

Avoid Chemical Straighteners Completely 

The safest remedy against the health risks of chemical straighteners is to avoid these products altogether. Another option is to use heat-based styling tools like flat irons, blow-dry brushes, and straightening brushes. You can also use products that temporarily straighten your hair, such as hair serums, shampoos, and conditioners, if worried concerned that hair straighteners cause cancer.