Many consumers are concerned about whether an olive oil relaxer can cause cancer. A chemical hair relaxer is a potent product designed to permanently alter the structure of coiled or curly hair for a straight style. The inclusion of ingredients like olive oil does not change the product’s fundamental classification as a strong chemical treatment. This article examines the current scientific understanding of the potential health risks associated with these hair straightening products.
Understanding Chemical Hair Relaxers
Chemical hair relaxers use high-alkaline compounds to penetrate the hair shaft and break the disulfide bonds that determine the hair’s natural curl pattern. The two main types are lye relaxers (using sodium hydroxide) and no-lye relaxers (typically using guanidine hydroxide, lithium hydroxide, or potassium hydroxide). Both formulations are highly alkaline, with a caustic pH ranging from 10 to 14, designed to chemically restructure the hair.
The straightening process is known as lanthionization, performed by the active chemical agent. Products labeled with moisturizing ingredients like olive oil are still fundamentally based on strong alkaline chemicals. These added oils act as conditioning agents to mitigate the drying and damaging effects of the harsh chemicals on the hair and scalp. Olive oil, rich in fatty acids and Vitamin E, helps lock in moisture and protect the hair shaft from becoming brittle.
The Scientific Evidence Linking Relaxers to Cancer
Recent large-scale epidemiological studies have established an association between the frequent use of chemical hair straightening products and an increased risk of certain hormone-sensitive cancers. Researchers suggest that caustic chemicals can cause minor burns or lesions on the scalp. This creates a pathway for concerning ingredients to be absorbed directly into the bloodstream, contributing to the potential health risk through repeated, long-term exposure.
The National Institutes of Health (NIH) Sister Study tracked over 33,000 women. It found that women who reported frequent use of hair straightening products (more than four times in the previous year) were about two-and-a-half times more likely to develop uterine cancer than non-users. This elevated risk was also observed in women who used straighteners for more than five years. The study noted that while the overall risk of uterine cancer is relatively low, frequent use can double that risk by age 70.
Similar research has found associations with other hormone-sensitive cancers. Frequent use of relaxers has been linked to a higher incidence of ovarian cancer, with some studies showing a 50% increased risk for women who used them more than four times annually. For breast cancer, some analyses have suggested an elevated risk, especially for frequent users of lye-based formulas, though results remain inconsistent across studies. This consistent link across hormone-sensitive cancers points to the role of certain chemicals within the relaxers that disrupt the body’s natural hormonal balance.
Identifying the Most Concerning Ingredients
The cancer risk concern is not centered on olive oil, but on specific Endocrine Disrupting Chemicals (EDCs) commonly included in relaxer formulas. EDCs are substances that interfere with the body’s endocrine (hormone) system. They can mimic or block the action of natural hormones like estrogen, and this hormonal interference is thought to fuel the growth of hormone-sensitive cancers (uterus, ovaries, and breasts).
Among the most concerning EDCs found in hair relaxers are phthalates, parabens, and formaldehyde-releasing preservatives. Phthalates, often used to bind and stabilize products or listed vaguely as “fragrance,” can be absorbed through the skin or inhaled as fumes. One specific phthalate, di(2-ethylhexyl) phthalate (DEHP), is regarded by some agencies as a probable human carcinogen.
Parabens (such as methylparaben, propylparaben, and butylparaben) are widely used as preservatives to prevent microbial growth. These compounds are known EDCs that interact with estrogen pathways. Additionally, some relaxers, especially keratin or smoothing treatments, can contain or release formaldehyde, a highly carcinogenic chemical, particularly when heat is applied. These ingredients are the focus of research because their molecular activity directly relates to the type of cancers being observed.
Reducing Exposure and Safer Alternatives
Individuals who continue using chemical relaxers can take several steps to minimize chemical exposure and potential scalp irritation. Reducing the frequency of application is a primary measure, as studies suggest that using the product more than four times a year is associated with the highest risk. Ensuring the scalp is healthy and free of cuts, scrapes, or inflammation before application can also reduce the absorption of chemicals into the bloodstream.
It is important to avoid direct application of the product to the scalp, applying it only to new hair growth. Thorough rinsing with a neutralizing shampoo after the process helps stop the chemical reaction and remove residual product. Reading ingredient lists to avoid known EDCs like phthalates and parabens is another proactive measure consumers can take.
For those looking to avoid chemical straighteners entirely, several non-chemical alternatives are available for achieving a smoother hairstyle.
Non-Chemical Alternatives
- Heat styling using blow dryers or flat irons can temporarily straighten the hair by breaking the hair’s hydrogen bonds, though excessive heat must be managed to prevent damage.
- Professional treatments that use amino acids and proteins, such as cysteine treatments, smooth the hair without the harsh chemicals found in traditional relaxers.
- Physical methods like roller sets, hair wrapping, or using silicone-based creams offer temporary straightening without permanent chemical alteration.