Author: Andrei Bilog M.Sc., CAPM
Chemical hair straighteners and relaxers have been used for decades to achieve smooth, sleek hair—but new NIH-supported research suggests these products may carry more health risks than many people realize. A recent article discussing the study breaks down how certain chemicals in these products could be linked to higher cancer rates in women.
Let’s simplify the science so it’s easy to understand.👇
💡 What Did the Researchers Study?
The findings come from the Sister Study, a large research project following 46,000+ women for over a decade. At the beginning of the study, women shared whether they used hair-straightening or relaxing products.
Researchers then tracked health outcomes for about 13 years.
🧪 The Key Findings — Explained Simply
1️⃣ Higher Risk of Certain Cancers
Women who used chemical straighteners or relaxers had:
2× higher risk of pancreatic cancer
70% higher risk of thyroid cancer
60% higher risk of non-Hodgkin’s lymphoma
➡️ What this means: It doesn’t guarantee these products cause cancer, but the association is strong enough that scientists are concerned.
2️⃣ Why Might These Products Increase Risk?
Some hair-straightening or relaxing products contain chemicals that may be harmful when absorbed through the scalp:
Formaldehyde & formaldehyde-releasers — known carcinogens
Parabens & phthalates — can disrupt hormones
Bisphenol A (BPA) — linked to inflammation & endocrine effects
Metals & other harsh ingredients
Because these treatments often involve scalp irritation or burns, the chemicals may enter the body more easily.
3️⃣ This Affects Some People More Than Others
Black women are statistically the heaviest users of straighteners and relaxers.
However, the study didn’t have enough cases to make strong race-specific conclusions.
Still—this highlights a major public health and equity issue.
✨ What You Can Do — Practical, Health-Conscious Upkeeping Tips
✔️ 1. Reduce Frequency When Possible
Even cutting down use from several times a year to rarely can lower exposure.
✔️ 2. Be Cautious with Irritated Scalps
Never apply relaxers or straighteners on:
burns
cuts
inflammation
scabs
Damaged skin absorbs more chemicals.
✔️ 3. Read the Ingredients
Look for products marketed as:
formaldehyde-free
paraben-free
“clean” or low-chemical formulations
(Not perfect—but safer.)
✔️ 4. Consider Alternative Styling
Heat-free stretching
Silk pressing (occasional)
Protective styles (braids, twists, buns)
Embracing natural texture
Your hair AND your long-term health can benefit.
✔️ 5. Ventilate the Space
If using chemical treatments at home or in a salon, open windows or use a fan.
🧠 Big Picture: Should You Panic?
No.
BUT… you should stay informed.
This study shows a possible link, not definitive proof. Still, the risks were strong enough for scientists to call for caution, especially given how long these products have been used and how early some people are exposed.
🔍 Reference
Lindquist, K., et al. “Hair-straightening/relaxing product use and incidence of multiple cancer types in the Sister Study cohort.” Journal of the National Cancer Institute (advance online publication). https://doi.org/10.1093/jnci/djaf280
More about Andrei Bilog
A dedicated professional and educator, serving as the Founder and Editor-in-Chief of UPkeeping Newsletter. His expertise stems from a powerful combination of experience: 7+ years in the biotech industry, a current MBA pursuit at the University of Illinois Urbana-Champaign, and his role as an adjunct professor of Human Anatomy & Physiology. As the President of the Beta Psi Omega National Chapter, Andrei is passionate about student mentorship and guiding the next generation of lifelong learners toward strong career and wellness foundations.
