TL;DR:
Medically reviewed by Kandace Licciardi, MD, Medical Director, Amen Clinics
Could your hair color routine be silently affecting your memory?
Have you noticed increasing forgetfulness, mental fog, or subtle cognitive changes, but can’t pinpoint why? The cause may be closer than you think.
Toxins find their way into everyday life, often in places we rarely question. Some chemicals may be hiding in hair dye, with the potential to affect brain health, cognition, and even mood over time.
While research on hair dye and memory loss is still emerging, the evidence raises important questions worth paying attention to.
In this blog, we’ll explore what science currently says about hair dye chemicals, cognitive decline, and other possible health effects. You’ll also learn practical ways to reduce your exposure and protect your brain.
Toxic ingredients can lead to unexpected effects on the brain. And you may not even realize that your symptoms are related to your hair color routine.
The skin on your scalp is highly absorbent, potentially up to four times more than other skin areas, allowing toxins from hair products or the environment to enter the bloodstream via hair follicles.
Researchers have questioned the interaction between hair coloring and brain health. Hair colorants can contain troublesome chemicals such as paraphenylenediamine, ammonia, heavy metals, and endocrine disruptors. These chemicals have been associated with mental and brain health issues.
According to the nonprofit initiative Campaign for Safe Cosmetics, the following hair dye ingredients have been linked to health issues:
Resorcinol: In permanent hair dyes, resorcinol reacts with a developer (such as peroxide) to bond a dye permanently to hair strands. Evidence from case studies, animal studies, and in vitro studies has linked resorcinol to disrupted thyroid function.
Resorcinol is also listed on labels as 1,3-benzenediol, resorcin, 1,3-dihydroxybenzene (m-hydroxybenze, m-dihydroxyphenol).
Paraphenylenediamine (PPD): This ingredient in permanent hair dyes is part of a class of chemicals called aromatic amines, which are suspected to be carcinogenic. When P-phenylenediamine reacts with hydrogen peroxide, as it does in hair colorants, it can expose users to a mutagenic, or DNA-altering, substance.
P-phenylenediamine is also listed on labels as para-phenylenediamine, 4-aminoaniline; 1,4-benzenediamine; p-diaminobenzene;1,4-diaminobenzene; 1,4-phenylene diamine.
Toluene: This substance, found in hair dye as well as nail polish, is dangerous at high levels of exposure, potentially affecting salon employees. High levels of inhalation can contribute to central nervous system dysfunction.
Even low to moderate daily exposure to toluene has been associated with tiredness, confusion, weakness, nausea, and memory loss. Exposed workers have experienced hearing and color vision damage, reduced ability in cognitive and neuromuscular function tests, and neurotoxic symptoms.
Meanwhile, lower exposure levels have been associated with neurobehavioral changes, such as compromised attention, concentration, and motor performance.
It appears very likely that chemical exposure can influence brain function. Research has shown that neurotoxins can induce neurotoxicity through oxidative stress. This process contributes to neurodegenerative diseases, such as Parkinson’s disease, Alzheimer’s disease, and Huntington’s disease.
Amen Clinics has observed this issue firsthand with clients. For example, one man visited Amen Clinics because he was experiencing memory issues. When an integrative/functional medicine physician on staff completed a comprehensive evaluation to determine the root cause, results were surprising.
The physician, who had more than 20 years of experience in testing for toxic metals, decided to test this patient’s hair lead levels. Normal results would show less than 0.8 micrograms per deciliter, but this patient’s level was dangerously high at 710 micrograms per deciliter. That’s about 900 times higher than normal!
The physician had never seen such a high level of lead in a patient. He was also surprised to see elevated levels of thallium and cadmium, heavy metals that can also contribute to health problems.
If you’ve ever wanted to cover gray hair as you age or try a new look with hair dye, be aware that toxic ingredients can lead to unexpected effects on the brain. And you may not even realize that your symptoms are related to your hair-color routine.
In 2022, lead acetate was banned from hair dyes by the U.S. Food and Drug Administration (FDA). This FDA’s determined that the available information on lead acetate no longer demonstrated a “reasonable certainty of no harm” – the safety standard for a color additive used in cosmetics. This was a major win for American health, as well as salon workers, since lead is a toxin that harms the brain.
Lead exposure is associated with:
Mental health issues include the possibility of adult-onset schizophrenia, as well as increased risk of depression and panic disorder. One study found that even so-called “safe” levels of lead exposure can result in adverse mental health outcomes.
It’s a relief that lead has been removed from hair dyes and other cosmetics sold in the U.S. But estimates state that 75 percent of American women and almost 40 percent of men use hair dye. Individuals who have been coloring their hair for years or decades have been exposed to previous formulations.
Over decades of serving clients at its clinics nationwide, Amen Clinics has amassed the world’s largest database of SPECT brain scans. This work has made evident a clear association between environmental toxins, brain health, and psychiatric and cognitive problems.
In modern life, it’s impossible to avoid toxins altogether. They exist in a variety of substances that people are commonly exposed to, such as house paint, gasoline, cleaning products, and mold.
Related: Toxic Brain Quiz: 23 Everyday Toxins That Destroy Thinking
Unfortunately, toxin exposure has been associated with a variety of physical and psychiatric symptoms. Physical changes can include:
In terms of psychiatric changes, exposure to toxins can increase the risk of:
Moreover, if you already struggle with mental health disorders, memory impairment, or other cognitive issues, additional exposure to toxins may further worsen your symptoms.
Exposure to toxins can lead to a phenomenon that Amen Clinics physicians call a toxic brain. This is characterized by a scalloping pattern and overall decreased blood flow on brain SPECT imaging. Scans indicate that repeated exposure to toxins can harm your brain over time.
Related: 9 Ways to Prevent Toxins From Stealing Your Mind
But the whole body is affected by toxin exposure. In addition to the brain, toxins can disrupt the endocrine and immune systems; the gut’s microbiome; and organs like the digestive tract, liver, and kidneys.
Various studies have examined the carcinogenic properties of hair dye. Carcinogenic substances like metals can enter the brain and accumulate, even destroying the blood brain barrier, according to a study from 2020.
In the brain, their presence and accumulation were found to activate pathways that alter the brain’s neurochemistry that is designed to support cognitive and motor function.
Carcinogens, by definition, are also linked to cancer. According to a study published in 2022, a positive association between hair dye use and cancer occurrence has been noted in specific subpopulations.
These researchers called for more investigation on the mechanisms behind the toxicity of both hair dye mixtures and individual hair dye ingredients. They recommended further in-depth chemical and systems toxicology studies to fully understand the issue.
Another study, which tracked 7,684 women long term (37 years), found that participants who used hair dye were about twice as likely to develop malignant melanoma (a dangerous type of skin cancer), compared to women who did not use hair dye. Hair color users also had a slightly higher rate of digestive problems and a higher risk of Parkinson’s disease.
No higher risk was found for other types of cancer or other diseases, and it did not appear to increase the risk of dying from any cause. But a follow-up analysis reinforced the higher risk of malignant melanoma, with hair dye users showing an even stronger increased risk than originally observed.
In light of the above research and other studies, a review published in 2023 noted that hair dyes and perming products have been shown to contain known carcinogens, linked to breast, bladder, blood, ovarian, and prostate cancers.
The authors also warned that certain hair dyes have been found to contain small amounts of heavy metals, which may increase cancer risk over time. But, they added, health effects from hair dye use may vary among different populations.
Authors referred to numerous risk factors and exposure variables found in previous studies:
However, this review concluded, the evidence linking hair dye and cancer is not always consistent. More research is needed to clearly understand who is most at risk and why.
While hair dye users have reported cognitive symptoms and memory issues, and studies have established links between hair dye and health concerns, there are limitations to these findings.
Some studies have not fully explored whether hair dye causes health issues or is merely correlated with them. Additional factors possibly playing a role include exposure to other toxins, such as through environmental pollutants and lifestyle choices. Other studies have had limited sample sizes.
Still, while awaiting further research, the good news is that you can take steps to lower your risk of negative health effects when using hair color products. Here are some steps to take for neuroprotection:
Though more evidence is needed on hair dye and memory loss, findings suggest that hair dye users should exercise caution and awareness.
Unfortunately, in our modern-day environment, everyone is exposed to toxins. And, while toxin exposure has been linked to many kinds of mental illnesses and physical ailments, everyone can also minimize their risk.
By being mindful of your lifestyle, environment, and routines, you can help reduce exposure to brain and mental health toxins. Limiting or eliminating potentially dangerous personal care products is an easy step you can take to start.
Engage in mindful product choices and protective practices, and choose safer haircare options to minimize risk. Consult with a brain health expert and receive cognitive screening to diagnose and treat any symptoms that arise, before they evolve into more serious cognitive health issues.
While more research is needed to explore the connections between hair dye and memory loss, we know that toxin exposure can affect brain health. SPECT scans at Amen Clinics have shown that toxic brains are characterized by a scalloping pattern and overall decreased blood flow. These changes can impact mental health, cognition, memory, and more.
Studies are inconclusive on all of the mechanisms and variables behind hair dye and brain health. However, lowering exposures (for example, by dyeing hair less frequently) and using safer formulas will help reduce potential effects.
Generally, semi-permanent dyes (which do not penetrate the hair shaft) and natural/organic/vegetable dyes are considered safer alternatives to harsher formulas with ammonia. However, keep in mind that these types can also harbor dangers like heavy metals, pesticides, and more. Choose reputable companies with transparent ingredient lists and sourcing.
Memory loss, brain fog, mental health symptoms, or behavioral changes should be taken seriously. At Amen Clinics, SPECT scans can help determine if and how the brain has been affected by toxins, enabling a targeted, personalized treatment plan to assist in brain health and recovery.
Memory loss, brain fog, and other mental health conditions can’t wait. At Amen Clinics, we practice precision medicine — using brain SPECT imaging and comprehensive evaluations to understand what’s really happening in your brain, not just your symptoms.
Our whole-body approach to holistic psychiatry combines cutting-edge neuroscience with natural ways to treat mental health conditions, including targeted nutrition, supplements, lifestyle strategies, therapy, and medications (when necessary). Every treatment plan is personalized to address the root causes of your struggles and support the health of your brain, body, and mind.
Don’t settle for guesswork. You deserve answers—and a plan built specifically for you. Speak with a Brain Health Advisor today at 888-288-9834 or visit our contact page to get started.
About the Reviewer
Kandace Licciardi, MD, Medical Director, Amen Clinics
Dr. Kandace Licciardi is a double board-certified psychiatrist in adult and forensic psychiatry and serves as Medical Director of Amen Clinics Dallas Metro Area. She takes a comprehensive, whole-person approach to care, integrating evidence-based psychiatric treatment with lifestyle, social, and wellness factors. Dr. Licciardi has extensive experience treating depression, anxiety, bipolar disorder, psychotic disorders, and borderline personality disorder, with special expertise in early psychosis intervention. She completed her psychiatry residency at Maimonides Medical Center and her forensic psychiatry fellowship at New York University.
Campaign for Safe Cosmetics:
https://www.safecosmetics.org/chemicals/resorcinol/
https://www.safecosmetics.org/chemicals/p-phenylenediamine/
https://www.safecosmetics.org/chemicals/toluene/
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He Yongyu, Cao Yu, Nie Binji, Wang Junpu. Mechanisms of impairment in hair and scalp induced by hair dyeing and perming and potential interventions. Frontiers in Medicine, Volume 10 – 2023. https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2023.1139607. DOI 10.3389/fmed.2023.1139607. ISSN 2296-858X.
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