What a Strand of Hair Can Reveal About Your Child

Parents monitor countless details in their children’s lives, from sleep and nutrition to school progress and screen time. Yet many of us know surprisingly little about the environmental factors surrounding our families every day. Dr. Manish Arora wants to change that.

An environmental epidemiologist and exposure biologist, Dr. Arora is the Edith J. Baerwald Professor and Vice Chairman of the Department of Environmental Medicine at the Icahn School of Medicine at Mount Sinai. He is also the founder and CEO of LinusBio and, as he proudly shared during our Trust Me Mom conversation, the father of teenage triplet daughters. In the interview, he told me, “My biggest achievement is that I’m a dad.”
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His work explores the exposome, which the National Institutes of Health describes as the full set of environmental exposures a person encounters throughout life, along with the body’s biological responses. While our genes remain largely fixed, our exposures change constantly through the air we breathe, the water we drink, the food we eat, the products we use, and the places where we live.

For Dr. Arora, one question has guided decades of research: Can the body preserve a record of those changing exposures, and can scientists learn to read it?

A Childhood Shaped by Environmental Questions

Dr. Arora’s interest in environmental health began long before he entered a laboratory. He spent part of his childhood in a remote region of Africa during a civil war and a malaria epidemic. He remembers trucks driving through communities and spraying DDT while conflict unfolded around him.

His father, a chemical engineer, taught him that chemicals could move through soil, water, and air. Those early lessons helped him see that human activity can alter the environment and, in turn, affect health.

Dr. Arora initially trained in dentistry and oral surgery. Later, while studying public health in Australia, he encountered research by scientists Herbert Needleman and David Bellinger, whose work helped establish the serious effects of childhood lead exposure. Their use of baby teeth to study exposure history immediately captured his attention.

He was a dentist fascinated by environmental health. Suddenly, the two paths belonged together.

Why the Timing of an Exposure Matters

Environmental health research presents a difficult problem. Measuring how much of a substance is present is only part of the story. Scientists must also ask when the exposure occurred.

“It’s not just how much you’re exposed to,” Dr. Arora explained. “It’s when you’re exposed.”

An exposure during fetal development or infancy may affect the body differently than the same exposure later in life. Individual susceptibility also varies. Age, health, genetics, nutrition, and the timing of exposure can all influence how a person responds.

That makes reconstructing the past especially challenging. If a health concern appears when a child is 10, researchers may need to understand exposures that occurred years earlier, perhaps even before birth.
Dr. Arora began searching for what he calls a biological time machine.​

The Tree-Ring Moment That Changed His Research

The breakthrough came while Dr. Arora was looking at the growth rings inside a tree. One ring appeared thinner and more distorted than the others, suggesting that the tree had experienced drought or another stress during that year. “This was just nature showing me the way,” he recalled. 

He wondered whether the human body contained a similar chronological record. Baby teeth, he realized, begin forming during pregnancy and develop in layers. Those layers can preserve information about nutrients, chemicals, and biological stress over time. Dr. Arora compares them to the grooves of a vinyl record. Instead of storing music, they hold a sequence of biological information.

Testing that idea required technology far beyond traditional dentistry. As a PhD student in Australia, he connected with physicist Chris Ryan, who gave him access to specialized equipment attached to a nuclear reactor. Because the machine was expensive to operate, Dr. Arora learned to use it overnight after the regular workday ended. His early studies included children living near a mining community. In their tooth-growth patterns, he could see exposure levels change as families moved from one location to another. The record was there. The next challenge was making that record available much earlier in a child’s life.

When the Science Became Personal

Around the same time, Dr. Arora and his wife became parents to triplet daughters after being told that having children was unlikely. One daughter experienced developmental and learning differences, and autism was one of the possibilities the family was asked to consider.

Dr. Arora was surprised that the evaluation relied so heavily on questionnaires and behavioral observations. His clinical and laboratory training had conditioned him to look for objective biological measurements. He began asking whether autism might leave a measurable biochemical pattern. His research team studied hair and teeth from children in multiple countries, including twins who shared the same genes but had different developmental outcomes. They examined patterns in how the body processed essential and toxic elements over time.

Hair offered an important advantage. Children usually do not lose baby teeth until age five or six, but hair can be collected during infancy. Using robotic and laser technology, the researchers analyzed tiny points along a strand of hair to map biological patterns across time.

A peer-reviewed study published in 2022 evaluated hair samples across cohorts in Japan, Sweden, and the United States. In a blinded analysis involving 486 participants, the algorithm identified a biomarker associated with later autism with 96.4 percent sensitivity, 75.4 percent specificity, and 81.4 percent overall accuracy. The authors reported that the pattern could be detected in samples collected as early as one month of age. 

The Birth of ClearStrand-ASD

LinusBio has translated this research into ClearStrand-ASD, a prescription laboratory test intended to help health care providers rule out autism when it is a concern in children from one month through 10 years of age.

The distinction between screening, ruling out, and diagnosing is important. According to the current ClearStrand-ASD information, the test returns either a negative or non-negative result. A non-negative result does not confirm autism. It indicates that the child may need a more comprehensive evaluation. The test should be considered alongside developmental history, behavior, and professional clinical judgment.

The test is performed in a CLIA-certified laboratory, but it has not yet been cleared or approved by the U.S. Food and Drug Administration. An earlier version of the technology received an FDA Breakthrough Device designation, which allows closer communication with the agency and prioritized review during development. As the FDA explains, that designation is part of the review pathway and is not the same as FDA approval or clearance.

For Dr. Arora’s family, ruling out one possibility helped them investigate others. His daughter was ultimately treated for other conditions, including ADHD and anxiety. He described the transformation with unmistakable pride. A child who once struggled to speak when nervous later stood onstage and delivered a 20-minute presentation about Neil Armstrong. “Ruling out an incorrect diagnosis is often as good as finding the right diagnosis,” he said.

For parents, the larger message is not to wait if something feels different. The CDC recommends that developmental concerns lead to further evaluation and, when appropriate, early intervention. No single laboratory result should replace a full developmental assessment. ​

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What if a strand of hair could reveal a timeline of environmental exposures?

In this episode of Trust Me Mom (Season 2, episode 45 available on Spotify and Apple Podcasts), Dr. Manish Arora, environmental epidemiologist, exposure biologist, founder and CEO of LinusBio, professor at the Icahn School of Medicine at Mount Sinai, and father of triplet daughters, shares the personal and scientific journey behind his groundbreaking research.

Dr. Arora explains how growing up during a civil war and malaria epidemic sparked his interest in environmental health. He later discovered that the growth rings inside baby teeth and hair can preserve biological information about nutrients, chemicals, and environmental exposures over time.

We discuss the exposome, why the timing of an exposure can be as important as the amount, and how Dr. Arora’s experience with his neurodivergent daughter inspired his search for more objective ways to help families find answers earlier. Dr. Arora also explains the science behind ClearStrand-ASD, a hair-based laboratory test intended to help health care providers rule out autism, and Traced, a consumer wellness test that maps patterns involving essential and toxic elements.

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​Reading the Environmental Record in Hair

Dr. Arora’s team has also developed Traced, a direct-to-consumer wellness test designed to map patterns involving 15 essential, non-essential, and toxic elements across a 30-day period. The current test uses a small sample of hair and reports elements such as zinc and copper, as well as lead, arsenic, and cadmium.

Unlike ClearStrand-ASD, Traced is not a medical diagnostic test and does not require a prescription. Its purpose is to provide information about environmental exposure patterns and help people consider practical changes in their homes and routines. If you’d like to try the test, use promo code TRUSTMEMOM at checkout to receive 30% off.

Dr. Arora believes the time-based pattern is what makes the approach useful. A blood test usually captures a particular moment. Hair grows over time, allowing his platform to examine a sequence and look for repeated changes that may correspond with a routine, location, or recurring activity.

The report is meant to guide questions, not provide a diagnosis. If a result suggests possible lead exposure, for example, a parent should speak with a health care professional. The CDC recommends a blood lead test to determine whether a child has been exposed to lead and to guide appropriate medical follow-up.

From Invisible Worry to Practical Action

Conversations about toxins can quickly become frightening, especially for parents already carrying a heavy mental load. Dr. Arora does not want families to panic or attempt to eliminate every possible exposure. Most homes are monitored for temperature and smoke, he noted, but not for the many other environmental factors families encounter. Better information can help parents focus on specific concerns instead of worrying about everything at once.

Potential sources vary widely. Lead may be found in deteriorating paint or contaminated dust in older homes. Cadmium can come from tobacco smoke and certain industrial sources. Pesticides may enter the home through lawn care, pest control, or residues. PFAS and other chemicals have been used in some nonstick, stain-resistant, and water-resistant products.

The goal is not perfection. It is informed, manageable action.

Parents can start by:

1. Talking with a pediatrician promptly about developmental concerns rather than waiting for certainty.
2. Asking about a blood lead test if a child may have been exposed, particularly in an older home or through another known risk factor.
3. Keeping the home and car smoke-free.
4. Addressing peeling paint and dust safely, especially in homes built before 1978.
5. Following product labels carefully and reducing unnecessary pesticide use when practical.
6. Improving ventilation during cooking, cleaning, painting, or home projects.
7. Making one realistic change at a time instead of trying to overhaul the entire household overnight.

Dr. Arora uses a business metaphor that feels surprisingly reassuring: “Everybody is the CEO of their own house.” Parents cannot control every part of a child’s biology or environment. They can, however, make thoughtful decisions about many of the products, habits, and conditions inside their homes.

A More Empowering Way to Think About Environmental Health

One person may experience significant effects from an exposure that appears to have little impact on someone else. That does not make the risk imaginary or the science irrelevant. “Humans are different,” Dr. Arora said. “There is a range of responses to these environmental toxins.”

It is equally important not to turn environmental health into parental blame. Research into the exposome is an effort to understand complex interactions, not a reason for mothers or fathers to believe they caused a child’s developmental differences. Good environmental health is not about raising children inside a perfect bubble. It is about replacing invisible worry with better questions, reliable clinical testing when it is indicated, and practical changes that a family can sustain.

For Dr. Arora, that is where decades of science and his experience as a father meet. His work began with a child’s view of chemicals drifting through the air, continued through long nights beside a nuclear reactor, and became deeply personal when his own daughter needed clearer answers. Now he hopes the tools developed from that journey will help other families move from uncertainty toward informed action.