The Science Behind Thinning Hair, Brows and Lashes

The Science Behind Thinning Hair,
​Brows and Lashes and
How to Treat It

Jim Markham, founder and CEO of ColorProof Color Care Authority, notes that, according to the American Academy of Dermatology, 40 percent of American women will experience thinning hair at some point in their lives. But the causes—and therefore prevention and treatment techniques—can vary greatly. Here, we check in with leading haircare, lash and brow experts to determine how beauty pros can best proceed when faced with clients who crave a dose of added fullness.

Root Causes
Heather Ka’anoi, artistic director for John Paul Mitchell Systems, notes that aging, stress, hormonal imbalance, excessive styling, inadequate nutrition, pregnancy, an unhealthy scalp, heredity, breakage, dramatic weight loss, hypothyroidism, or an iron deficiency can cause hair loss. To identify the range of causes, Syrenthia Quinones, brand education manager for Nioxin, sums them up in six general categories.

Genetics: A family predisposition to thinning hair involves natural, age- related hormonal changes caused by the conversion of testosterone into the toxin dihydrotestosterone (DHT), which can be inherited from a mother or father.

Stress and Trauma: Stress can produce increased levels of testosterone, which converts to DHT, interrupting the hair growth cycle. Stress also constricts the blood supply through the capillaries, restricting oxygen, nutrient uptake and vitamins to the follicle.

Health: Underlying issues may include a malfunction of the hormone- producing thyroid or the natural changes women experience after pregnancy and menopause.

Environmental: Air and water pollutants, chlorine, metals, and minerals left in the hair and on the scalp—as well as pseudo-estrogens and toxins from within our bodies—can contribute to thinning.

Medication: Hair follicles are extremely sensitive to changes in the body—e.g. hormonal therapies like birth control, steroids, specific chemotherapies, and medications for blood pressure, diabetes, heart disease, or acne.

Nutrition and Diet: High consumption of animal fats, rapid weight loss and liquid protein diets can result in a lack of amino acids, biotin, iron, protein, and zinc—all essential for healthy-looking hair.

With these main culprits in mind, experts can break down how each affects the hair. Amir Yazdan M.D., founder of GroMD, explains that hormonal concerns, generally caused by elevated levels of DHT or menopause, create an imbalance of estrogen and progesterone, while conditions like polycystic ovarian syndrome (which can increase testosterone levels) or a thyroid imbalance may be to blame. April Cox, national trainer for Eufora, adds that everyone has testosterone in their bodies, as well as the enzyme 5-alpha reductase—but when testosterone and 5-alpha reductase couple together, that forms DHT, creating havoc on scalps, thinning the hair bulb and, in turn, creating thin hair and lock loss.

​Markham remarks that at various times of life, the capability of hair follicle stem cells decreases, inhibiting the ability to regenerate the cells responsible for new growth. Rising levels of DHT cause follicles to shrink and produce thin, atrophied hair (and eventually stop producing new hair altogether). Stem cells, which contain the chemical messengers responsible for hair production, increasingly fail as we age, and the follicle is unable to generate a new, healthy growth phase—resulting in aging scalp tissue, thinning hair and graying. “There’s also poor microcirculation and buildup. A poor blood supply results in sluggish cell turnover, leading to the buildup of sebum and dead skin cells that plug the follicle, preventing hair growth,” Markham notes. “Finally, there’s the failure of new growth to anchor: As tissue repair mechanisms fail, the new, weakened hair is unable to anchor properly and begins to fall out.”

To complicate matters further, Michelle Blaisure, product development director for Bosley Professional Strength, reports that hair loss is often multifactorial; your client could have a myriad of causes at play, including genetics. “About 20 percent of women thin due to an inherited condition known as female pattern hair loss—the same inherited predisposition (androgenetic alopecia) that causes up to 66 percent of men to lose their hair by age 60,” Blaisure details. “Androgenetic alopecia (AGA) is genetic predisposition causes the follicle in the crown and hairline to be sensitive to DHT, which, over time, shortens the hair life cycle, producing finer and weaker tresses, and can lead to changes in density. Men can go completely bald, often starting in their late teens or early 20s, while women experience di used thinning and may notice it in their mid-30s and 40s, when perimenopause starts.” Additionally, aging causes the hair growth cycles to slow, leading to a higher percentage of hair staying in the resting cycle—which, over time, leads to density and diameter changes: less hair, texture alterations, and weaker, drier, frizzier locks as hair loses its lipid layer.

Stress, a more common agent for hair loss in women, causes an increase in cortisol (the stress hormone), which over time “steals” hormones and nutrients the body needs to function well, leading to imbalance and deficiencies. “Since we don’t need hair to live, hair is last in line to get what it needs to grow in a healthy manner,” Blaisure explains. “Any type of traumatic event can also disrupt the hair cycle, leading to sudden excessive shedding (typically happening about three months after the event), but this will usually self-correct after a few months.” Additional culprits, she adds, can be chemical processes (think relaxers and bleach) if they cause damage to the scalp, leading to inflammation, breakage and hair loss; this can even extend to overuse of dry shampoo.

Health states or conditions also play a role: During pregnancy, hormone levels are high, but after childbirth, hormones return to their normal range—so all of the hair that didn’t fall out during pregnancy suddenly sheds at once. “ is also starts at about three months and usually self-corrects over time,” Blaisure notes. “Alternatively, many autoimmune disorders can cause hair shedding, and women seem to be more prone to these conditions.” Dr. Yazdan points to autoimmune conditions—a classification of conditions wherein the body attacks itself, which can include destroying the hair follicles—such as alopecia areata, frontal fibrosing alopecia and many more—as culprits. “Medications such as hormone replacement and birth control pills, steroids and, of course, chemotherapy, may cause hair loss, but differently in different clients,” adds Blaisure. Side effects of medications or chemotherapy treatments can generally be reversed if treated early, Dr. Yazdan explains, and notes that trauma, such as traction alopecia, accidents, surgeries, etc., can lead to short-term loss that can pass over time. Furthermore, Blaisure says, studies show that deficiencies in certain nutrients—namely vitamins C, D and B12, and minerals such as iron, zinc and omega-3 fatty acids—may contribute to hair loss. And, as hair is part of the skin structure, when the scalp receives sun damage, this injury can also impair the follicle.

​Finally, according to Bridgette Hill, aka “The Scalp therapist,” the location of the thinning can assist with determining if the cause is reactional or genetic. “Thinning around the hairline generally indicates a genetic predisposition, while allover thinning with no definitive bald patches typically points to reactional thinning,” Hill details. “The hair loss plan and products to treat reactional thinning will be needed temporarily, whereas a genetics-related hair loss plan and products would involve a lifetime change in her overall hair regimen.”

Read more of the article here for information on Preventative Measures, Extensions & Wigs, and Lash & Brow Losses.