5 Common Causes of Hair Loss, According to a Trichologist

September 09, 2022
Marisa Petrarca
By: Marisa Petrarca | Makeup.com by L'Oréal
person touching hair

Hair loss is a lot more common than you might think. For context: It's completely normal to shed between 50 and 100 hairs daily, according to the American Academy of Dermatology (AAD). But when it starts to feel excessive — and (or) your hair seems thinner — you should book an appointment with a dermatologist or a trichologist.

After all, hair loss could be due to various causes, from too-tight hairstyles and nutrient-restrictive diets to genetics. Ahead, we break down five leading causes of hair loss with expert insight from William Gaunitz, FWTS, certified trichologist and founder of Advanced Trichology, and Shab Reslan, a trichologist and hair expert based in New York City. 


One of the most common causes of hair loss is a hereditary condition called androgenic alopecia, according to Gaunitz. It occurs gradually with aging, recognized by a “general thinning of specific areas of the scalp,” and it affects “more than 50 million men and 30 million women in the United States,” per NYU Langone Health.

Gaunitz sees the most positive results in addressing androgenetic alopecia using "internal and external modalities including nutritional supplements and a topical tincture." Without getting *too* science-y, the former "addresses the amount of dihydrotestosterone (DHT) binding to the hair follicle receptor," which is what is responsible for hair loss, while the latter "disrupts the binding of DHT at the receptor site." 

Nutrient-Deficient Diet

"If your diet lacks essential nutrients such as zinc, magnesium, vitamin A, iron and B vitamins, your hair will not grow optimally, and you could be weakening the cells in your hair follicles responsible for hair growth,” says Reslan. If you’re unsure if you’re deficient, reach out to your healthcare provider. They may recommend a blood test to determine if and where you’re deficient. 

Hormonal Changes

According to Reslan, certain hormonal changes can cause temporary hair fall. For example, she mentions that it’s common to experience hair loss after getting off birth control, during the postpartum period, or during menopause due to irregular changes in estrogen. 

We should more broadly discuss this natural cause of hair loss, stresses Reslan. After all, "raising awareness of natural causes of hair shedding can help women get through these challenging situations."


Stress is a temporary form of hair loss. "Inflammation created in the body due to high stress causes the hair system to shut down and prematurely push hair into the resting phase of its growth cycle," she explains. "This phase can last a few months, which is why the actual shedding from stress-induced hair loss does not occur until at least three to four months after a specific episode."

So long as you decrease your stress levels and treat yourself to "proper health, diet, and scalp maintenance," the hair will grow back," says the pro.

Too-Tight Hairstyles 

Did you know that your hairstyle could cause hair loss? Yup, it's called traction alopecia, and it sometimes occurs if you frequently wear your hair tightly pulled back (i.e., ponytails, tightly braided hair and up-dos). The solution is simple, though: Reduce the tension by loosening up your hairstyle, when possible, or at the very least, reduce the amount of time your hair is styled tightly.

Since hair loss can be the result of many different factors, it’s always best to speak to a trained medical expert, like your healthcare provider or dermatologist, about your concerns.


Photo: Chaunte Vaughn

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