10 Reasons Your Hair Thins

Thinning hair doesn't happen just because. There are a whole host of factors that can cause your hair to look sparse. Here's what's going on. 

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1/10

Your Genes

Englewood Cliffs, NJ, dermatologist Jeffrey Rapaport, MD, says that your genes are probably the most common cause for thinning hair. “As women get older, it’s normal for them to start to see thinning. When genetics play a role, we sometimes see the thinning much earlier on or it’s more intensified.”


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Your Hormones

Anything that alters your hormone levels—think birth control, menopause or pregnancy—can be responsible for hair that’s thinner than normal. Plano, TX, plastic surgeon Joseph Yaker, MD, says thinning hair is especially common in menopausal women because estrogen levels diminish. “The hormone estrogen is essential for protecting the hair.” Hormone-related disorders like polycystic ovary syndrome can impact the thickness of hair, too.

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Having a Baby

During pregnancy, hair is thick, shiny and voluminous. But post-pregnancy, it’s not uncommon for the hair to begin temporarily thinning out (and even breaking) due to a shift in hormones. About three months after delivery, hormones send the hair from an active, growing state into a resting one. For the most part, once your hormone levels even out, your hair should return back to normal. 


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Damaged Stem Cells in Hair Follicles

A rather new discovery in the world of thinning, the more damage (predominantly caused by aging) that occurs to the stem cells that live in the hair follicles, the more likely it is for those stem cells to turn into skin. Years of this transfer causes the follicles to shrink in size to the point that there is more skin than hair in the area, leading to patches of thinning hair or even bald spots.


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Excessive Amounts of Vitamin A

One of the more under-the-radar causes of thinning hair is taking too many supplements with vitamin A, which sends the hair growth cycle into a tailspin. However, once you stop taking high levels of the vitamin, your body will revert back to baseline and your hair should continue to grow regularly.


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A Lack of Protein

Going vegetarian or vegan may do wonders for your body, but chances are it won’t do much for your hair. While not everyone who forgoes animal-based sources of protein experiences thinning hair, it’s not uncommon to see signs of thinning and hair loss because protein is often limited. To reverse the effects, take a protein and iron supplement or start to add reliable protein sources, like beans, quinoa and tempeh, into your diet.


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Stress

Any type of emotional or physical stress can send your hair into a temporary state of disarray and here’s why. When your body is stressed, an uneven number of hairs transfer into the resting phase all at once. Then, when those hairs fall out, more than normal amounts are shed.


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Medical Conditions and Autoimmune Disorders

When the immune system has to work overtime to keep symptoms of certain diseases at bay, the body may not be able to sort out what’s going on and mistake hair as something foreign and harmful to the body. Palo Alto, CA, facial plastic surgeon Jill Hessler, MD, says that low thyroid levels can lead to hair loss. Hair thinning and hair loss caused by autoimmune disorders, also known as alopecia areata, is one of the harder types of thinning to treat. 


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Sudden Weight Loss

Dropping a serious amount of weight extremely fast (think 25 pounds in one month) can cause trauma to your hair, leaving it thin and weak. It’s not the weight loss itself that causes it, but rather the lack of vitamins, nutrients and healthy fats that you may be depriving yourself of that change the texture of your hair.


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Overstyling and Abusing Your Hair

Everything in moderation is the best approach to take when it comes to your hair. “Some hair types can’t tolerate the same amount of heat styling as others, but you need to know what your hair can withstand,” says Bumble and bumble stylist and educator, Carrie Hill. “Use medium heat instead of high heat and give your hot tools a break by using them every other day instead of every day.”

2 Comments
  • Jeffrey A Rapaport MD
    Posted on

    Please watch your Vitamin D levels and iron deficiency. Many people have hair loss due to these reversible problems. Best, Dr R.

  • Jeffrey A Rapaport MD
    Posted on

    A few other important causes of hair loss include low iron, low Vitamin D and tight hair styling.