11 Hidden Causes of Thinning Hair in Women (and what to do about it)

If you’re a person who has experienced or is experiencing unexplained hair loss, you know how devastating it can feel. And the truth is that up to 40% of women experience hair thinning by the age of 40, but as a society, we don’t talk about it a lot.

Although it’s normal to lose up to 100 hairs a day, when you feel clumps of hair running down your back after shampooing, see it on your pillow in the morning, and glean shocking glimpses of your scalp when your hair is wet or unstyled, you know something is not right.

The good news is that thinning hair, at any age, doesn’t have to be something you just live with or try and cover up. There is a reason for it, and oftentimes you can get your beautiful locks back.

Having experienced thinning hair myself (more than once!), and helped many patients get to the bottom of their hair loss problems I’ve learned thinning hair in women is often rooted in one of the following health issues.

First, let’s review the normal cycles of hair growth:

Every hair follicle is independent and goes through the hair growth cycle at different times.

Anagen: This is your hair’s growth period. Hair grows actively from the roots for an average of 2-7 years before the hair follicles become dormant.

Catagen: This is the transitional hair growth cycle. This phase on last for 2-3 weeks on average and during this time, hair stops growing and detaches itself from the blood supply. It is then named a club hair.

Telogen: This is the resting phase. Club hairs rest in the root while new hairs begin to grow beneath it. This phase lasts about 3 months. After this time, the resting club hairs begin to fall out in order to let the new hairs grow through the hair follicle.

Now onto the causes of hair loss.

#1: Stress

I listed this first because stress is a very common cause of thinning hair in women.

Stress is also a contributing factor to nearly every type of chronic disease—many of which can cause hair loss (more to this to come).

A recent study from Harvard found that stress hormone modifies a gene in the dermal papillae of the hair follicle and can actually stop growth.

Stress causes a couple of different types of hair loss:

Telogen effluvium is a very common cause of hair loss. It is a reversible condition that occurs after a highly stressful life event or shock, such as a surgery, birth, car accident, death of a loved one, divorce, etc., and causes a large number of hair follicles to enter a rest phase, causing them to fall out several months later.

Another type of hair loss is alopecia areata, a condition in which your immune system attacks your hair follicles and can also be triggered by extreme stress. This is characterized as sudden hair loss that presents as one or more circular bald patches throughout the scalp.

The obvious—but not necessarily easy—first step is to reduce day-to-day stress and to recover from the trauma of past events.

I recommend one or more self-care practices such as exercise, meditation, prayer, gardening, spending time in nature, being with friends and loved ones, journaling, biofeedback (my saving grace), dancing, doing artwork, and breath work be practiced daily.

For trauma healing, many people find that help from a professional therapist or counselor combined with emotional detox modalities like the Emotional Freedom Technique, meditation, and optimizing their nutrition paves the way for true healing.

Supplements that can help with stress response include:

Magnesium
Ashwagandha
Rhodiola
B vitamins
Chamomile

#2: Thyroid trouble

If you’re experiencing hair loss, especially if combined with other symptoms like cold intolerance, insomnia, hormonal imbalance, weight issues, fatigue, mood swings, etc., there is a chance that your thyroid is involved.

In my functional medicine practice, I run a full thyroid panel to check for TSH, free T3, free T4, reverse T3, and thyroid antibodies (which are present in the case of an autoimmune thyroid disease such as Hashimoto’s), as any imbalance can cause symptoms like hair loss.

To learn more, check out: The Thyroid Tests Your Doctor is Missing…

#3: Hormonal imbalances

In addition thyroid hormone issues, other hormones like estrogen, progesterone, cortisol, DHT, insulin, growth hormone and testosterone play a key role in hair follicle health.

Symptomatology along with a detailed and comprehensive hormonal lab work is key to identifying and treating these issues effectively.

In my practice, I use the DUTCH (Dried Urine Test for Comprehensive Hormones) Test which measures levels of sex hormones (estrogen, progestrone, testosterone, etc.), stress hormones, sleep hormones, and even mood and nutrient markers via organic acids.

Two of the most important lifestyle changes you can make to help with hormonal imbalances include:

the removal of endocrine-disrupting chemicals from your home and kitchen,
and eating to support hormonal health.

Endocrine-disrupting chemicals are typically found in chemical-based household products (cleaners, air fresheners, personal care products, pesticides, laundry products, etc.) and foods high in pesticides and herbicides. I discuss this at length in my book: Bloom: 7 Steps to Reclaim Your Health, Cultivate Your Desires, & Reignite Your Spark.

Learn more about eating for hormonal health in: Top 5 Hormone Balancing Superfoods.

#4: PCOS (Polycystic Ovarian Syndrome)

PCOS is an all-too-common cause of infertility, affecting up to 12% of women of reproductive age.

Considered a chronic disease, it can cause cysts to develop on the ovaries. Irregular periods are often a tell-tale sign of PCOS, and women with PCOS are also often insulin resistant and have a higher risk of type 1 and 2 diabetes, heart conditions, weight-gain/obesity, and depression/anxiety.

The official “cause” of PCOS is unknown, but we know that women with PCOS can have an imbalance in androgens (male sex hormones), which is why it can cause thinning hair on the scalp.

We also know that excess insulin, low-grade inflammation and genetics can play a role.

All this said, if you’re diagnosed with PCOS, I want you to know there is hope.

In functional medicine, we always look for the root cause of a condition. In this case, we know PCOS is a hormonal-imbalance-related condition; but I’d take it a step further and investigate what’s causing the imbalance to begin with. And if we can get to the bottom of that and address it properly, it is possible to heal.

#5: Heredity

When you’re losing your hair it’s little consolation to be told, “It’s hereditary, deal with it.”

However, while heredity certainly can play a role we should always look a little deeper to try and determine why symptoms like thinning hair run in your family in the first place.

Was it due to a genetic mutation that affected how your mother or grandmother metabolized key nutrients essential to healthy hair? We can pinpoint this using nutrigenomics testing.

Was it an undiagnosed thyroid condition? Because a mother’s thyroid health can affect future generations.

Did mom or Grandma possibly have PCOS or hormonal imbalances?

So you see, heredity doesn’t have to be your destiny! The key is to find a good doctor trained in epigenetics to help you identify and treat any underlying genetic or inherited conditions.

#6: Nutrient deficiencies

It’s been said that our outer appearance is a reflection of our inner health. This is why ancient forms of medicine, such as Traditional Chinese Medicine and Ayurveda (the traditional medicine of India) train their practitioners to observe things like our nails, hair, tongues, eyes, and skin in order to diagnose ailments.

Insofar as hair health is concerned, the following nutrients are especially critical:

Iron with vitamin C
B-Vitamins—particularly Vitamin B12 and B7 (Biotin)
Vitamin D
Protein
Zinc
CoQ10
Copper

If you’re deficient or have insufficient levels of any of these, it can directly affect the appearance and thickness of your hair.

I’ve found in my practice that women often lack B-vitamins and iron due to absorption issues either rooted in gut infections or methylation issues, and/or due to blood loss from their periods.

The quality of your diet also plays an important role.

Thus, it’s a good idea to address any digestive, hormonal, and methylation issues if you suspect or confirm suboptimal levels.

The best overall defense against nutrient deficiencies is to eat the rainbow, which includes 7-10 servings of vegetables (emphasis on leafy greens) and 2-3 servings of fruit per day, have protein at every meal, get enough fiber, and focus on healthy fats.

I also recommend (ideally) having your nutrient levels checked, especially for iron or vitamin D, before beginning a supplementation program.

#7: Postpartum hair loss

As if having a new baby isn’t enough stress…the majority of women can expect to experience postpartum hair loss.

Why oh why does this happen? In a word: hormones!

More specifically, when you get pregnant your body experiences a surge in hormones, like estrogen, which prevent your hair’s natural daily shedding. Hence why most women enjoy gloriously thick and shiny hair during pregnancy.

However, after you give birth those hormones dip and begin to recalibrate…resulting in a “catch up” of all the hair shedding you missed out on during those 9 months gestation (yipee).

Thankfully, this is a temporary condition that typically resolves itself after a few months without any treatment.

If your hair loss seems really excessive, you can ask your doctor to check you for postpartum thyroiditis. However, for most women it peaks at 4 months postpartum and should stop before your baby’s first birthday.

What to do? Take good care of yourself, mama.

This means eating really well, resting as much as possible, practicing self-care, and going easy on your hair insofar as styling and blowouts are concerned (not that new mamas have much time to style their hair anyway!).

#8: Medications

Hair loss can be a side effect of many medications, including immune-suppressant drugs, chemotherapy drugs, antifungals, and drugs that deplete your body of essential nutrients.

One common example are birth control pills which have been shown to deplete zinc, magnesium, B6, B12, folate, and elevate homocysteine levels.

This is a perfect example of why it’s so very important to discuss any and ALL medication side-effects with your doctor and trusted pharmacist.

You can also use the free site: mytavin.com to calculate which nutrients your specific medication may deplete, then focus on beefing up those nutrients in your diet.

#9: Sudden or extreme dietary changes

Any time we change our diets radically, like drastically reducing calories or cutting out entire food groups, it has the potential to create enough stress and lack of nutrients to cause hair loss.

The most important thing is to use commonsense and always make sure any change in diet focuses on eating plenty of nutrient-dense foods. Generally, I do not recommend diets that demonize entire food groups, like carbs or vegetables or meat.

It’s also important to use detox cleansing and fasting as short-term strategies for healing—not long-term lifestyle changes, as our microbiome diversity and overall health benefit from a wide variety of foods.

#10: Chronic or acute illness or disease

Any type of acute or chronic disease that causes significant inflammation can contribute to hair loss.

This includes acute infections accompanied by high fever and a variety of autoimmune conditions.

There’s even new evidence that COVID-19 can cause hair loss in some people.

The tricky thing about chronic diseases is we often don’t realize we have one!

For example, Hashimoto’s produces little to no symptoms during the early stages, and there are plenty of people unknowingly living with inflammatory digestive issues, like intestinal permeability (aka: Leaky Gut Syndrome) or Irritable Bowel Syndrome, which have also been shown to cause hair loss.

The takeaway: if you have mysterious hair loss along with any other symptoms, no matter how mild like fatigue, indigestion, etc., definitely get yourself checked out by a functional medicine physician.

#11: Heavy metals

Heavy metal toxicity is a real modern problem that just isn’t talked about enough.

It’s caused by a variety of exposures to things like heavy-metal-based pesticides used on foods, coal pollution, lead, mercury, arsenic, and other metals found in municipal water supplies, and heavy metals found in foods like fish and even juice (to name but a few)!

Heavy metal toxicity can cause a variety of symptoms including neurological issues, sleep problems, autoimmunity, and (you guessed it) hair loss (“telogen effluvium” to be exact).

Fortunately, your toxicity level can be measured by specific lab work, and there are excellent therapies and nutritional strategies to help reduce body burden.

Where do I start?!

You just learned a lot of information about what could be causing your unexplained hair loss…so where the heck does a gal start?

My inclination is always to start with the low-hanging fruit, trust your intuition and go from there.

For example, if you know you’re stressed out most of the time it would be a good idea to start practicing some regular self-care.

Or, perhaps your hair loss coupled with low energy, insomnia, weight gain, digestive issues, etc. could be a clue that you need to get some lab work done to check for thyroid, hormonal, or nutrient imbalances.

The point is that thinning hair is usually a sign of a deeper issue…and that’s not something to be afraid of! Instead, I’d invite you to see it as an opportunity to take back control of your whole health and enhance your happiness.

You’re worth it!