Hair Falling Out? These Are the Top Causes in Women

Mercey Livingston
Medically Reviewed
March 11, 2020

Hair loss in women is no joke—seeing more hair than you’d like swirling down the drain, in your brush, or on your bathroom counter can be really upsetting. But it’s a common issue that doesn’t always warrant an alarm—it’s normal to lose some hair each day (about 100 strands to be exact.)

So why is your hair falling out and when should you be concerned? If you’re losing clumps of hair or notice that your ponytail is thinner, or your hairline is changing, it may be time to talk to your doctor about finding potential underlying causes.

Hair loss is a common concern that conventional medicine does not always have the best answers for. Luckily, at Parsley Health, your doctors and coaches will take things one layer deeper and help look into many factors, like your blood work to see what could be going on. It’s all about seeing things through a lens of optimization, versus just trying to find a disease that you can diagnose.

Below, Darcy McConnell, MD , a physician at Parsley Health New York explains some of the common causes of hair loss in women and what you can do to help find the exact cause and treatment options.

Top causes of hair loss in women


Everyone experiences stress at some point, but prolonged or periods of extreme stress can really take a toll on your body. This may be a reason why your hair is falling out.

“The first thing that you should think about with new onset hair loss is stress. If you are under a crazy amount of stress then your body will shunt all of its energy to your vital organs to preserve nutrients for less necessary functions like growing hair,” Dr. McConnell explains.

The way your hair loss shows up or the pattern is happens in is also important to note and bring up to your doctor. “The pattern of hair loss can also tell you something about what is causing it.

Hair loss that results in generalized thinning is more commonly due to stress, nutrient deficiencies and medications,” Dr. McConnell says.

Autoimmune disease

If your hair loss shows up in patches, your doctor may test for alopecia areata, an autoimmune condition that can resolve in a year with proper treatment. This can be done by taking a biopsy if your hair follicle.

Autoimmune conditions typically coincide with inflammation , so figuring out where the inflammation is coming from- whether it is your gut, a hidden infection, toxin exposure, or your diet is key,” Dr. McConnell says.

“There are also a lot of supplements that help to reduce inflammation which can help while you are finding that root cause. Some of my favorite anti-inflammatory supplements are curcumin, fish oil, and Vitamin D ,” Dr. McConnell says.

Hormones and Iron deficiency

Female hair loss often has roots in biochemical and hormonal changes related to the menstrual cycle.

“One of the biggest causes for female hair loss is iron deficiency or even just sub-optimal iron levels. We lump this in with hormonal hair loss because iron deficiency in premenopausal women is so common because they lose blood every month from their menstrual cycles, making them more prone to iron deficiency and levels that are far from optimal,” Dr. McConnell explains.

The iron deficiency can then create a vicious cycle of sorts, because the lack of iron can then make your periods worse . “Having iron deficiency can also make your periods heavier and further exacerbate the deficiency that is present. In order to check your iron levels you want to make sure that your doctor not only looks at your hemoglobin and hematocrit levels but also runs a full iron panel as well as a ferritin level,” Dr. McConnell says.

If you do have labs that show sub-optimal iron levels , your doctor may prescribe an iron supplement. You can also bump up your iron levels through food, but this is a bit harder if you lean plant-based because the iron in meat is more bioavailable. Good animal sources of iron are grass-fed beef, chicken, and oysters.

If you don’t eat meat or seafood, you can add vitamin c (like a lemon squeeze) to your plant sources of iron to help with absorption.

Finally, if your iron levels are low, it’s important to look at what hormone imbalances could be behind the issue . Heavy periods are likely the result of imbalances like estrogen dominance.

If you do have estrogen dominance, or high levels of circulating estrogen in relationship to progesterone, your doctor can help you in several ways.

“DIM and I3C are two supplements that can help detoxify estrogens, but your doctor will also want to check your other detox pathways like how you methylate your hormones and what your progesterone levels look like in case low progesterone is actually the real issue,” Dr. McConnell says.

You can also use nutrition to help with estrogen dominance. Certain foods like cruciferous vegetables and broccoli sprouts help with the detoxification of estrogens by the liver, so adding these liver loving foods into your daily meals can be a great start.

Polycystic Ovarian Syndrome (PCOS)

Polycystic ovarian syndrome or PCOS is another common hormonal condition that can contribute to female hair loss.

PCOS is a condition in which women do not ovulate or ovulate irregularly. PCOS is rooted in metabolic dysfunction, where either insulin is too high or there is inflammation present that causes a disruption in metabolism and a hormone imbalance,” Dr. McConnell says.

When insulin levels are elevated, it can increase the amount of testosterone produced, which can cause hair loss in women.

If that’s the case, your doctor may suggest certain supplements like saw palmetto, zinc, vitamin D, and nettle root. These herbs and nutrients help with excess testosterone levels, Dr. McConnell explains.

Hypothyroidism or low thyroid function

Your thyroid is an extremely important endocrine gland in your body that regulates many different functions in your body, like your mood, brain function, digestion and more. Hypothyroidism is when your thyroid doesn’t produce enough thyroid hormone, which can result in many symptoms including hair loss.

To rule out a thyroid issue, ask your doctor for a full thyroid panel. Many doctors will only want to check TSH (thyroid stimulating hormone) but TSH is sometimes not enough to detect a thyroid problem. A full thyroid panel should include: TSH, free T3, free T4, anti-thyroglobulin and anti-thyroid peroxidase antibodies, and reverse T3. All of these things are necessary to get a full picture of your thyroid health.

Nutrient and mineral deficiencies

If you are experiencing hair loss, it’s a good idea to ask your doctor to run full nutrient, micronutrient, and mineral tests to detect any possible deficiencies. Just like iron deficiency can cause hair loss, zinc deficiency can also lead to hair loss.

“Zinc deficiency can affect your immune system as well so if you are commonly sick, are tired, or experience rashes like dermatitis, you may want to get your zinc levels checked,” Dr. McConnell says.

If you’re wondering why your hair is falling out, don’t get discouraged by all the potential causes. At Parsley Health, we often help women with hair loss to identify the root cause and find the right treatment plan. Working on a lifestyle that supports overall good health with proper nutrition, exercise, and potentially adding some anti-inflammatory supplements can go a long way while you work with your health providers to investigate the problem and kick hair loss for good.

Mercey Livingston

Mercey Livingston is a health and wellness writer and certified Integrative Nutrition Health Coach. She is passionate about translating expert and science-based wellness advice into accessible and engaging content. Her work is featured on Well+Good, Women's Health, Business Insider, and among others. When not writing, she enjoys reading, trying out new recipes, and going to new workout classes all over New York City.

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