Causes, Symptoms, and Treatment
for Thyroid Hair Loss

Written by Kathleen Morrison
Medically Reviewed by Andrea Sleeth WHNP-BC, MSCP

Key takeaways:

• Both hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) can cause hair loss.
• Thyroid hair loss typically looks like diffuse thinning all over your scalp rather than patchy bald spots, and may also affect -your eyebrows and body hair.
• Hypothyroidism often makes hair dry and brittle, while hyperthyroidism can make it fine and silky.
• Thyroid-related hair loss is usually reversible once your hormone levels are balanced with proper treatment.

Finding more hair in your brush than usual? Noticing your ponytail getting thinner? Before you spiral into a Google black hole, take a breath.

Hair loss can feel super personal and frustrating, but if your thyroid has been out of whack lately, it might be the culprit causing excessive hair shedding.

Whether you're dealing with an underactive thyroid (hypothyroid) or an overactive one (hyperthyroid), hair loss can be one of the first signs that something's up.

The tricky part? It can take a while for other symptoms to show, so your hair might be sending an SOS before you even realize there's a problem.

Can thyroid issues cause hair loss?

Yes, a thyroid disorder can lead to hair loss. Both hypothyroidism and hyperthyroidism can mess with your hair growth cycle and lead to noticeable thinning.

But, before we get all science-y about the how, let's give you a quick primer on the thyroid gland.

Your thyroid is a tiny butterfly-shaped gland in your neck that's basically the CEO of your metabolism. When it's out of whack—whether it's working overtime or slacking off—your whole body notices, including your hair follicles.

Now, how do thyroid problems cause hair fall?

Your hair grows in cycles. There's the growth phase (anagen), a transition phase (catagen), a resting phase (telogen), and a last shedding phase (exogen).

Normally, most of your hair is busy growing while only a small percentage is resting. But when your thyroid hormone production is out of balance, this rhythm gets disrupted.

Thyroid conditions can cause hair follicles to get pushed into the telogen (resting) and exogen phases (shedding), all at once. That's a condition called telogen effluvium.

So if you're losing more hair than usual and can't figure out why, it might be worth checking your thyroid levels.

Hypothyroidism vs hyperthyroidism hair loss

Quick thyroid 101. Two main thyroid conditions can mess with your hair: hypothyroidism and hyperthyroidism.

With hypothyroidism (the one that’s often linked to weight gain), your body slows way down. That includes the tiny processes that help your hair grow.

Cell turnover in your hair follicles takes a hit, new strands take longer to come in, and the hair you already have is more likely to fall out. The result? Thinner hair and more shedding than usual.

With hyperthyroidism (the one commonly associated with weight loss), everything speeds up instead. Your hair actually grows, but the growth cycle is on fast-forward.

While new hair is growing, the accelerated cycle means hyperthyroidism can cause more shedding than your body can keep up with.

What does thyroid hair loss look like?

Wondering if your hair loss is thyroid-related? The pattern and texture changes can give you some clues.

Unlike male or female pattern baldness (which tends to follow a specific pattern), hair loss caused by thyroid disease shows up as diffuse thinning across the scalp.

You won't see distinct bald patches. Instead, your hair just looks and feels thinner overall.

Here are the key symptoms of thyroid hair loss to look for:

Overall hair thinning:

Your hair may look less full everywhere rather than in specific spots. You might notice your part looking wider or your ponytail feeling smaller.

Texture changes:

With hypothyroidism, scalp hair often becomes dry, coarse, and brittle. With hyperthyroidism, it might feel unusually fine, soft, or silky.

Eyebrow thinning:

This is a classic hypothyroidism sign. Look for thinning or loss at the outer third of your eyebrows (toward your temples). Dermatologists actually have a name for this—the Hertoghe sign.

Body hair loss:

Thyroid hair loss may extend to body hair, too. You may see thinning hair or increased hair shedding all over your body, including your arms, legs, and down there, too!

Increased shedding:

You might notice more hair than usual in your brush, shower drain, or on your pillow. While losing 50–100 hairs a day is normal, thyroid issues can ramp that up significantly.

If you're checking boxes on this list, it's worth paying attention to other symptoms that might point to a thyroid issue.

Signs your thyroid might be behind your hair loss

Hair loss rarely shows up alone when your thyroid is involved. Your body usually drops other hints, too.

Knowing what to watch for can help you connect the dots and get to the bottom of what's going on.

Hypothyroidism (underactive thyroid) symptoms

When your thyroid isn't producing enough hormones, everything slows down. Along with hair loss, you might notice:

• Constant fatigue, even after plenty of sleep
• Unexplained weight gain
• Feeling cold all the time (hello, extra blankets)
• Dry skin that feels rough or flaky
• Constipation
• Brain fog or trouble concentrating
• Depression or low mood
• Muscle weakness or aches
• Irregular periods
  

Hyperthyroidism (overactive thyroid) symptoms

When your thyroid is in overdrive, your metabolism speeds up. You might experience:

• Unexplained weight loss, even with increased appetite
• Rapid or irregular heartbeat
• Nervousness, anxiety, or irritability
• Excessive sweating or feeling overheated
• Trembling hands
• Trouble sleeping
• More frequent bowel movements
• Lighter or less frequent periods

If your hair loss is paired with any of these symptoms, your thyroid is definitely worth investigating.

And if you're approaching perimenopause or menopause, keep in mind that hormonal shifts during this time can also affect thyroid function. So it's extra important to get checked out.

Wisp treatment options are available only after consultation with a licensed medical professional. You should consult with your healthcare provider before starting a new supplement or treatment regimen. Individual results may vary.

How to test your thyroid function

Suspecting your thyroid is to blame? You can test your thyroid at home.

But a simple blood test can give you more concrete answers.

Thyroid testing is quick, straightforward, and can be done through your doctor or even at-home testing options.

Here's what a typical thyroid panel measures:

• TSH (thyroid-stimulating hormone): This is usually the first test your doctor will order. High TSH often indicates hypothyroidism, while low TSH can point to hyperthyroidism.

• T4 (thyroxine): Measures the main hormone your thyroid produces. Low levels suggest hypothyroidism; high levels suggest hyperthyroidism.

• T3 (triiodothyronine): Another thyroid hormone that can help confirm a diagnosis.

• Thyroid antibodies: These tests can detect autoimmune diseases like Hashimoto's thyroiditis, lupus erythematosus, or Graves' disease, which are common causes of hair loss through thyroid dysfunction.

Blood tests can provide a clear picture of what's going on and help guide treatment.

What can you do about your thyroid-related hair loss?

Here's the best news about thyroid-related hair loss: it's usually reversible. Once your thyroid hormone levels are back in balance, most people see their hair start to recover.

Medical treatment for thyroid disease

The only way to put a stop to thyroid-related hair loss is to treat the thyroid condition.

For hypothyroidism, doctors typically prescribe synthetic thyroid hormone (usually levothyroxine) to replace what your body isn't making.

For hyperthyroidism, treatment options include antithyroid medications, radioactive iodine therapy, or, in some cases, surgery.

Your healthcare provider will work with you to find the right approach based on your specific situation.

It's worth noting that some thyroid medications can temporarily cause additional hair shedding as your body adjusts. Don't panic. This is usually temporary and improves as your levels stabilize.

Hair growth support options (after your thyroid is treated)

Once your thyroid levels are balanced with proper medical care (read that again), you can look at some supplemental hair treatments to help give your hair follicles a little nudge.

These include:

• Topical Minoxidil (OTC): A well-studied over-the-counter topical treatment that helps stimulate hair growth and extend the hair growth phase.

• Low-Level Laser Therapy (LLLT): Some studies show modest increases in hair density compared with baseline through LLLT, though results are mixed, and more research is needed.

• Oral Minoxidil: Oral minoxidil is a prescription alternative to topical minoxidil that some doctors prefer for people who don’t tolerate topicals. It’s increasingly used for diffuse thinning, although not specific to thyroid hair loss.

  
  

Supporting your hair from the inside out

While you're working on balancing your thyroid, there are things you can do to help support healthy hair growth:

• Check your iron levels: Iron deficiency is super common, especially in women, and may cause hair loss to worsen. If your levels are low, your doctor might recommend iron supplements. An anemia blood panel can help you figure out if this is a factor.

• Eat a nutrient-rich diet: Focus on protein, omega-3 fatty acids (hello, salmon!), and foods rich in vitamins A, C, D, and E. Leafy greens, eggs, nuts, and lean meats are all hair-friendly choices.

• Avoid products high in iodine: Kelp and other "thyroid support products" that contain iodine may interact with your treatment plan. So, it's best to avoid them.

• Be mindful of biotin: While biotin supplements are popular for hair health, heads up—biotin can potentially cause interference with thyroid blood test results. If you're taking it, let your doctor know and stop it a few days before any thyroid testing.

• Manage stress: Chronic stress can worsen both thyroid issues and hair loss. Finding ways to decompress. Whether that's yoga, walks, or binge-watching your favorite show, stress relief can genuinely help.

  
  

Be gentle with your hair

While your hair is recovering, treat it kindly:

• Skip harsh chemical treatments and heat styling when possible
• Use a gentle, moisturizing shampoo
• Avoid tight hairstyles that pull on your roots
• Let your hair air dry when you can
• Use a wide-tooth comb to minimize breakage
  

Autoimmune thyroid conditions & alopecia (the hair loss double whammy)

Autoimmune thyroid conditions can also trigger additional hair loss conditions, including alopecia areata. So, it’s a two-for-one situation no one asked for.

Hashimoto’s thyroiditis & hair loss

Hashimoto’s, the most common cause of hypothyroidism, happens when your immune system attacks your thyroid. The inflammation lowers hormone production and can target hair follicles directly. This often leads to more severe shedding than non-autoimmune hypothyroidism, plus a higher risk of alopecia areata during flare-ups.

Graves’ disease & hair changes

Graves’ disease causes hyperthyroidism by overstimulating the thyroid. Excess hormones speed up the hair cycle, resulting in fine, brittle hair, increased breakage, and texture changes. Stress, insomnia, and treatment side effects may worsen telogen effluvium.

The alopecia areata connection

Studies have suggested a link between alopecia areata and thyroid. Many people with alopecia areata also have thyroid disease because both are autoimmune. The good news? Hair often regrows once thyroid levels stabilize (which is where medication may help).

When to see a healthcare provider

Hair loss can feel isolating and stressful, but you don't have to figure it out alone.

If you're noticing significant shedding that's been going on for more than a few weeks, especially if it's paired with other symptoms like fatigue, weight changes, or mood shifts, it's time to talk to someone.

You should also reach out if your hair loss isn't improving after several months of thyroid treatment, or if you notice sudden or dramatic changes causing your hair loss to worsen.

Your provider can check your hormone levels, adjust your treatment if needed, and rule out other possible causes.

Keep in mind that certain medications, genetic factors, and even other conditions can affect hair growth alongside thyroid issues, including autoimmune conditions like alopecia areata, polycystic ovary syndrome (PCOS), or nutritional deficiencies.

Thus, getting a proper diagnosis is key to finding the right solution.

Getting your hair (and your health) back on track

Losing your hair can feel like losing a part of yourself, but on the bright side, when your thyroid is the culprit, it's usually fixable.

With proper testing, the right treatment, and a little patience, most people with thyroid-related hair loss see real improvement.

Your body is constantly communicating with you. Thinning hair, fatigue, and other symptoms are just its way of waving a flag. Listening to those signals and getting your thyroid checked can put you on the path to feeling like yourself again.

Wisp makes taking charge of your health simple. From at-home testing to online consultations with licensed providers, we're here to help you get answers and personalized care, all from the comfort of your couch. Because you deserve to feel confident in your health and your hair.

This blog post is for informational and educational purposes only and should not be taken as professional advice. Always consult with a qualified professional before making any decisions based on the information provided here.