Everything You Need to Know About Thyroid Related Hair Loss

Diffuse thinning tends to appear when hair loss is linked to thyroid issues. Shedding is typically even across the scalp, instead of patches or specifically at the crown.

If you notice other symptoms alongside this type of hair loss, such as dry skin, fatigue, weight changes, cold sensitivity and mood or menstrual changes, it may indicate an underlying thyroid imbalance.

Both an underactive thyroid and an overactive thyroid can disrupt the normal hair growth cycle, pushing more hair into the shedding phase.

Hair may appear dull or feel dry and brittle, or you may have eyebrow thinning, particularly on the outer edges.

Hair loss from thyroid appears as overall thinning across your entire scalp. It doesn’t typically present as patchy or cause a receding hairline, and hair may suddenly appear thinner than usual with increased dryness and breakage.

Another classic sign of an underactive thyroid is hair thinning on the outer portion of your eyebrows. Also known as Hertoghe’s sign, it occurs because the thyroid gland does not produce enough thyroid hormones. This reduces the hair growth cycle and as a result, hair struggles to grow on that area of the eyebrow because it’s more susceptible to the effects of low thyroid hormone levels.

Unlike other types of hair loss, such as alopecia areata, thyroid-related shedding tends to be gradual but persistent, often only improving once thyroid hormone levels are properly managed through treatment.

There are a few signs to look out for which may help you identify thyroid-related hair loss, and whilst self-assessment can’t replace medical testing, it can help you understand whether your symptoms are consistent with thyroid-related shedding so that you can seek advice from a healthcare professional.

Here’s how to assess it yourself:

• Is the hair loss thinning all over, rather than patchy or receding in one area?
• Is your hair becoming unusually dry, brittle, or more prone to breakage?
• Is the outer third of your eyebrows thinning or disappearing?
• Are you losing more than 50–100 hairs per day consistently?
• Has the hair loss coincided with other unexplained changes in your body, such as fatigue, weight gain or loss, irregular periods or mood shifts?
• Gently run your fingers along your lower neck, near the collarbone, for any unusual swelling or lumps, which may indicate an enlarged thyroid.

If you answer yes to any of this a checklist, it’s worth booking an appointment to see a GP for further investigations and tests.

It’s important to remember that some of these symptoms can be down to other reasons, but it’s always best to find out the cause so that if treatment is required, it can be administered sooner rather than later.

Try to keep a log of hair shedding, any changes in scalp or skin condition and your energy levels. This will be helpful for your GP.

The NHS offers the Thyroid Function Blood Test, which is the most common and reliable test. It measures levels of thyroid-stimulating hormone (TSH) as well as free T3 and free T4, which are the key hormones produced by the thyroid.

Hypothyroidism or underactive thyroid usually shows as high TSH with low T4, while hyperthyroidism or overactive thyroid shows as low TSH with high T3 or T4. Hormone levels are compared to what’s normal for a healthy person of your age.

Additional blood tests may check for thyroid antibodies such as thyroid peroxidase antibodies (TPOAb) or TSH receptor antibodies (TRAb) if autoimmune thyroid disease is suspected.

A thyroid scan may also be used to search for lumps, also known as nodules, on your thyroid.

Medical interventions for hair loss caused by thyroid disorders

Medical interventions usually begin with addressing the underlying hormonal imbalance.

Once diagnosed, your doctor will typically prescribe thyroid hormone replacement such as levothyroxine for hypothyroidism or medications to regulate an overactive thyroid, such as antithyroid drugs for hyperthyroidism.

Hormone levels should begin to stabilise over a few weeks to a few months, which should result in your hair growth cycle going back to normal. However, because hair growth naturally takes time, noticeable changes in thickness or reduced shedding may take three to six months to see.

In addition to treating the thyroid, some doctors may recommend supportive interventions like topical minoxidil (Regaine) to stimulate regrowth or nutritional supplements if deficiencies like iron, zinc or vitamin D are contributing to the condition.

A holistic treatment plan is often recommended for autoimmune-related issues such as Hashimoto’s or Graves’ disease, incorporating dietary changes and stress management to help support hair recovery.

Using hair care remedies alongside your medical treatment plan can help minimise damage and boost healthy regrowth.

Sulphate-free shampoos give your hair a deep cleanse without stripping the strands of moisture, while deep conditioners and hair oils help to boost moisture and restore elasticity.

Don’t forget that being selective with hair tools and using the right techniques is just as important as shampoos and conditioners. Try not to overuse heat styling tools, pat instead of rub when drying your hair and use a wide-tooth comb when styling. These can all help to minimise unnecessary damage to compromised hair. A scalp massage can help boost blood flow and support follicle health, too.

Also, focus on care from the inside out by ensuring that your diet is rich in key nutrients like protein, iron, zinc, and vitamins D and B12.

It’s important to remain consistent with any of these adjustments, alongside proper thyroid treatment. It will help to preserve existing hair and promote a healthier regrowth phase over time.

Ongoing monitoring and adjustments are needed to keep hormone levels in check and hair growth stable. The recommendation for rechecking thyroid hormone levels is initially every six to eight weeks after starting thyroid medication, as your body adjusts to the medication.

If symptoms like fatigue, hair shedding, or mood changes are persistent, your doctor may adjust your medication based on updated TSH, T3, and T4 levels.

Keep a record of any continued hair loss or new symptoms because this could signal the need for adjustments to your dosage, additional tests or any underlying conditions alongside the thyroid condition.

Once your thyroid is well-managed, check-ins may become less frequent. Patience is essential when it comes to regrowth; it can take up to six months to show any improvement, even after hormone levels normalise.

It’s important to seek professional advice if you’re noticing ongoing or sudden shedding, particularly when accompanied by weight changes, mood changes, fatigue, dry skin and irregular periods. You may need medical attention if this persists for more than a few weeks or doesn’t change with your own self-care.

If you’re already receiving thyroid treatment but hair shedding hasn’t improved after several months, a review of your hormone levels, medication dosage or nutrient status may be needed.

If you’re looking to begin hair loss treatment during thyroid recovery or for other causes, Chemist Click offers a convenient and fully regulated online prescription service to get you started quickly. We provide a free online health assessment reviewed by UK-registered prescribers to determine your eligibility for treatments such as Finasteride for men and topical Minoxidil.

Once approved, prescription medications are dispensed with discreet next-day delivery across the UK, ensuring privacy and convenience. To get started, simply complete the online consultation, which includes a medical questionnaire tailored to your condition.

How long does it take for hair to grow back after hyperthyroidism?

Noticeable regrowth takes around three to six months, beginning once thyroid hormone levels are balanced out with treatment.

What thyroid test shows if you are losing hair?

The Thyroid Function Test (TFT) measures levels of TSH, free T3, and free T4 hormones. Abnormal results such as high TSH with low T4 in hypothyroidism or low TSH with high T3/T4 in hyperthyroidism can indicate a thyroid imbalance that may be causing hair loss.

How do you know if hair loss is from thyroid?

Diffuse thinning across the scalp rather than patchy bald spots can indicate thyroid relation, especially alongside other symptoms like fatigue, weight changes, dry skin, or mood swings. As well as this, thinning of the outer third of the eyebrows is a classic sign of thyroid dysfunction.

What does thyroid hair look and feel like?

Thyroid hair often looks thin and brittle, with a noticeable loss of volume and shine. It can feel dry, coarse, and more fragile, making it prone to breakage.

How does having thyroid problems make you feel?

It can make you feel fatigued, you may notice weight changes, feel cold or overheated, and experience mood swings like anxiety or depression.

Other common symptoms include muscle weakness, hair loss, irregular menstrual cycles and swelling in the neck if the thyroid is enlarged. These symptoms vary depending on whether your thyroid is underactive or overactive.