Levothyroxine hair loss is a common concern among individuals taking this medication for thyroid conditions. Many patients notice hair thinning or increased shedding shortly after beginning treatment. Sometimes, the dose of your thyroid medication may be too high.

For those managing hypothyroidism, levothyroxine is a common prescription aimed at restoring thyroid hormone levels. Yet, amidst the routine of daily medication, a distressing issue can emerge: hair loss and hair thinning. You may be wondering if levothyroxine can cause hair loss.

If you notice hair thinning and/or loss after taking levothyroxine, you are not alone. Many patients report thinning hair or increased shedding after starting levothyroxine, raising concerns about whether this treatment is contributing to their hair woes (*). If you’re worried about your hair while on levothyroxine, you’re not alone—let’s shed some light on this important topic and discuss the steps you can take to address it.

Key Takeaways

• A common side effect of Levothyroxine thyroid medication is hair loss
• Monitoring thyroid hormone levels and nutritional support are vital for managing hair loss while on levothyroxine.
• If hair loss persists beyond 12 months of treatment, it’s recommended that you work with a functional medicine practitioner to dig deeper into what might be causing your hair thinning and hair loss. You can learn more about some of these other hormones in this article, Hormones that cause hair loss
• T3 thyroid hormone directly influences hair growth, promoting the growth phase of the hair cycle (anagen) and potentially inducing hair follicle activity in the dormant phase (telogen).
• Studies show that both T3 and T4 stimulate hair matrix keratinocyte proliferation and alter the production of keratins within the follicle, impacting hair growth.

Thyroid Disease, Levothyroxine, and Hair Loss

Thyroid disease refers to any condition that affects the thyroid gland, a small but powerful organ located at the base of the neck. This butterfly-shaped gland produces the hormones T3 and T4, which regulate many vital processes in the body, including metabolism, bowel activity, energy levels, and hair growth.

When it comes to thryoid hormones both T3 and T4, thyroid hormones, are involved in hair growth, but T3 is the more active and potent form. T3 directly stimulates hair follicle activity, while T4 is the precursor and storage form, needing to be converted to T3 for its effects. This is important to remember because many people who have hair loss have normal T4 levels, but upon further testing, have very low levels of T3 or free T3. For this reason, I recommend that everyone who has hair loss have their T3 thyroid hormone levels tested.

The Role of the Thyroid Gland in Hair Growth

The thyroid gland plays a central role in maintaining healthy hair growth(*). It produces thyroid hormones, which are essential for the normal function and development of hair follicles. These hormones help regulate the hair growth cycle, which includes the anagen (active growth), catagen (transitional), and telogen (resting) phases. When the thyroid gland is underactive and doesn’t produce enough thyroid hormones, the hair growth cycle can be disrupted, causing more hair follicles to enter the resting phase and resulting in thinning hair and hair loss.

On the other hand, an overactive thyroid gland can also upset the balance of the hair growth cycle, sometimes leading to rapid hair loss and noticeable changes in hair texture. Both underactive thyroid and overactive thyroid conditions can cause hair to become dry, brittle, or thin. Understanding how the thyroid gland and its hormones influence the growth cycle of your hair is key to diagnosing and treating thyroid-related hair loss, and can help restore healthy hair growth over time.

Understanding Levothyroxine and Hair Loss

Levothyroxine is the standard treatment for both underactive thyroid and Hashimoto autoimmune disease, a condition where the immune system attacks and destroys the thyroid gland, leading to hypothyroidism. Studies show that Hashimotos is the number one cause of hypothyroidism in the United States(*),(*). Since Hashimotos leads to hypothyroidism, you can probably understand why Hashimotos disease can lead to thyroid hair loss. While Hashimoto’s can cause diffuse hair loss, it can also be linked to alopecia areata, an autoimmune condition where the body attacks hair follicles, leading to patchy hair loss in specific areas(*).

Proper thyroid hormone levels are essential for the human hair growth cycle. Having enough thyroid hormone is crucial for healthy hair growth and to prevent patients from losing hair. Both hyperthyroidism and hypothyroidism can disrupt this cycle, leading to hair issues such as thinning or diffuse hair loss. Patients may lose hair from the scalp, and scalp hair is often affected. It’s not uncommon for thyroid patients to experience hair loss, changes in hair texture, or alterations in hair pigmentation as symptoms of their thyroid dysfunction and thyroid conditions.

Some patients experience temporary hair loss initially as the body adjusts to new hormone levels during levothyroxine treatment, and some will continue to lose hair as a side effect of levothyroxine or because they are overmedicated with thyroid hormones. Keeping hormone levels within the optimal range helps minimize hair loss during treatment.

Side effects of Levothyroxine that your doctor didn’t warn you about.

How Levothyroxine Affects Hair Growth

Both T3 and T4, thyroid hormones, are involved in hair growth, but T3 is the more active and potent form. T3 directly stimulates hair follicle activity, while T4 is the precursor and storage form, needing to be converted to T3 for its hair-stimulating effects(*).

Clinical tip: If your Free T4 levels are normal, get tested for Low T3. Learn more about Low T3 here

When you take Levothyroxine, this medication attempts to mimic the natural thyroid hormone T4. The problem for many women and men comes down to the conversion of T4 into T3. Remember T3, the active form of thyroid hormone, which plays a crucial role in regulating hair growth. If you are not converting T4 into T3, despite having normal T4 levels, you will have a delay in the growth phase and an increase in the shedding phase.

Hair growth usually starts again after thyroid hormone levels become stable. Nutrient deficiencies, such as low levels of biotin, iron, vitamin C, Collagen, Silicon, sulfur, or vitamin D, can also contribute to hair loss during this period. Balanced sex hormone levels are essential for new hair growth and restoring hair density. Learn more about nutrients and vitamins needed for hair growth.

Common Side Effects of Levothyroxine

Like any medication, levothyroxine comes with its own set of side effects. Other common side effects include:

• Weight gain
• Abdominal pain
• Diarrhea
• Muscle weakness
• Bone Loss
• Brain Fog
• Dementia
• Bloating (SIBO)
• Dry skin

Thyroid-related hair loss generally manifests as diffuse hair loss across the scalp rather than in localized bald spots (*). Although distressing, this thyroid hair loss usually resolves once thyroid hormone levels are stabilized, especially when addressing the underlying root causes of the thyroid disorder.

Body responses to levothyroxine can vary widely. Incorrect medication dosing, whether too high or too low, can exacerbate hair loss. Overmedicated with levothyroxine can induce hyperthyroidism, leading to hair thinning, brittle nails while an insufficient dose can maintain a low thyroid state, both of which can cause hair loss.

Why Does Levothyroxine Cause Hair Loss?

The initial hair loss associated with levothyroxine treatment often occurs during the first month due to the body’s adjustment to new thyroid hormone levels. This period of adjustment can temporarily disrupt the hair growth cycle, leading to hair shedding.

Incorrect dosage is another significant factor. Taking too much levothyroxine can lead to an overactive thyroid, which may cause rapid hair loss and thinning hair(*). Conversely, an insufficient dosage can keep the thyroid gland underactive, perpetuating hair loss associated with hypothyroidism. In some people, thyroid medication all by itself will be the culprit for hair thinning or hair loss.

What does Thyroid Hair loss look like?

Thyroid-related hair loss often presents as a general thinning across the entire scalp and eyebrows, rather than distinct bald spots. This diffuse hair loss can develop slowly, making it less noticeable at first, especially in areas where the hairs are thinning, potentially indicating telogen effluvium. Thinning of the outer one-third of the eyebrow is a strong indicator of thyroid issues and should prompt your health care provider to test you.

Unlike alopecia areata, which causes patchy hair loss and is sometimes linked to autoimmune thyroid disease, thyroid-related hair loss usually results in diffuse thinning.

If you notice clumps of hair coming out as you brush, it may be a sign to get tested for a thyroid disease and Hashimotos. Unlike other types of hair loss that cause patchy bald spots, thyroid-related hair loss typically presents as a uniform thinning across the scalp.

Managing Hair Loss While Taking Levothyroxine

Managing hair loss while taking levothyroxine involves a multi-faceted approach. Identifying the pattern of thyroid disease, monitoring and optimizing your thyroid hormone levels, especially T3 thyroid hormone levels, ensuring nutritional support for hair health, and adopting gentle hair care practices are key strategies to mitigate hair loss and promote hair regrowth. In addition to nutrition, other supplements may also support hair health.

Monitor Thyroid Hormone Levels

To minimize hair loss while taking levothyroxine, it is crucial to:

• Know your thyroid numbers and understand your thyroid lab ranges. At what level do you feel your best? Keep a diary of your thyroid hormone numbers and how you feel.
• Test for Thyroid Antibodies- There are two antibodies you want to have tested. You can learn more about thyroid antibodies here.
• Adjust your medication dosage as needed.
• Conduct regular blood tests.
• Monitor your thyroid hormone levels, including TSH, Total T3, Free T3, and Reverse T3 levels, to ensure your thyroid hormone dosage is appropriate and effective.

Nutritional Support for Hair Health

Diet is foundational, but diet alone is usually not enough. A balanced and nutrient-rich diet supports a healthy diet and healthy hair growth. Nutritional deficiencies, especially iron deficiency, are common causes of hair loss in thyroid patients. If you are a vegetarian or have/had heavy menstrual cycles, be sure you get your iron and ferritin levels tested. Ensuring that your ferritin levels are at least 70 ng/mL is necessary for optimal hair health. Iron, zinc, vitamin D, Collagen, and amino acids are all common vitamin and mineral deficiencies seen in women.

As mentioned in today’s article, as well as past articles, vitamins and supplements can also support hair health. Vitamin D, B vitamins, Collagen, Sulfur, Silica, biotin, EPA from Fish Oil, and vitamin C are particularly beneficial in promoting hair growth and strengthening hair strands.

Functional Medicine and Thyroid Hair Loss

Functional medicine offers a holistic approach to managing thyroid hair loss by focusing on identifying and addressing the root causes of thyroid dysfunction and related hair issues. Unlike conventional medicine, which often centers on symptom management, functional medicine practitioners aim to optimize overall thyroid care through personalized treatment plans that consider diet, lifestyle, environmental factors, and nutrient status.

In cases of thyroid hair loss, functional medicine emphasizes the importance of achieving an accurate diagnosis through comprehensive laboratory tests, including thyroid antibody tests, to detect autoimmune diseases such as Hashimoto’s thyroiditis. This autoimmune condition is a common cause of an underactive thyroid gland and can significantly contribute to hair thinning and diffuse hair loss.

Functional medicine also advocates for managing other symptoms associated with thyroid issues, including weight changes, fatigue, and dry skin, through integrative therapies and lifestyle modifications. Collaborating closely with a healthcare provider experienced in thyroid care ensures that medical treatments are tailored to each individual’s needs, improving outcomes for both thyroid health and hair restoration.

Alternative Treatments for Thyroid-Related Hair Loss

Several alternative treatment options can help manage thyroid-related hair loss. Options include:

• Minoxidil: an FDA-approved topical treatment that helps stimulate hair follicles and regrowth.
• Microneedling: a technique that has shown promise in promoting new hair growth.
• Red light therapy: another method that may improve hair density.

Microneedling and low-level light therapy work by enhancing blood circulation to the hair follicles, thereby supporting healthy hair growth and human hair follicle functions.

Here’s What You Should Remember About Today’s Article on Levothyroxine and Hair Loss

Managing hair loss while taking levothyroxine involves understanding the causes, recognizing symptoms, and implementing effective solutions. Regular monitoring of thyroid hormone levels, nutritional support, and gentle hair care practices can significantly mitigate hair loss. While T4 levels are important, be sure you get your T3, total T3, Reverse T3, and thyroid antibodies tested when you have thyroid-related hair loss. Remember, T3 is the active thyroid hormone that regulates the cycle of hair growth. We want more hair to grow and less shedding. Alternative treatments like minoxidil and microneedling can also offer additional support.

Frequently Asked Questions

Why does levothyroxine cause hair loss?

Levothyroxine may cause hair loss for a number of reasons.

#1- Levothyroxine itself can cause hair loss: Regardless of the dose, some individuals may experience hair shedding as a side effect of levothyroxine treatment.

#2 Undemedicated: If the levothyroxine dose is too low, the stimulation of hair follicles from thyroid hormone may be insufficient, leading to hair loss.

#3 Overmedicated: Taking too much levothyroxine can result in a state of hyperthyroidism, which is also associated with hair loss. Patients who are taking thyroid hormone replacement or who have Hashimotos disease are often overmedicated with thyroid hormones. Learn about the symptoms of being overmedicated from thyroid hormone replacement here

What Does Thyroid Hair Loss Look Like?

Thyroid hair loss typically appears as diffuse hair loss, meaning the thinning occurs evenly across the entire scalp rather than in isolated patches. This type of hair loss can make your hair look less dense overall, and you may notice more hair coming out when you brush or wash it. In cases of hypothyroidism, hair loss can also affect the outer one-third of the eyebrows, which is a unique sign of thyroid dysfunction.

Unlike other forms of hair loss that cause bald spots or patches, thyroid hair loss tends to be more subtle and widespread. If you’re experiencing diffuse hair loss or notice changes in your hair’s thickness and volume, it could be a sign of an underlying thyroid problem. Recognizing these patterns can provide clues on what further action steps are needed to support both your thyroid health and your hair.

How can I manage hair loss while taking levothyroxine?

To manage hair loss while taking levothyroxine, it’s crucial to know your numbers and optimize your thyroid hormone levels, provide adequate nutrition for hair health, and adopt gentle hair care practices. Taking these steps can help mitigate hair loss effectively. You can learn more in this article about hair care practices if you have or suspect thyroid-related hair loss.