Dr. Raquel Amaro Silva
SURGEON PONTEVEDRA
Collegiate No. 362607457
Graduated in Medicine and Surgery from the University of Santiago de Compostela with a Master's Degree in Aesthetic Medicine and Trichology and Hair Micrograft. She currently works as a doctor and hair surgeon in Hospital Capilar as head of the headquarters Hospital Capilar Pontevedra.
Hair loss can have multiple causes, and one of them is thyroid gland disorders. Both hypothyroidism and hyperthyroidism can disrupt the hair growth cycle and contribute to diffuse hair loss. However, in many people, thyroid dysfunction is not the only factor involved and can coexist with other hair problems, such as... androgenetic alopecia, an telogen effluvium or nutritional deficiencies.
The good news is that when thyroid disease is diagnosed and properly managed, hair loss usually slows down and hair can gradually regain some of its lost density. To achieve this, it's not enough to treat the hormonal imbalance; it's also important to identify any other factors that may be contributing to hair loss.
In this article you will discover how the thyroid affects hair, what symptoms may suggest a thyroid problem, what tests help confirm the diagnosis, and what options exist to restore hair health.
If you're looking for a quick answer, these are the most important ones:
If the drop persists, it is important rule out other associated causessuch as androgenetic alopecia or nutritional deficiencies.
The answer is simple: Yes, thyroid problems can cause hair loss. Thyroid hormones play an essential role in the functioning of the hair follicleWhen its levels are altered, the normal hair cycle also changes and a greater number of follicles enter the shedding phase prematurely.
This process doesn't happen immediately. Hair loss typically appears several weeks or even months after the thyroid dysfunction begins, as the hair follicle needs time to respond to hormonal changes. Unlike other types of alopecia, thyroid-related hair loss usually affects the entire scalp evenly. In addition to losing density, the hair may become thinner, drier, more brittle, and less shiny.
However, having a thyroid problem doesn't necessarily mean it's the only cause of hair loss. Other factors, such as androgenetic alopecia, telogen effluvium, or certain nutritional deficiencies, often coexist. Therefore, a complete medical diagnosis is essential before starting any treatment.
Although both disorders can cause hair loss, they do so through different mechanisms.
When the thyroid produces fewer hormones than needed, metabolism slows down, as does hair follicle activity. As a result, hair grows more slowly, becomes thinner, spends less time in the growth phase, and more follicles enter the resting phase.
In addition to hair loss, it is common for hair to become drier, coarser, and more brittle. Some people may also experience thinning of the outer third of the eyebrows, a characteristic sign of hypothyroidism.
These symptoms do not appear in all people or with the same intensity, but they can guide the doctor when accompanied by other signs of hypothyroidism, such as tiredness, weight gain or intolerance to cold.
In hyperthyroidism the opposite occurs: the excessive production of thyroid hormones accelerates numerous bodily processes, including the hair cycle, causing a greater number of follicles to enter the shedding phase prematurely.
The result is usually a diffuse loss of density accompanied by thinner and more fragile hair.
Among the most frequent symptoms of hyperthyroidism are unexplained weight loss, nervousness, tremors, palpitations, and heat intolerance.
Some autoimmune thyroid diseases can also affect hair health. Hashimoto's thyroiditis is the most common cause of hypothyroidism, while Graves' disease is a leading cause of hyperthyroidism.
In addition to hormonal imbalance, these conditions can coexist with other autoimmune diseases that affect hair, such as alopecia areata. Therefore, if hair loss continues despite controlled thyroid function, a complete evaluation is advisable to identify any other contributing factors.
It's not possible to determine the cause of hair loss simply by looking at the hair. Although there are some signs that may suggest a thyroid disorder, the diagnosis must be based on a medical evaluation and specific tests.
Thyroid-related hair loss typically presents these characteristics:
Es diffuse, without specific areas of baldness.
The loss of density appears in a progressive.
Hair tends to become more till, dry o brittle.
It is accompanied by other symptoms consistent with hypothyroidism or hyperthyroidism.
However, these symptoms can also appear in other types of alopecia. Therefore, attributing hair loss to the thyroid without a medical evaluation can delay proper diagnosis and treatment.
When there is suspicion that hair loss is related to the thyroid, the specialist performs a comprehensive assessment to confirm the origin of the problem and rule out other factors that may be influencing it.
The most common tests are:
Clinic historyto find out when the hair loss started, how it has progressed, and if there is a personal or family history.
Scalp examinationwhich allows for the assessment of the hair loss pattern and the detection of signs compatible with other alopecias.
Digital trichoscopy, a non-invasive test that analyzes the condition of the scalp and hair follicles with high magnification.
Depending on each patient, it may also be advisable to analyze other parameters related to hair health, such as levels of iron, ferritin, vitamin D, zinc or certain hormonal alterations.
One of the most frequent mistakes is thinking that hair loss has a single cause.
In reality, it's common for several factors to act simultaneously. A person with hypothyroidism may also experience androgenetic alopecia, telogen effluvium, iron deficiency, or nutritional deficiencies that perpetuate hair loss even after thyroid function is under control.
For this reason, simply treating the thyroid disease is not always enough to restore hair density.
Identifying all the causes involved allows for a much more precise treatment design and increases the chances of stopping hair loss and promoting hair regrowth.
En Hospital Capilar We perform Tricometabolic, an advanced hair diagnostic designed to identify the different factors that may be causing hair loss.
This study combines:
Analysis of 27 biomarkers, to detect hormonal, nutritional and metabolic alterations related to hair health.
Digital trichoscopy, which allows for highly accurate analysis of the scalp and hair follicles.
Specialized medical assessment, to interpret all the results together and establish an individualized diagnosis.
Thanks to this approach, it is possible to determine whether the thyroid disorder is solely responsible for the hair loss or if there are other factors that also require treatment.
With TricometabolicWith our advanced hair diagnosis, we analyze the factors that may be causing hair loss to design the most suitable treatment for you.
Request your hair diagnosis and discover what is really affecting the health of your hair.
In most cases, hair loss caused by a thyroid disorder is reversibleWhen hormone levels return to normal, the hair cycle usually stabilizes and hair gradually begins to recover its growth.
For this reason, treatment should always focus first on controlling the thyroid disease. As long as the hormonal imbalance persists, any treatment aimed solely at the hair will have limited effectiveness.
Once thyroid function has stabilized, the specialist will assess whether the hair loss is due exclusively to the thyroid or if there are other causes that also require treatment.
Recovery is not immediate. The hair follicle needs time to complete its process. Lifecycle and resume normal hair production.
Although each person evolves differently, the usual evolution is similar to this:
Between 2 and 3 months: the drop usually begins to stabilize once the thyroid disorder is controlled.
From 3 to 6 months: an improvement in hair density, thickness and quality begins to be noticeable.
These timeframes are indicative and depend on factors such as the duration of the disease, the response to treatment, and the existence of other hair problems.
This is one of the most frequently asked questions, and the answer is simple: Hair does not respond immediately to hormonal changes.
The follicles that began their shedding phase during the thyroid imbalance continue their cycle until it is completed, so it is normal for hair loss to persist for a few weeks or even months after thyroid function is normalized.
However, if the hair loss persists for a prolonged period or continues to increase, a new medical evaluation is advisable.
When density does not improve after controlling thyroid disease, it is important to investigate whether there is another associated problem.
In clinical practice, it is relatively common for thyroid disorders to coexist with other causes of hair loss, such as:
Androgenetic alopecia.
Prolonged telogen effluvium.
Iron, ferritin or vitamin D deficiencies.
In these cases, treatment will depend on the diagnosis. The specialist may recommend various therapeutic options to stimulate hair growth, such as Platelet Rich Plasma (PRP) or the hair mesotherapy, provided there is a medical indication.
It's not advisable to start treatment on your own without knowing the cause of your hair loss, as each type of alopecia requires a different approach. Find out if your thyroid is the cause of your hair loss or if there's another factor that also needs to be addressed.
Although hair loss due to thyroid problems usually improves once the disease is under control, there are situations in which it is advisable to consult a specialist as soon as possible.
It is advisable to seek medical evaluation if:
The decline lasts for more than three months or continues to increase.
Hair continues to lose density despite having controlled thyroid function.
Areas appear with more noticeable hair loss or a different pattern than usual.
The hair becomes progressively thinner and more fragile.
There is a family history of androgenetic alopecia.
Hair loss is accompanied by symptoms that may indicate hormonal imbalances or nutritional deficiencies.
Early diagnosis allows for earlier identification of the cause of hair loss and increases the chances of preserving hair density, especially when several factors are involved at the same time.
Yes. Both hypothyroidism and hyperthyroidism can disrupt the hair growth cycle and contribute to diffuse hair loss. In most cases, hair loss improves when thyroid function normalizes, although other factors, such as androgenetic alopecia or telogen effluvium, are also frequently involved.
Yes, in most cases. When thyroid disorder is diagnosed and treated correctly, hair usually gradually recovers its normal growth cycle. Recovery will depend on factors such as the duration of the disease, the condition of the hair follicle, and the presence of other causes of hair loss.
It's not possible to determine this solely based on the appearance of the hair. Diagnosis requires a medical evaluation that includes a medical history, a scalp examination, and blood tests to assess thyroid function. In some cases, it's also necessary to rule out other causes of alopecia or nutritional deficiencies.
Yes. If hair loss continues after thyroid function has normalized, there may be another underlying cause, such as androgenetic alopecia, telogen effluvium, or a nutritional deficiency. In these cases, a hair assessment can identify the cause of the hair loss and determine the most appropriate treatment.
Yes, some people may notice a temporary increase in hair loss during the first few weeks after starting treatment or after a dose adjustment. This is usually a temporary process related to the body's adjustment and not a permanent effect of the medication. If hair loss persists, consult your doctor.
It may be helpful in certain patients to promote hair growth, but it does not correct the underlying thyroid dysfunction. Before starting any treatment, it is important to identify the cause of the hair loss and check for other factors that may also require treatment.
Request a hair diagnosis and find out if your thyroid is the cause of your hair loss or if there is another factor that also needs to be addressed.