Thyroid hair loss: tests, treatment and regrowth
An underactive or overactive thyroid can contribute to hair loss. Thinning often affects the scalp more broadly, sometimes alongside a change in hair texture. However, dry hair, a more noticeable parting or extra strands in a brush cannot identify thyroid disease: diagnosis brings together symptoms, examination and appropriate blood tests.
When a thyroid disorder explains the shedding, treating it may allow the hair to improve, usually gradually. Any other factors contributing to thinning also need attention, rather than expecting everyone to recover in the same way. A medical assessment should precede decisions about hair loss products or a hair transplant in Turkey, which cannot treat a thyroid imbalance.
Why can thyroid disease affect the hair?
The thyroid is a small gland at the front of the neck. It produces hormones including T4 and T3, which help regulate many tissues, including hair follicles. Too little or too much thyroid hormone can disrupt hair renewal, so changes are not confined to one type of thyroid disorder.
The 2023 review by Hussein and colleagues brings together clinical observations and experimental research into these relationships. It describes changes in hair growth and structure in both hypothyroidism and hyperthyroidism. Experiments involving cells or follicles cannot, however, predict how much hair an individual will lose or how fully it will recover.
Shedding associated with a general health problem can take the form of telogen effluvium, with more hairs falling out following a disturbance to their renewal. The visible change may occur some time after its trigger. The date you notice extra shedding therefore does not necessarily mark the start of a thyroid imbalance.
There is no single percentage that applies to everyone with thyroid disease. Published studies involve different populations and methods, sometimes recruiting people who have specifically sought help for hair loss. Their findings cannot turn a thyroid diagnosis into a reliable prediction of an individual’s future hair density.
Which symptoms can suggest an underactive or overactive thyroid?
With hypothyroidism, hair may become drier or coarser, alongside diffuse shedding. Unusual tiredness, feeling cold, constipation or weight gain may accompany these changes. The NHS explains that symptoms often develop gradually, which helps explain why people may notice them at different times rather than as one clear group.
Hyperthyroidism can also be associated with finer hair and reduced density. Palpitations, trembling, difficulty tolerating heat or weight loss can provide useful clues during a consultation. Tiredness can occur in either condition: it cannot distinguish an overactive thyroid from an underactive one.
These combinations offer clues rather than a checklist for diagnosing yourself. NICE notes that a single symptom is a poor predictor of thyroid dysfunction; a clinician considers the wider picture and your medical history. Our article about hair loss and tiredness explains why these two concerns can also have separate causes.
Arrange an appointment if shedding continues, thinning progresses or you notice changes in your general health. Tell the professional managing your thyroid condition if you are pregnant or planning a pregnancy, as your care may need adjusting. Do not wait for possible hair regrowth before seeking advice about new or worsening symptoms.
Can the pattern of hair loss identify its cause?
A general reduction in hair volume can be compatible with thyroid dysfunction, but several other conditions can look similar. The appearance of your hair or the strands left in the shower cannot reveal your hormone levels. The term alopecia means hair loss; it does not identify a single cause or establish that the thyroid is involved.
Thinning of the eyebrows can sometimes accompany hypothyroidism, without being specific to it. Similarly, clearly defined bald patches should not automatically be attributed to a hormonal imbalance. Alopecia areata can coexist with autoimmune thyroid disease and requires its own assessment, as Hussein and colleagues discuss in their review.
Hashimoto’s thyroiditis and Graves’ disease are autoimmune conditions affecting the thyroid. Having either condition does not mean that the antibodies measured during thyroid investigations are destroying your hair follicles. Diffuse shedding and alopecia areata have different mechanisms, even when more than one autoimmune condition is present.
Androgenetic alopecia can also develop alongside a thyroid problem, particularly if thinning began well before other symptoms. The clinician assesses the distribution of hair loss and the condition of the skin. Painful, inflamed or rapidly thinning areas need examination rather than waiting for thyroid tests to explain every change.
How should you prepare for a consultation and thyroid tests?
Put together a simple timeline covering hair changes, other symptoms, recent illness and alterations to medication. If you already have a thyroid condition, bring previous results with their dates and a list of your prescriptions. This history helps distinguish recent shedding from longstanding thinning and guides the choice of investigations.
NICE guidance generally recommends starting with TSH when thyroid dysfunction is suspected in an adult and there is no suspicion of pituitary disease. TSH is a hormone that directs thyroid activity. Depending on the result, the laboratory or clinician adds free T4 and, in some circumstances, free T3 to the investigation.
In practice, a raised TSH usually leads to measurement of free T4, while a low TSH prompts assessment of free T4 and free T3. This is not a protocol to follow independently. Children, situations where the pituitary gland may be involved and other particular circumstances require an approach suited to that context.
Antibody tests can help clarify the cause of suspected or established thyroid dysfunction, such as TPO antibodies in some investigations for hypothyroidism. They are not universal tests for hair loss. An ultrasound examines the structure of the gland when indicated; it does not replace hormone measurements and is not routinely needed because someone is losing hair.
Biotin and borderline results: why interpretation matters
Mention every supplement you use, including products marketed for hair and nails. Biotin can interfere with some thyroid blood tests, producing results that appear higher or lower than they really are, depending on the assay. NICE added this precaution to its guidance in 2023: both the clinician and laboratory need to know about its use before interpreting results.
Do not decide how long to stop a supplement from a general instruction found online. The appropriate advice depends on factors including the product, the amount taken and the laboratory method. Bringing the packaging or a photograph of the label provides more useful information than describing it simply as “hair vitamins”.
A result just outside the reference range does not establish that the thyroid explains all your hair loss. Some conditions described as subclinical involve an abnormal TSH while thyroid hormone levels remain within their expected range. Decisions about monitoring, repeat testing or treatment then depend on several clinical and laboratory factors, rather than the hair alone.
Conversely, reassuring thyroid results do not necessarily end an investigation into thinning. Depending on your history and examination, a clinician may consider other causes, including nutritional factors, medicines or a scalp disorder. An acute illness can itself alter thyroid test results, so the circumstances of a blood sample matter alongside the number on the report.
Which treatments may improve thyroid-related shedding?
Treatment first addresses the thyroid condition and your wider health. Where hypothyroidism requires hormone replacement, NICE and the NHS describe levothyroxine as the standard treatment. Adjustments depend on medical follow-up, blood tests and symptoms; the number of hairs you shed is not enough to determine the right dose.
For hyperthyroidism, options may include antithyroid medicines, radioactive iodine or surgery, depending on its cause and your circumstances. These treatments are not interchangeable and are not chosen according to the appearance of your hair. A specialist can explain the appropriate option and how it will be monitored.
When thyroid dysfunction contributes to shedding, controlling it may help the hair improve, but it will not necessarily address a separate hair disorder. Follow-up therefore needs to distinguish changes in blood results, general symptoms and the hair itself. Results returning to their reference range do not prove that every change in density had the same cause.
There is no reason to add T3, thyroid extracts or a product advertised as “thyroid support” yourself to speed up regrowth. NICE does not recommend routine liothyronine use or natural thyroid extracts for primary hypothyroidism. Continued shedding calls for reassessment rather than independently increasing thyroid hormones.
Could levothyroxine be contributing to hair loss?
Noticing more shedding after starting treatment can raise concerns about the medicine. Yet the hair may still be responding to an earlier imbalance, because hair renewal does not change immediately. The timing needs to be reviewed with the prescriber, alongside blood results and other possible causes.
It would also be inaccurate to say that levothyroxine can never contribute to shedding. The current NHS page on the medicine lists hair loss among its possible side effects and explains that many side effects occur when the dose is too high. This warrants a medical discussion; it does not establish that the medicine is responsible for your own hair loss.
Do not stop levothyroxine to test this possibility. Explain what has changed, when it began and whether a prescription changed beforehand. Your clinician can check whether treatment remains appropriate, while a pharmacist can help identify problems with how you take it or interactions with other products.
Some supplements, including those containing iron or calcium, can interact with levothyroxine. Ask about compatibility and how to take them before adding a course of hair supplements. Being available without a prescription does not mean a product will have no effect on an existing thyroid treatment.
When might the hair start to recover?
Improvement is assessed over months rather than a few days. Reduced shedding and restored volume are different stages: new shafts still have to grow before contributing to coverage. Neither a single TSH result nor the date treatment began provides a reliable personal timetable for recovery.
The available evidence cannot promise a complete return to previous density. How long the problem has been present, how well it is controlled and whether another form of alopecia coexists all affect the interpretation of progress. If general health improves but thinning continues, the hair needs reassessment rather than assuming that the problem has been resolved.
A few photographs taken at intervals, with a similar parting, lighting and camera angle, may help describe changes during follow-up. They do not replace examination or measure thyroid activity. Report worsening loss, new bald patches or scalp symptoms instead of waiting for an arbitrary deadline for regrowth.
Meanwhile, adjust styling if the lengths are fragile, limiting pulling and handling that breaks the hair. A cosmetic product may improve comfort or appearance, but cannot correct an underactive or overactive thyroid. Before considering surgery for persistent thinning, the hair transplant guide can help you prepare questions once a diagnosis has been established.
Is there a place for a hair transplant after assessment?
Hair loss associated with a thyroid imbalance is not, by itself, an indication for transplantation. The priority is to establish the cause, manage the thyroid condition and review progress with medical follow-up. Surgery does not regulate hormones or replace that diagnostic work.
If a separate, lasting form of alopecia remains, a hair restoration assessment may be considered when your health allows. The diagnosis, progression and quality of the donor area matter to that decision. Our article about hair transplantation with a thyroid condition covers the questions specific to that situation, without setting one waiting period for everyone.
Assessment can begin with your usual doctor, without immediately arranging travel. If surgery later becomes appropriate, Body Expert offers support from an English-speaking coordinator to help prepare the journey. The information about a hair transplant in Istanbul then provides a basis for discussing practical arrangements with your medical situation already clarified.
Sources
Hussein, R. S., Atia, T., & Bin Dayel, S. (2023). Impact of thyroid dysfunction on hair disorders. Cureus, 15(8), e43266. https://doi.org/10.7759/cureus.43266
National Institute for Health and Care Excellence. (2023, October 12). Thyroid disease: assessment and management (NG145). NICE guideline, PDF
NHS. (2023, September 29). Hair transplant. https://www.nhs.uk/tests-and-treatments/cosmetic-procedures/cosmetic-surgery/hair-transplant/
NHS. (2026, July 6). Levothyroxine. https://www.nhs.uk/medicines/levothyroxine/
NHS. (2023, April 11). Overactive thyroid (hyperthyroidism). https://www.nhs.uk/conditions/overactive-thyroid-hyperthyroidism/
NHS. (2025, April 28). Underactive thyroid (hypothyroidism). https://www.nhs.uk/conditions/underactive-thyroid-hypothyroidism/