At Opti Laboratories, we have helped many clients experiencing eyelash and eyebrow thinning connected to thyroid disorders whether due to the condition itself or the medication used to treat it. The thyroid gland plays a pivotal role in hair growth cycles, and both hypothyroidism and hyperthyroidism (especially when autoimmune in origin) can bring changes to the lashes and brows. With our clinical background and aesthetic focus, we are uniquely positioned to guide you with compassionate, evidence-based support.
Hair (including lashes and brows) grows in three phases:
Anagen (growth phase) — follicles actively produce hair.
Catagen (transition phase) — growth slows and follicle begins to regress.
Telogen (resting/shedding phase) — hair sheds before new growth resumes.
Thyroid hormones (T3 and T4) help regulate the duration of these cycles, especially the anagen phase. When hormone levels are too low (hypothyroidism) or too high (hyperthyroidism), follicles can prematurely enter telogen, causing diffuse shedding — often including the eyelashes and the outer third of the eyebrows.
Autoimmune thyroid diseases can affect lash and brow health both directly and indirectly:
Hashimoto’s Thyroiditis (the most common cause of hypothyroidism in women): Immune-mediated damage leads to low thyroid hormone levels and can result in diffuse hair thinning and loss, including the classic outer third of the eyebrows which is known as Hertoghe’s sign or Queen Anne’s sign.
Graves’ Disease (an autoimmune form of hyperthyroidism): Excess thyroid hormone can disrupt hair cycling, leading to eyelash and eyebrow thinning. In some patients, coexisting autoimmune alopecia areata may cause patchy lash or brow loss.
Carbimazole and Propylthiouracil
These are used to treat hyperthyroidism by reducing the rate of thyroid hormone synthesis. It can lead to temporary hair shedding when first used, including of the lashes and brows, but most find that it happens only during the early months of treatment.
Levothyroxine (T4) and Liothyronine (T3)
These are used to replace the hormones that are lacking in hypothyroidism. They take time to work so shedding can continue if doses are not yet balanced at the optimal level. In many cases, once stabilised, these medicines support regrowth.
Beta-blockers like propranolol or atenolol
Often prescribed in Graves’ disease to control symptoms like tremor or palpitations while thyroid levels are stabilised. Beta-blockers themselves can trigger telogen effluvium, sometimes affecting lashes and brows.
Is the lash or brow loss permanent?
In most cases, no it is not. Most people find that once thyroid levels stabilise the follicles often recover although regrowth may take several months.
Why are my lashes or brows still falling out even when my levels are normal?
Hair cycles can lag behind hormonal correction by at least a few months. There is not always a direct correlation between thyroid levels and the symptoms experienced.
What does eyebrow thinning in thyroid disease typically look like?
Hypothyroidism often causes thinning of the outer third of the eyebrows. This is a well-known sign of thyroid imbalance.
Should I stop or change my thyroid medication to protect my lashes and brows?
Absolutely not. Thyroid medication is essential for your health. Always consult your doctor before making any changes.
Do thyroid medications cause hair loss?
Sometimes, yes. Anti-thyroid drugs such as carbimazole and PTU can trigger temporary shedding in the early stages. Beta-blockers (often prescribed alongside them) can also cause telogen effluvium. Even levothyroxine or liothyronine can be linked to shedding if the dose is not well balanced. Importantly, in most cases, hair regrows once levels are stabilised.
How can I support regrowth?
Ensure stable thyroid hormone control.
Maintain good nutrition (iron, vitamin D, selenium, biotin).
Consider bimatoprost 0.03% for stimulating lash and brow regrowth once thyroid levels are balanced.
Enhance regrowth with a serum that provides UV protection.
What it can do:
Accelerate regrowth after hormone levels are stabilised.
Improve lash and brow thickness, length, and pigmentation.
What it cannot do:
Cure autoimmune thyroid disease.
Reverse follicle loss directly caused by autoimmune conditions such as alopecia areata.
Replace the need for stable thyroid control — which remains the foundation of recovery.
Even with regrowth, some clients notice changes. Lashes may come back straighter or finer; brows may regrow lighter or sparser.
One of our clients was diagnosed her with hypothyroidism and prescribed thyroxine. Her eyelashes recovered well; however, she was able to achieve full regrowth with bimatoprost.
Eyelash and eyebrow loss due to thyroid disease or its treatments can be unsettling, but it is usually temporary and manageable. The key message is this: never stop or alter your thyroid medication without medical advice. Once hormone levels are stable, regrowth is highly likely — and supportive treatments can help speed and enhance the process.
At Opti Laboratories, we combine medical expertise with a focus on lash and brow recovery. If you are experiencing thyroid-related eyelash or eyebrow loss, please get in touch — we are here to help restore both your lashes and your confidence.
