Why the Pattern of Hair Loss Differs Between Hashimoto’s Disease and Graves’ Disease — Dr. Moriwaki Organizes the Difference Between Hypothyroidism and Hyperthyroidism in What Happens to the Hair, Together with the Positioning of Stem Cell Conditioned Media2026.07.19
It is not unusual for a thyroid problem to be quietly hiding in the background of a woman’s chronic hair shedding. In particular, Hashimoto’s disease (hypothyroidism due to chronic thyroiditis) and Graves’ disease (hyperthyroidism) tend to be lumped together as “thyroid disease,” yet what is actually happening to the hair is entirely different. Without understanding that hypofunction and hyperfunction differ in the pattern, progression and recovery of hair loss, patients often become bewildered when endocrine treatment has begun and yet “for some reason the shedding alone will not stop.” Here Dr. Moriwaki organizes the relationship between thyroid dysfunction and hair medically, and then explains how hair regenerative medicine using stem cell conditioned media should be positioned.
Key Points of This Article
・In Hashimoto’s disease (hypothyroidism), telogen conversion in the hair cycle advances, and thin hair without body tends to increase overall.
・In Graves’ disease (hyperthyroidism), the hair cycle shortens, and a pattern in which hair falls out before it can grow to full length is seen.
・Loss of the outer third of the eyebrows has classically been known as a sign of hypothyroidism.
・Even after thyroid hormone normalizes, there is a lag of several months before the hair cycle re-synchronizes.
・When shedding continues even after thyroid values have settled with treatment, an approach to the scalp environment including stem cell conditioned media can become a treatment option.
What Happens to the Hair in Hashimoto’s Disease (Hypothyroidism)
Hashimoto’s disease is a condition in which autoantibodies (anti-TPO, anti-Tg) slowly destroy thyroid tissue and thyroid hormone (FT4) secretion declines. Its prevalence is high, particularly among middle-aged women in Japan, and it is a daily experience to find subclinical hypothyroidism in a patient whose chief complaint was hair shedding.
The Hair Cycle Tilts Toward the “Telogen” Phase
Thyroid hormone controls systemic metabolism and is also involved in hair matrix cell division and protein synthesis. When hormone levels are low, not only does the anagen (growth) phase shorten, but many follicles transition to telogen (resting) earlier than they normally would. As a result, more hairs are lost with every shampoo or brushing, and this spreads over the entire scalp as a “diffuse telogen effluvium” pattern.
Change in Texture — Thin, Dry, Lifeless
In hypothyroidism, the alignment of cuticles in each hair strand also becomes disordered, and dryness, frizz and loss of shine progress in parallel. Noticing that “the usual styling won’t hold” or “the range where the scalp shows through has widened” comes first as a change in hair quality rather than as a simple decrease in the number of hairs. Mistaking this stage for AGA and starting self-directed measures risks delaying treatment of the underlying thyroid problem.
Loss of the Outer Third of the Eyebrows Is a Classic Sign
The finding of thinning at the outer third of the eyebrow tail (the so-called “Queen Anne sign”) has long been described in textbooks as a physical sign of hypothyroidism. Its frequency is not necessarily high, but when it overlaps with changes in scalp hair, it becomes a cue to consider endocrine evaluation.
What Happens to the Hair in Graves’ Disease (Hyperthyroidism)
Graves’ disease is a condition in which TSH receptor antibodies excessively stimulate the thyroid, and hormone (FT4) is oversecreted. Palpitations, weight loss, and excessive sweating are well known, but thinning hair is in fact a common accompanying symptom.
“Compression” of the Hair Cycle Occurs
In contrast to hypothyroidism, in hyperthyroidism metabolism runs excessively fast, so follicles race through anagen and move on to the next cycle. Imagine each follicle’s “lifespan per cycle” being shortened; hair falls out before it can grow to full length, so overall volume comes to look thin.
Replacement by Fine, Limp Hair
Hair seen before treatment of hyperthyroidism can become fine, straightened, and lifeless. When drug-induced hair loss from antithyroid drugs (methimazole, propylthiouracil) is added, patients may feel that “the shedding worsened once treatment started,” but in most cases this is reversible.
Shedding Can Continue for a While Even After Remission
Even after thyroid hormone normalizes, hair shedding can continue for several months as the compressed hair cycle re-synchronizes. It is important not to become impatient looking at values alone and think “it should already be cured.”
Stem Cell Conditioned Media as an Option for Those Whose Shedding Continues After Thyroid Treatment
Even after thyroid function normalizes, shedding continuing for several months to about half a year is, as noted above, within the physiological range. However, when a sense of recovery is poor even six months after normalization, or when other factors such as AGA, FAGA, or iron deficiency overlap, adding an approach that reorders the scalp environment can create room to push the recovery curve forward. This is where hair regenerative treatment using stem cell conditioned media comes in.
The Layer It Works On and the Mechanism
Stem cell conditioned media is the supernatant (secretome) obtained when mesenchymal stem cells are cultured; it contains growth factors involved in the follicular microenvironment such as VEGF, IGF-1, HGF, and FGF, together with miRNAs carried by exosomes. It is not a treatment that transplants cells themselves, but is positioned as a signaling therapy that sends “signals in the direction of recovery” to the balance of blood flow, immunity, and fibrosis around the follicle.
The Order That Should Be Prioritized for Thyroid Patients
When proposing conditioned media treatment to a patient with thyroid disease, we make it an absolute prerequisite that “internal medical control is stable.” Treating only the scalp during a period when TSH and FT4 are fluctuating wildly does not suppress the background factors of shedding, so results are hard to accompany the effort — and this can lead to patient disappointment.
Consideration for Coexisting Autoimmune Diseases
Autoimmune thyroid disease can be accompanied by other autoimmune diseases such as alopecia areata, vitiligo, and rheumatoid arthritis. When alopecia areata coexists on the scalp, stem cell conditioned media is not a treatment that “cures” alopecia areata, so parallel work with dermatological treatment and a clear division of roles are required.
Order of Consultation and Testing — Where to Begin
Among patients presenting with hair shedding, when the interview and inspection raise suspicion of thyroid disease, we prioritize blood tests such as TSH, FT4, anti-TPO antibody, and anti-Tg antibody. In parallel we run nutritional assessment including ferritin, zinc, and vitamin D, and examine whether an AGA or FAGA pattern is overlapping. For differential diagnosis of alopecia, please also refer to the guidelines of the Japanese Dermatological Association.
The thyroid treatment itself is coordinated with internal medicine and endocrinology, while a realistic hybrid is to combine, on the scalp side, treatments such as stem cell conditioned media and topical therapies. For other hair-related themes, please see our hair regenerative medicine column index.
Frequently Asked Questions
Q. I started thyroid treatment but the shedding actually feels worse. Is this a failure?
In the first weeks after starting treatment for Graves’ disease, or after introducing levothyroxine for Hashimoto’s disease, shedding can transiently increase during the process of hair-cycle re-synchronization. In most cases it settles over 3–6 months. However, if you notice rapid worsening, scalp inflammation, or round patches of hair loss, please do not leave it and consult your attending physician.
Q. My thyroid values are normal but my thinning is progressing. Should I consider them unrelated?
Even when TSH is within the reference range, subclinical hypothyroidism or autoantibody-positive states can affect the hair cycle. Evaluation together with other factors — ferritin, vitamin D, and female hormones — is necessary.
Q. Can I receive scalp treatment with stem cell conditioned media even if I have thyroid disease?
If control of thyroid hormone is stable, it is not contraindicated. However, when treatment is still being adjusted or subjective symptoms are strong, we lower its priority and put internal medical control first.
Q. Only the outer part of my eyebrows has thinned. Will scalp care alone bring it back?
Loss of the outer eyebrow is known as a sign of hypothyroidism. Rather than eyebrow care first, we recommend checking thyroid, iron, and nutritional status with blood tests and giving priority to any needed internal medical treatment.
Q. Does stem cell conditioned media itself affect thyroid hormone?
At this point there is no established evidence that stem cell conditioned media alters thyroid hormone secretion or antibody titers. It is a treatment that acts on the scalp microenvironment, not a substitute for the treatment of the thyroid itself.
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【Medical Supervisor】Shin Moriwaki (Supervising Physician)
Member, Japan Society of Aesthetic Surgery (JSAS) / Member, American Academy of Aesthetic Medicine
ECFMG Certificate
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📍AVAN TOKYO Ginza Hair Regenerative Medicine
AVAN TOKYO Ginza Hair Regenerative Medicine
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