Blood Tests for Hair Loss in Australia

What blood tests can and cannot tell you about hair loss

Blood tests identify systemic and nutritional contributors to hair loss; they cannot diagnose androgenetic alopecia, alopecia areata or scarring alopecias, which are diagnosed clinically.

This distinction saves people money and disappointment. Male and female pattern hair loss is diagnosed by looking: the distribution of thinning, the presence of miniaturised hairs, the frontal hairline in men, the widened central part in women, and the history. No blood test confirms or excludes it.

What bloods do well is find the things sitting on top of that. A person with mild pattern loss and a ferritin of 12 µg/L is shedding for two reasons, one of which is correctable. Someone with sudden diffuse shedding three months after a fever, a crash diet or childbirth has telogen effluvium, and bloods rule out the coexisting problems rather than explaining the shedding itself.

The timing point is worth understanding. Hair follicles cycle: a stressor pushes follicles from growth into rest, and the hairs fall out roughly two to four months later. That means the blood test you take on the day the shedding starts reflects a body that has often already recovered from the event that caused it. A normal panel does not mean nothing happened.

Which blood tests are worth running

An Australian hair-loss work-up starts with ferritin and iron studies, thyroid function and a full blood count, and adds androgens, vitamin D and zinc depending on the pattern, sex and history.

Iron deficiency and hair loss

Ferritin is the most frequently abnormal result in people investigated for hair loss, and iron deficiency reduces hair growth well before haemoglobin falls.

Hair follicle matrix cells are among the most rapidly dividing cells in the body, and they compete poorly for iron when supply is limited. The body triages: haemoglobin production is protected, and non-essential functions including hair growth are throttled first. That is why you can have a completely normal full blood count, a normal haemoglobin, and still be shedding because of iron deficiency.

Ferritin is the storage marker and the one that matters here. A ferritin below 30 µg/L indicates iron deficiency by Australian criteria. In the hair-loss literature many dermatologists prefer a threshold above 50 µg/L before concluding iron is not a contributor, though this higher target is a clinical convention rather than a settled reference limit — it is worth knowing that the evidence base for it is debated.

One trap: ferritin is an acute phase reactant, so infection, inflammation, liver disease, obesity and recent alcohol all raise it. A ferritin of 60 µg/L in someone with active inflammation can conceal genuine deficiency, which is why transferrin saturation is measured alongside — a saturation below about 16% supports deficiency regardless of ferritin.

Iron deficiency also has a cause, and finding it matters more than correcting the number. In menstruating women, heavy periods are the usual explanation. In men and post-menopausal women, iron deficiency warrants investigation of gastrointestinal blood loss and coeliac disease — this is a genuine safety point, not a footnote.

The individual tests in a hair-loss work-up

Each component has its own reference guide covering Australian ranges and what moves the result.

• Iron studies and ferritin — the highest-yield test in hair loss — ranges, and why ferritin can be falsely normal.
• Thyroid function test — TSH and free T4, and why biotin can make both wildly misleading.
• Full blood count — anaemia and the context that makes a ferritin interpretable.
• DHT test — what DHT is, and the honest limits of what a serum level tells you about hair.
• Testosterone test — with SHBG and free androgen index, where hyperandrogenism is suspected.
• Vitamin D test — commonly deficient in Australia and often included in a hair-loss panel.
• Zinc test — relevant with restricted diets, malabsorption or bariatric surgery.
• Build your own Australian panel — assemble ferritin, thyroid and androgens in a single collection.
• FORM Australian panels — the standard tiers already include iron studies, thyroid and a full blood count.

Thyroid disease and hair loss

Both underactive and overactive thyroid cause diffuse hair thinning, and thyroid disease is common enough in Australia to justify testing everyone with unexplained shedding.

Thyroid hormone regulates the duration of the hair growth phase. Hypothyroidism shortens it and produces coarse, dry, diffusely thinning hair, sometimes with loss of the outer third of the eyebrows. Hyperthyroidism produces fine, soft hair with diffuse thinning. Both are reversible with treatment of the underlying thyroid problem, though hair recovery lags biochemical recovery by months.

Autoimmune thyroid disease also travels with alopecia areata — the patchy, well-circumscribed type — so thyroid antibodies are sometimes added when that pattern is present.

TSH with free T4 is the appropriate first-line pair. TSH alone is adequate screening in most contexts but adding free T4 avoids missing central hypothyroidism and helps interpret a borderline TSH.

What can distort a hair-loss blood panel

Supplements, recent illness and timing all move these markers, and biotin in particular can produce spectacularly wrong thyroid results.

• High-dose biotin — the defining ingredient of most hair, skin and nail supplements — interferes with immunoassays and can make TSH look suppressed and free T4 high, mimicking hyperthyroidism. Stop it 48–72 hours before testing. This matters more here than on almost any other panel, because the people being tested are the people taking it.
• Iron supplements taken in the days before the test raise serum iron and transferrin saturation without changing stores; ferritin is the more stable marker.
• Any infection or inflammation in the preceding two weeks raises ferritin and can mask deficiency.
• Recent illness, surgery, childbirth, rapid weight loss or severe stress cause telogen effluvium two to four months later — by the time hair falls, bloods have often normalised.
• Androgens vary through the day and, in women, through the cycle: collect in the morning, and on day 2–5 where cycle timing is relevant.
• Hormonal contraception raises SHBG and lowers free androgen index, which can mask biochemical hyperandrogenism.
• Very low-energy or restrictive diets reduce zinc, ferritin and protein availability simultaneously.

Who should consider a hair loss blood panel

Testing is most useful where shedding is diffuse, recent, rapid, or accompanied by other symptoms — and least useful where the pattern is classic and stable.

• Sudden or heavy diffuse shedding, particularly two to four months after an illness, pregnancy, surgery or major weight change.
• Hair loss with fatigue, cold intolerance, heavy periods, restless legs or pica — all suggestive of iron or thyroid problems.
• Female pattern hair loss with acne, hirsutism or irregular cycles, where androgens and PCOS are worth assessing.
• Vegetarian, vegan or restricted diets, coeliac disease, inflammatory bowel disease or previous bariatric surgery.
• Hair loss in men or post-menopausal women found to be iron deficient — the deficiency itself needs a cause.
• Before starting any medical management, so a coexisting deficiency is not left uncorrected.

How hair-loss testing works with FORM in Australia

You order the panel, we issue an Australian pathology request form, and you attend an accredited collection centre — ideally in the morning if androgens are included.

• No referral from your own GP is required. Privately requested pathology is arranged under a request from a registered medical practitioner working with our accredited lab partner.
• Collection is a walk-in at Laverty (Healius) pathology centres Australia-wide (NATA / ISO 15189 accredited).
• Results are returned in Australian SI units with a written, plain-English explanation.
• FORM is a diagnostic testing service. We do not prescribe or supply any treatment for hair loss — take your results to your GP or a dermatologist.
• Australian ordering is currently pre-sale. Join the waitlist and we will email you when ordering opens.
• Stop biotin-containing hair and nail supplements 48–72 hours before collection, and tell us if you cannot.
• Results typically report within one to three business days, with each marker explained in context rather than flagged as a bare high or low.
• Where an abnormal ferritin is found in a man or a post-menopausal woman, we will say clearly that the cause needs investigating with your GP rather than simply supplementing.