Hair fall blood tests: what doctors usually check

Losing 50–100 strands a day is normal, but clumps on the pillow, a widening parting or thinning over months can point to something inside the body. Low iron stores, thyroid problems and vitamin deficiencies are among the common reasons, and they show up in blood tests. Checking them first helps your doctor or dermatologist plan the right next step.

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Tests to ask about

Thyroid profile (T3, T4, TSH)

Both low and high thyroid are well-known causes of hair thinning.

₹1,200 Book Details

Ferritin / Iron profile

Low iron stores are one of the most common findings in women with hair fall.

₹250 Book Details

Vitamin D (25-OH)

Low vitamin D is often seen in people with hair fall.

₹1,300 Book Details

Vitamin B12

B12 deficiency is common in vegetarians and may add to hair and skin problems.

₹1,090 Book Details

Complete blood count (CBC)

Checks for anaemia, which can weaken hair growth.

₹330 Book Details

Common reasons doctors look for

Low iron stores (low ferritin), especially in women
Thyroid imbalance – both low and high thyroid
Low vitamin D or vitamin B12
Hormonal changes such as PCOD in women
Hair fall 2–3 months after a fever, illness, surgery or delivery
Stress, crash dieting or low protein intake

How to prepare

Most hair fall tests (thyroid, ferritin, vitamin D, B12, CBC) do not need fasting. For hormone tests in women, your doctor may ask you to give the sample on a particular day of your cycle.

When to see a doctor

See a doctor or dermatologist if hair falls out in round patches, if there is scalp redness, pain or pus, or if hair loss comes with irregular periods, new facial hair or sudden weight change. Sudden heavy hair fall in a child should also be checked.

Hair Fall – FAQs

Which blood test is done for hair fall?

Commonly checked are thyroid profile, ferritin or iron profile, vitamin D, vitamin B12 and CBC. Women with irregular periods may also be advised hormone tests.

Can thyroid cause hair fall?

Yes, both underactive and overactive thyroid are known causes of diffuse hair thinning. A thyroid profile can show if this is a factor.

Why is ferritin checked even if haemoglobin is normal?

Ferritin shows your iron stores. It can be low before haemoglobin drops, and low stores are commonly linked with hair shedding.

Is fasting required?

Usually not for hair fall tests. Fasting is needed only if your package also includes fasting sugar or a lipid profile.

This page is general information, not medical advice or a diagnosis. Please talk to a doctor about your symptoms.