Can I have hair loss from iron deficiency if my haemoglobin is normal?

Yes, and this is the single most commonly missed cause. Haemoglobin measures the iron currently in your blood. Ferritin measures your stored iron. Stores empty first, so ferritin can be very low while haemoglobin is still normal and a CBC looks clean. Hair follicles are sensitive to stored iron, so shedding can begin long before anaemia appears.

How many hairs a day is normal to lose?

Roughly 50 to 100 hairs a day is normal. What matters more than counting is change: noticeably more hair in the comb, on the pillow or in the drain than a few months ago, or hair coming out in handfuls when washing.

Why did my hair start falling months after I was ill?

This is telogen effluvium. A shock such as fever, infection, surgery, childbirth, rapid weight loss or severe stress pushes many follicles into their resting phase at once. Those hairs stay in place for two to four months before they release, so the shedding appears well after the event that caused it. Count back two to four months from when shedding started to find the trigger.

Should I stop biotin supplements before a blood test?

Yes. High-dose biotin interferes with many common lab assays and can produce falsely abnormal thyroid results and falsely low troponin results. If you take a biotin or hair supplement, tell the lab and stop it for at least two to three days before testing, or the thyroid results may be misleading.

Which tests should I do first if money is tight?

Serum ferritin, a thyroid panel including TSH, and vitamin B12. Together these three catch a large majority of correctable causes and usually cost between about 1,200 and 1,600 rupees in India. Add vitamin D next if you can.

Sudden Hair Fall in Women: Causes and Diagnosis

Q: Will my hair grow back?

In most cases yes. Telogen effluvium and deficiency-related shedding are reversible once the cause is corrected, though it takes time: shedding usually slows within three to six months and density recovers over six to twelve months. Female pattern hair loss is different, being progressive rather than reversible, but it can usually be slowed or stabilised with treatment.

Q: Does onion juice stop hair fall?

The evidence is much weaker than the internet suggests. It rests largely on one small study from 2002 in alopecia areata, a different condition from the diffuse shedding most women have. It is unlikely to be harmful, but it will not correct low ferritin or an underactive thyroid, and it is not a substitute for finding the cause.

Q: Can heavy periods alone cause hair loss?

They can. Heavy or prolonged periods are one of the main routes to depleted iron stores in women, and the loss is gradual enough that haemoglobin often stays normal for a long time while ferritin falls. If your periods are heavy, ferritin is the test to insist on, and the bleeding itself is worth discussing with a doctor rather than accepting as normal.

What this page is. Educational information, so the right tests get ordered - not a diagnosis or a treatment plan. Hair loss is often the first visible sign of a thyroid or iron problem worth treating in its own right.

First, work out which problem you have

Almost every useful decision follows from this distinction, and it is the step most people skip.

Pattern A

Shedding, all over

More hair than usual coming out - in the comb, the drain, on the pillow. Handfuls when washing. Started fairly suddenly. Your parting looks the same width; the whole scalp has thinned a little.

Usually telogen effluvium. A reaction to something: a deficiency, an illness, a shock. Reversible once the cause is fixed.

Pattern B

Thinning at the parting

Not much extra hair falling. But the parting has widened over years, the crown shows more scalp, the ponytail is thinner. Gradual, not sudden.

Usually female pattern hair loss. Genetic and progressive. Treatable and can be stabilised, but not a deficiency to correct.

The rest of this page is about Pattern A - the kind that is usually correctable. Plenty of women have some of both.

The two-to-four month rule

Hair falls out two to four months after the thing that caused it. This single fact confuses almost everyone.

A shock pushes a batch of follicles into their resting phase all at once. Those hairs sit there for a couple of months, then release together. So do not ask what changed this month - ask what happened two to four months ago.

The gap is the whole problem: by the time hair falls, the cause is two to four months in the past - so it rarely feels connected to anything.

Causes, in the order they usually turn out to be

For sudden diffuse shedding with a normal CBC, roughly this order of probability.

Low iron stores (low ferritin)The most common, and the most missed, because a CBC can look perfectly normal. Especially likely with heavy periods, a mainly vegetarian diet, or any long-standing digestive problem.
Thyroid dysfunctionVery common in Indian women, particularly over 40. Both underactive and overactive thyroid cause diffuse shedding, and a mildly abnormal thyroid often has no other obvious symptoms.
Telogen effluvium after illness or shockFever, infection, surgery, hospitalisation, severe emotional stress. Settles on its own once the trigger has passed - but only if nothing else is also wrong.
Vitamin D deficiencyExtremely widespread in India, including in people who are outdoors a lot, and frequently in single figures with no symptoms at all.
Vitamin B12 deficiencyCommon on vegetarian and vegan diets, and in anyone on long-term acid-reducing medication or metformin. A CBC can be normal here too.
Rapid weight loss or low protein intakeHair is made of protein and is the first thing the body stops spending on. Crash dieting is a very common trigger - including healthy dieting done too fast.
Postpartum sheddingNear-universal, peaks around three to four months after delivery, and resolves on its own by six to twelve months.
PerimenopauseCan begin years before periods actually stop, so it is easy to dismiss if you are still menstruating normally.
MedicationBlood pressure drugs, some antidepressants, starting or stopping hormonal contraception, thyroid dose changes, regular NSAIDs and others.
Traction from hairstylesTight buns, braids and daily pulling. Often looks sudden when it finally reaches a tipping point, and shows most at the temples and hairline.

Why a normal CBC does not settle anything

A CBC measures the iron in your blood right now. It does not measure your iron stores.

Stores empty first. Haemoglobin can be a comfortable 12 while ferritin is 8 - the CBC reads clean, and the follicles have been running empty for months. A CBC also cannot see your thyroid, vitamin D, B12, zinc or hormones at all.

The ferritin number that matters

Lab reference ranges begin at about 12-15 ng/mL because they exist to catch anaemia. Hair needs more than the bare minimum. The exact target is still debated, but the practical point is not - a ferritin of 18 prints as normal and may still be the cause.

Reference ranges are set to catch anaemia, not to keep hair growing. Read the number, not the flag.

Not sure which of these apply to you? The hair fall check asks twelve questions about your symptoms, cycle and recent health, then ranks these tests for your situation and writes a summary you can hand your doctor. Free, and nothing leaves your browser.

The panel worth asking for

Test	Typical cost	Why it is on the list
Serum ferritin	₹400-700	Iron stores. Highest-yield single test, and invisible on a CBC
Thyroid panel TSH, free T4, free T3, anti-TPO	₹600-1,200	TSH alone can miss it. Anti-TPO catches autoimmune thyroid disease early
Vitamin B12	₹500-900	Vegetarian diets, acid-reducing medication, metformin
Vitamin D (25-OH)	₹500-900	Deficiency is the norm rather than the exception in India
Serum zinc	₹400-700	Causes shedding directly, and impairs thyroid function too
Folate	₹500-800	Worth adding on restricted diets or long-term acid suppression
Fasting glucose & HbA1c	₹400-700	Insulin resistance and PCOS-related shedding
Androgens & prolactin testosterone, DHEA-S, prolactin	₹1,200-2,000	Only if there are PCOS signs: irregular periods, acne, facial hair

Indicative Indian private-lab prices, 2026. They vary considerably by city and lab, and bundled packages are often cheaper than individual tests. Most national labs offer home sample collection.

If the budget is tight, do these three: ferritin, thyroid, B12. Around ₹1,200-1,600 together, and between them they account for the large majority of correctable causes. Add vitamin D next. Leave the hormone panel unless there are PCOS signs.

One thing to do before the blood draw

Stop biotin and hair-growth supplements two to three days beforehand. High-dose biotin interferes with many lab assays. It can make thyroid results look abnormal when they are fine, or normal when they are not, and it can falsely lower troponin - the heart-attack test. Tell the lab what you have been taking. This is a genuinely common cause of misleading thyroid results and almost nobody mentions it.

Questions that often find the answer first

Work backwards from the month the shedding began.

Fever, infection, dengue, typhoid or COVID two to four months before it started?
Surgery, a hospital stay or childbirth in that window?
Dieting or weight loss - how fast, and did protein drop?
Periods heavier or more irregular? Heavier means more iron lost.
Any new or newly stopped medication, including contraception and thyroid tablets?
Long-term acid-reducing tablets? Years on a PPI reduce absorption of B12, iron and magnesium. Test rather than assume.

While you wait for results

Worth doing

Iron-rich food with vitamin C. Dates, jaggery, beetroot, greens; liver or red meat if you eat them. Lemon or amla alongside.
No tea or coffee within an hour of meals. Tannins block iron absorption substantially.
Protein at every meal. Hair is keratin. Dal, curd, paneer, eggs, soy, nuts.
Handle hair gently. Loose styles, wide-tooth comb, no hard brushing when wet.
Expect to wait. Shedding takes weeks to slow even once the cause is fixed.

Not worth it

Oils, serums and shampoos. Nothing on the scalp corrects low ferritin or a thyroid problem. That money buys the whole panel.
Minoxidil before a diagnosis. It increases shedding when you start, which is indistinguishable from getting worse.
Untested high-dose supplements. Iron without a ferritin result can harm; excess zinc and selenium cause their own problems.
Hair clinics before blood work. Many sell PRP and analysis packages before anyone orders a ferritin test. See a dermatologist.
Waiting it out. Post-illness shedding settles by itself. Thyroid disease and iron depletion do not.

See a doctor promptly if

Most shedding is not urgent. These signs are different, because a few conditions destroy follicles permanently and the window to prevent that is short.

Smooth round bald patches rather than general thinning. A scalp that is painful, burning, itchy, scaly, red or scarred, or areas where the skin looks shiny and the follicle openings have disappeared. Hair loss alongside other symptoms - joint pain, rashes, a lot of new facial hair, a deepening voice, very irregular periods.

Diffuse shedding that keeps going beyond six to nine months also deserves a proper dermatology assessment rather than another round of supplements.

The realistic timeline

Once the cause is corrected, shedding slows over three to six months and density recovers over six to twelve. Nothing meaningful happens in two weeks, whatever the product promises.

The reassuring part: unlike male pattern baldness, most sudden shedding in women is a correctable deficiency or a temporary reaction. Find the cause and the hair generally comes back.

Common questions

Can I have iron-related hair loss if my haemoglobin is normal?

Yes - this is the most commonly missed cause of all. Haemoglobin shows the iron in circulation; ferritin shows the iron in storage. Stores run down first, so ferritin can be very low while haemoglobin is still normal and the CBC looks clean. Hair follicles are sensitive to stored iron, so shedding often begins well before anaemia appears.

How many hairs a day is normal?

Roughly 50 to 100. But counting matters less than comparing: noticeably more hair in the comb, drain or pillow than a few months ago is the real signal, as is hair coming away in handfuls when you wash.

Why did the shedding start months after I was ill?

Because that is how telogen effluvium works. The shock pushes many follicles into their resting phase at once, and those hairs stay in place for two to four months before releasing together. The delay is exactly why the cause gets missed - you feel completely recovered by the time the hair starts falling.

Will my hair grow back?

Usually, yes. Telogen effluvium and deficiency-driven shedding are reversible once the cause is corrected, over six to twelve months. Female pattern hair loss behaves differently - it is progressive rather than reversible - but it can generally be slowed or held stable with proper treatment. Which is a further reason to establish which one you have.

Should I stop biotin before blood tests?

Yes, for two to three days, and tell the lab you have been taking it. High-dose biotin interferes with a range of common assays, most importantly thyroid tests, and can also falsely lower troponin. It is a well-documented cause of misleading results and rarely mentioned.

Does onion juice work?

Far less convincingly than the internet suggests. The evidence traces largely to one small 2002 study in alopecia areata - a different condition from the diffuse shedding most women have. It is unlikely to hurt, but it cannot correct low ferritin or a thyroid problem, and time spent on it is time not spent finding the cause.

Which tests first, if I can only afford a few?

Serum ferritin, a thyroid panel including TSH, and vitamin B12 - roughly ₹1,200 to ₹1,600 together, and between them they explain most correctable cases. Vitamin D next. Leave the hormone panel unless there are PCOS signs such as irregular periods, acne or new facial hair.

Is heavy bleeding enough on its own to cause this?

It can be. Heavy or prolonged periods are one of the main routes to depleted iron stores in women, and the drain is gradual enough that haemoglobin often stays normal for a long time while ferritin falls. If your periods are heavy, ferritin is the test to insist on - and the bleeding itself is worth discussing with a doctor rather than accepting as normal.

Tracking your cycle may help the conversation. If heavy or irregular periods might be part of the picture, a few months of dates make the pattern much clearer to a doctor. Our period tracker works out your real average cycle and how regular you actually are, entirely in your browser.