Ferritin measures your iron stores — and it is one of the most important biomarkers for hair health. The problem: a ferritin level that falls within your lab’s “normal” reference range may not be high enough to support healthy hair growth. This gap between what your blood test calls normal and what your hair actually needs is the space where most unexplained shedding lives.
Your bloods came back normal. But your hair is still shedding.
If you have heard that sentence — from your GP, from yourself, from the results printed on a page — you are not imagining the problem. You are experiencing the most common blind spot in hair-loss investigation: the difference between a ferritin level that keeps you out of clinical anaemia and a ferritin level that keeps your hair in its growth phase.
This is not a fringe theory. The connection between ferritin and hair loss is one of the most consistent patterns in trichology practice. And understanding how blood tests for hair loss actually work — and where they stop — is the first step toward an answer that matches what you see in the mirror.
What ferritin is and why it matters for hair
Ferritin is a protein that stores iron in your cells. Think of it as a warehouse: haemoglobin is the delivery truck that carries oxygen through your blood right now, and ferritin is the stockpile that tells you how much iron your body has in reserve.
When your body needs iron — for oxygen transport, enzyme function, cellular energy — it draws from that stockpile. And here is the detail that matters for your hair: the body prioritises vital organs first. Heart, brain, muscles. Hair follicles, as non-essential tissue, are at the back of the queue.
So when iron stores start to fall, your hair feels it before you do. Long before your ferritin drops low enough to trigger anaemia on a blood test, it may have already dropped below the level your follicles need to maintain a healthy growth cycle. The warehouse is not empty — but the hair department has already stopped receiving deliveries.
The "normal" vs "optimal" gap — and why it matters for ferritin and hair loss
Standard UK laboratory reference ranges for ferritin in women typically start from around 11–15 μg/L at the lower end. In Ireland, the range is similar. If your result comes back at 18, or 25, or even 35 — your GP sees a number inside the normal range and, quite reasonably, tells you nothing is wrong.
They are right, from their clinical perspective. A ferritin of 25 does not indicate iron-deficiency anaemia. You do not need an urgent haematology referral. The system designed to flag disease has done its job.
But your hair does not care about reference ranges. Your hair cares about supply.
Published research paints a more nuanced picture than the lab printout suggests. Kantor et al. (2003) found that women with androgenetic alopecia had a mean ferritin of 37.3 ng/mL — statistically significantly lower than the 59.5 ng/mL seen in women without hair loss. Park et al. (2013) used a threshold of 70 μg/L to identify iron-depleted individuals and found that 80% of women with female pattern hair loss fell below that line, compared with fewer than 20% of controls.
Nutritional research by Rushton (2002) proposed that ferritin levels above 70 μg/L — and ideally between 100 and 150 μg/L — were needed for meaningful improvements in hair shedding rates. That is a very different number from the 11–15 that sits at the bottom of a standard lab range.
And here is the honest caveat: not all studies agree. Bregy and Trüeb (2008) found no association between ferritin levels above 10 μg/L and hair loss activity in a cohort of 181 women, concluding that iron’s role may be overestimated in some cases. The evidence is not settled. There is no single, universally agreed optimal ferritin level for hair.
This is one of the most consistent patterns in my practice. A client comes in distressed — she has been shedding for months, sometimes years. She has already seen her GP. The bloods came back normal. She has been told there is nothing wrong. And her ferritin is sitting at 22, or 28, or 34.
In my clinical experience, I like to see ferritin well above 30 ng/mL — and in practice, I find that clients with levels in the higher ranges tend to respond better. But I want to be clear: this is my clinical preference based on what I see in my consulting room, not a universally agreed medical threshold. Different trichologists and dermatologists have different views, and the published literature reflects that range of opinion. What I can tell you is that the gap between “not anaemic” and “hair-healthy” is real, and it is where most of the frustration lives.
The question is not “is my ferritin normal?” The question is “is my ferritin high enough for my hair?” Those are two different questions — and they can have two different answers.
Why your GP might not flag low-normal ferritin and hair loss
This is not a criticism of GPs. It is a structural observation about two different systems asking different questions of the same blood test.
Your GP screens for disease. When they request a full blood count and an iron panel, they are looking for clinical pathology — anaemia, iron-deficiency anaemia, haemochromatosis. The reference range on your results reflects that clinical frame: “is this person ill?” If the answer is no, the system does what it is designed to do and moves on.
A trichologist reads the same results and asks a different question: “is this person’s iron supply adequate for non-essential tissue — specifically, for hair follicles that are already competing with more critical organs for the same nutrient?” That is a narrower question, aimed at a tissue that gets deprioritised early. The same blood test. Different lens.
This is why the relationship between your GP and your trichologist matters. They are not in conflict — they are looking at the same data from different distances. Your GP rules out the serious causes. Your trichologist reads the subtler patterns in what remains. The best outcomes happen when both are involved.
What to do about low-normal ferritin
If your ferritin is technically normal but sitting at the lower end of the range — and your hair is shedding — there are practical steps. But they all start in the same place: with your GP.
Start with a conversation, not a supplement. Iron is one of the few nutrients where more is not automatically better. Excess iron can cause serious harm — it accumulates in organs, and conditions like haemochromatosis (iron overload) can damage the liver, heart, and pancreas. Never self-prescribe iron supplements without medical guidance.
Get the right tests. Ferritin alone does not give the full picture. A complete iron panel — serum iron, transferrin saturation, total iron-binding capacity (TIBC) — alongside a full blood count gives both your GP and your trichologist the context they need. And one important caveat: ferritin is an acute-phase reactant, which means it can be artificially elevated by inflammation, infection, or liver conditions. A “normal” ferritin reading in someone with active inflammation may actually mask underlying iron depletion.
Dietary iron sources matter. Haem iron (from red meat, liver, shellfish) is absorbed significantly more efficiently than non-haem iron (from spinach, lentils, fortified cereals). If you eat a plant-based diet, pair iron-rich foods with vitamin C to improve absorption, and be aware that tea, coffee, and calcium can inhibit uptake when consumed at the same meal.
Timelines are slow. Even with effective supplementation (supervised by your GP), ferritin levels take time to rebuild. Most practitioners advise retesting at three-month intervals. And because of the hair growth cycle, it can take six to twelve months from the point your ferritin reaches a healthier level before you see meaningful improvement in shedding or density. This is not a quick fix — it is a slow, evidence-led correction.
When ferritin is not the only factor
Ferritin is important. But it is rarely the only thing going on.
In clinic, most hair shedding turns out to be multi-cause. A client might present with low-normal ferritin and suboptimal vitamin D, and a thyroid reading that is technically within range but sitting at the edge. Or low-normal ferritin compounding a telogen effluvium triggered by stress or illness six months ago. Or ferritin depletion layered on top of early-stage androgenetic alopecia, where the genetic component is already at work and the nutritional shortfall is making it worse.
This is why isolated blood tests rarely give the full answer. The value of a trichological assessment is in reading the combination — seeing how ferritin interacts with the rest of your biomarker profile, your scalp health, your clinical history, and the pattern of loss under trichoscopy. Ferritin is one thread in a larger picture, and treating it in isolation sometimes helps, but almost never resolves the whole problem.
Has your GP told you your bloods are normal — but your hair is still shedding?
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Frequently asked questions about ferritin and hair loss
There is no single universally agreed number, which is part of the problem. Standard lab ranges flag ferritin below 11–15 μg/L as low in women, but published research suggests levels below 70 μg/L may already be affecting hair. Some trichologists and dermatologists target even higher. In my practice, I like to see ferritin well above 30 ng/mL, and I find the higher it sits within a healthy range, the better the hair tends to respond. Discuss your individual target with both your GP and your trichologist.
Yes. Ferritin measures your iron stores, not the iron circulating in your blood right now. It is possible for serum iron to be within range while your stored reserves are quietly running down. Hair follicles depend on those reserves for sustained function — and because hair is non-essential tissue, it loses supply before vital organs do. A technically “normal” ferritin can still mean your follicles are under-supplied.
With appropriate supplementation (prescribed and supervised by your GP), most people see ferritin levels begin to rise within two to three months. But rebuilding depleted stores fully can take six months or longer, depending on how low you started, how well you absorb the supplement, and whether the underlying cause of depletion (heavy periods, diet, gut absorption issues) has been addressed. Hair improvement lags further behind — typically six to twelve months after ferritin reaches a healthier level.
Only with medical guidance. Iron is not a nutrient you should self-prescribe. Excess iron accumulates in the body and can cause serious organ damage — including liver, heart, and pancreatic harm. Your GP can test your iron panel, determine whether supplementation is appropriate, choose the right form and dose, and monitor your response. Never take iron supplements because a website suggested it.
Yes — and this is not a minor risk. Iron overload (haemochromatosis) can damage the liver, heart, joints, and pancreas. It can be genetic (hereditary haemochromatosis, which is relatively common in Irish and Northern European populations) or acquired through excessive supplementation over time. This is exactly why iron supplementation should always be supervised by your GP, with regular blood monitoring.
Ferritin is one piece of a broader picture. A comprehensive hair-health blood panel typically includes a full blood count, serum iron, transferrin saturation, TIBC, vitamin D, vitamin B12, folate, thyroid function (TSH, free T4, free T3), and hormonal markers where relevant. Each can contribute to shedding independently — and in combination, they often explain patterns that no single test could. We cover the full panel in our guide to blood tests for hair loss.
Because your GP and your trichologist read the same blood test with different questions in mind. Your GP screens for disease — anaemia, pathology, conditions requiring treatment. If your ferritin is above the deficiency threshold, the system rightly flags it as normal. A trichologist asks a narrower question: is the level adequate for hair follicle function? Neither is wrong; they are looking at the same data through different lenses. The most effective approach is a conversation between both — your GP managing your medical care, your trichologist interpreting the subtler patterns in the context of your hair specifically.
Key takeaways
Ferritin measures iron stores, not circulating iron. It tells you how much your body has in reserve — and hair follicles draw from that reserve as non-essential tissue, after vital organs have been served first.
“Normal” ferritin is not always “optimal” for hair. Standard UK lab ranges start as low as 11–15 μg/L for women, but published research and clinical experience suggest hair may need significantly more. The gap between not-anaemic and hair-healthy is where most unexplained shedding lives.
The evidence is real but not settled. Multiple studies link lower ferritin to hair loss in women, but not all agree on thresholds or mechanisms. This is clinical judgment, not textbook consensus — and honest practitioners will tell you that.
Never self-prescribe iron. Excess iron causes serious harm. Supplementation should always be supervised by your GP, with regular monitoring. Dietary sources and absorption optimisation come first.
Ferritin is one thread, not the whole picture. Most hair shedding is multi-cause. The value of a trichological assessment is reading ferritin alongside the rest of your biomarker profile, your scalp, and your clinical history.
Hair Health Essentials was founded by Clare Devereux, one of Ireland and the UK’s leading IAT-certified clinical trichologists. We combine trichoscopy, blood biomarker analysis, and personalised treatment protocols with naturally formulated, COSMOS-certified products — because your hair deserves both the science and the care. Harley Street, London. Clinics also in Dublin.
This article is for information purposes and doesn’t replace medical advice. Please discuss any medication concerns with your prescribing doctor.
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IAT-Certified Clinical Trichologist
Clare Devereux
Clare is the founding clinical trichologist at Hair Health Essentials, practising in Dublin and London. With over a decade of clinical trichology experience underpinned by a lifetime in professional hair and scalp care, she specialises in personalised diagnostics — from trichoscopy and blood biomarker analysis to genetic testing — to identify what’s really happening with your hair and scalp.
Clinics: Blackrock, Dublin · Eden One, Dublin · Harley Street, London
Hair Health Essentials provides specialist trichological guidance. This content is for informational purposes and does not constitute medical advice. If you have concerns about your health, please consult your GP or medical practitioner.
With naturally formulated, COSMOS-certified products
— because your hair deserves both the science and the care.