Feeling Exhausted? The Low-Iron Signs Women Often Miss—and the Tests to Ask For

In the ever-expanding list of things we're told to worry about, congratulations to us: we have another. ‘Ferritin face’ is the latest health trend sending women down a rabbit hole, questioning whether their dark circles, thinning hair and permanently knackered appearances could be signs of low iron. UK interest in the phrase reportedly surged 5,000% in a single week last month, according to Google Trends and TikTok data cited in reports. Five thousand per cent. We’re clearly hungry for answers—even if we’re not entirely sure what the questions are. And while ‘ferritin face’ might sound like another reason to inspect ourselves under unforgiving bathroom lighting, low iron is more than a beauty concern.

And while I'm not thrilled about having yet another thing to scrutinise under unforgiving bathroom lighting, I am pleased that ferritin is finally getting the attention it deserves. Iron deficiency is one of the most overlooked women's health issues, with symptoms too often brushed off and low iron stores (which is where ferritin comes into play) affecting us even before anaemia develops. If this trend is encouraging more women to ask questions, request tests and push for answers, I'm all for it. Even if we're not entirely sure what we're asking yet. The fact of the matter is: we deserve to understand our bodies, not simply learn to live with feeling rubbish.

There's really only so much Googling a woman can do, so in the name of womanhood, I've done the groundwork. I spoke to experts to unpack what ferritin actually is, which symptoms are worth paying attention to, what your blood tests can—and can't—tell you, and how to get the right support. Because, excuse the intrusive thought, but I can't help wondering how many women are walking around feeling rubbish simply because nobody's explained what their blood tests actually mean.

5 Subtle Low-Iron Signs in Women, Plus the Tests to Ask For

First, What Is Ferritin, How Is It Linked to Iron Deficiency, and Why Does It Matter?

Right, let’s dive in, because I know the woman on the other side of this screen is chomping at the bit to get to the bottom of what ferritin actually is.

First, a quick distinction: iron is the mineral your body needs to function; ferritin is the protein that stores it. “Measuring ferritin in your blood indicates how much iron you have in reserve. When those reserves run low, you can develop iron deficiency, even before you become anaemic,” says Professor Toby Richards of The Iron Clinic.

And iron matters for far more than making red blood cells: “your cells need it to produce energy, your brain needs it to make neurotransmitters such as dopamine and serotonin, which affect mood and concentration, and it is needed for normal thyroid hormone production,” explains women’s health GP Dr Faye Bate.

But what counts as low? Richards points to the World Health Organisation’s traditional threshold for iron deficiency: ferritin below 15 micrograms per litre. NICE guidance, updated in August 2024, uses below 30 as an indicator of iron deficiency, while newer 2026 guidance from the American Society of Haematology also used 30, with a threshold of 50 considered for some higher-risk groups, including women with heavy periods.

Why do these numbers matter? “Think of your ferritin as your body’s iron savings account. Your bone marrow needs iron to make red blood cells, but your body can dip into those reserves to keep production ticking along even as they dwindle. That means your ferritin can fall before your haemoglobin does—and before you meet the criteria for anaemia.” As Richards explains, you can be iron deficient without being anaemic. A haemoglobin result within the normal range, then, doesn’t necessarily mean your iron stores are in good shape.

Which leads me to our next collective question: why can women have low iron stores even when their haemoglobin levels appear normal? In short: “Your body uses up its iron reserves to keep haemoglobin stable for as long as it can,” explains Bate. “So ferritin can drop before haemoglobin does.” And because a standard full blood count from your GP doesn’t automatically measure ferritin, you can be told your bloods are normal without anyone having checked your iron stores. TDLR: low ferritin can mean iron deficiency, even if you’re not anaemic.

The symptoms of low iron every woman should know

Fatigue might be the obvious one, but if you’re constantly running on empty, don’t automatically write it off as a busy life or another night of rubbish sleep. Richards warns me that low iron can make even mundane tasks feel like an Olympic event, from climbing two flights of stairs without getting breathless to concentrating at work. “Dizziness, heart palpitations and restless legs, as well as “pica”—cravings for ice or even non-food substances—and itchy skin are also signs worth paying attention to, not simply pushing through,” he says.

Then there are the hair and skin changes fuelling the “ferritin face” frenzy online; “when ferritin falls below 15 micrograms per litre—particularly below 10—signs can become more visible, including increased hair shedding, a widening parting, brittle nails, dark circles, puffy eyes and a sallow complexion.” In severe cases, he says, women can look visibly unwell.

The stakes go beyond appearance. Richards points to The Lancet’s Global Burden of Disease Study when discussing how disabling iron-deficiency anaemia can be: “it can be more disabling than diabetes.” He estimates the average woman can spend up to eight years suffering from iron deficiency, including two to three years taking iron tablets. That’s a really long time to feel unlike yourself. So, if any of this sounds a little too familiar, don’t just put it down to being busy or run-down. Speak to your GP and ask whether your iron levels could be part of the picture.

Iron blood tests decoded: what tests to ask for and what your results mean

As we know, it’s not quite as simple as having your bloods done and being told everything looks fine. Heavy periods and diet are common causes of low iron in women who menstruate, but, as Richards points out, “other causes—including coeliac disease and hidden blood loss—may also need investigating.” So what should you be asking your GP to test for? Naturally, it depends on your medical history and symptoms, but here are a few key tests worth knowing about.

1. Full blood count (FBC):

This will check your haemoglobin and other blood components, helping identify anaemia. Disclaimer: A normal result doesn’t necessarily mean your iron stores are healthy.

2. Ferritin:

This test will measure your iron stores. If you’re concerned about low iron, this is a key number to ask for.

3. CRP:

Checks for inflammation, which can affect how your ferritin result is interpreted.

4. B12, folate and thyroid function:

These may also be checked because deficiencies or thyroid problems can cause symptoms like brain fog and fatigue that overlap with iron deficiency.

And even when you have those results in front of you, interpreting them isn’t always straightforward. “The tricky part,” Bate explains, “is that ferritin doesn’t always tell the full story on its own. Inflammation can cause levels to rise, potentially masking an iron deficiency, so results need to be considered alongside your symptoms, medical history and, where appropriate, other blood tests.”

One final tip: ask for the actual number, not just whether your results are “normal”. A result can fall within a lab’s reference range without necessarily answering every question about your symptoms. If you’re feeling unlike yourself, take those numbers back to your GP and ask whether further investigation or treatment is appropriate.

How to restore your iron levels and get back on track

If you’ve gotten this far and are feeling a little overwhelmed by how much of this you relate to, fear not; I have good news. Low iron and low ferritin are treatable, but Richards stressed that it’s about more than simply reaching for a packet of iron tablets and hoping for the best. “First up—you will need to treat the iron deficiency properly—the key to recovery is to replenish your iron stores and get to the bottom of why they’ve dropped in the first place.”

For many women, treatment starts with oral iron. “The standard regimen is an iron tablet containing 200 to 300 mg of the iron compound, providing around 80- 90 mg of elemental iron.” But here’s the catch: your body only absorbs a fraction of what you swallow. According to his numbers, that works out at around 200 to 240 mg of absorbed iron a month. What those numbers translate to: “If you’re trying to correct a deficit of roughly 1,000mg, it can take around six months to replenish those stores fully, although you may start to notice an improvement in how you feel after about a month.”

It’s also important to address what’s causing your levels to fall: “For vegetarians, I suggest considering a regular multivitamin containing iron. If heavy periods are behind your low levels, tackling the blood loss is also important. Tranexamic acid is one treatment that can help reduce blood loss by up to a third to a half, although you’ll need to speak to a healthcare professional about whether it’s suitable for you. Iron replacement may also be needed to replenish what you’ve lost.”

And if iron tablets aren’t doing the trick—or you struggle to tolerate them—an iron infusion may be another option. “These deliver iron directly into the bloodstream and can be useful in certain circumstances, although access and funding arrangements vary in the UK,” says Richards.

So, how do you know when you’re back on track? “Check your ferritin levels after three months of treatment, aiming for levels above 50, then test again six months later to make sure they’ve remained stable. The right target and timing will depend on your individual circumstances, so it’s worth agreeing a monitoring plan with your clinician.” Crucially, he warns me that treating the underlying cause matters just as much as replenishing your stores; otherwise, you risk ending up back where you started.

There’s something quietly reassuring about Richards’ final words to me: “Everything in life is about stability.” It’s a simple sentiment, but one that feels surprisingly reassuring when you consider how many women have come to accept feeling exhausted, foggy or just not quite themselves as their baseline.

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