The most common symptoms of low ferritin in women are fatigue that sleep does not fix, breathlessness on mild exertion, hair shedding, brain fog, feeling cold, and restless legs at night. The important part, and the part most often missed, is that all of these can appear while a standard full blood count comes back completely normal. Ferritin is the storage form of iron. It falls first, and haemoglobin only drops later, once the reserves are gone.
That sequence is why so many women are told their bloods are fine while they feel anything but. A review of the effect of iron deficiency and anaemia on women's health in Anaesthesia makes the distinction clearly: iron deficiency without anaemia is its own state, it is common in women, and it carries symptoms of its own.
It is also worth saying plainly that none of these symptoms is specific to iron. Thyroid disease, sleep apnea, depression, coeliac disease and perimenopause itself all produce overlapping pictures. The point of knowing the symptoms is not to self-diagnose. It is to have a specific enough conversation that the right test gets ordered.
The symptoms most women recognise
Fatigue that rest does not resolve. This is the headline symptom and the least specific one. What distinguishes it is that it does not respond to a good night's sleep. A randomised, double-blind, placebo-controlled trial published in the BMJ tested iron supplementation for unexplained fatigue in women who were not anaemic, and is one of the foundations for taking non-anaemic iron deficiency seriously.
Breathlessness on ordinary exertion. One flight of stairs, carrying shopping, a hill you used to walk without noticing. Iron carries oxygen, so less iron means less oxygen delivery per heartbeat.
Heart racing or pounding on mild effort, as the heart compensates for reduced oxygen-carrying capacity.
Pale skin, or an unusual pallor in the inner eyelids, gums, or nail beds.
Feeling cold when the people around you are comfortable, particularly cold hands and feet.
Dizziness or lightheadedness on standing.
Headaches without another clear cause.
The symptoms most women do not connect to iron
This is the more useful section, because these are the ones that get attributed to stress, age, or bad luck.
Restless legs at night
An uncomfortable, hard-to-describe urge to move the legs, worse in the evening and at rest, relieved by moving. The association with low iron is well recognised in the sleep medicine literature, and contemporary reviews of restless legs syndrome treat checking iron status as a standard part of assessment. If you have restless legs, ask for ferritin specifically. Clinicians managing restless legs often work to a higher ferritin target than the laboratory's lower reference limit.
Craving ice, or non-food substances
Compulsively chewing ice has a name, pagophagia, and it belongs to a broader phenomenon called pica. A scoping review of the association between pica and iron-deficiency anaemia covers the link, and the 2025 JAMA review of iron deficiency in adults lists it among the recognised features.
This is the single most specific clue on the list. Most fatigue is not iron. Chewing through a glass of ice every afternoon is unusual enough to be worth mentioning to a doctor unprompted, and many women never think to raise it because it does not feel like a medical symptom.
Hair shedding
More hair in the brush and the shower drain. The relationship between iron and hair is genuinely associational rather than proven, which we cover honestly in hair shedding and ferritin. It is still worth testing, because it is cheap and correctable.
Brittle or spoon-shaped nails, and cracked mouth corners
Nails that break easily, develop ridges, or in more advanced deficiency curve upward into a spoon shape. Painful splits at the corners of the mouth, or a sore, smooth tongue, also appear in longstanding deficiency.
Poor concentration and brain fog
Losing the thread mid-sentence, rereading paragraphs, forgetting why you walked into a room. Easy to blame on being busy or on perimenopause, and frequently overlapping with both.
Exercise that suddenly feels harder
Runs that used to be routine, recovery that takes days instead of hours, a heart rate that climbs faster than it used to. Often the earliest change in women who train, and often blamed on age.
Low mood and reduced motivation
Iron is involved in neurotransmitter synthesis. Low mood is not proof of deficiency, and depression deserves its own assessment, but it belongs on the list.
Getting ill more often
Iron has a role in immune function, and frequent minor infections can accompany depletion.
Related reading: low ferritin with normal haemoglobin, what counts as a good ferritin level, and iron deficiency versus anemia.
Why women are affected disproportionately
A review of iron metabolism and iron deficiency anaemia in women in Fertility and Sterility sets out the reasons, and they are mostly structural rather than dietary.
- Menstruation. Every cycle removes iron. Heavy or prolonged bleeding removes considerably more, and many women underestimate their own flow because they have no comparison. See heavy periods and iron deficiency.
- Perimenopause. Cycles often become heavier and more erratic before they stop, so iron loss frequently increases in the years women assume it is winding down. See low ferritin in perimenopause.
- Pregnancy and birth, which draw heavily on stores and add blood loss. See postpartum iron recovery.
- Lower intake, particularly on plant-based diets, where absorption is also less efficient. See iron deficiency in vegetarians.
Get the number, not the reassurance
Ask for ferritin specifically. A full blood count measures haemoglobin, which falls late. You can have depleted stores and a normal full blood count at the same time, which is the exact situation that produces "your bloods are fine" alongside months of exhaustion.
Then ask for the actual figure rather than the word "normal." Reference ranges are wide, and their lower bound is set to flag anaemia risk rather than to define where women feel well. A result in the teens is inside many reference ranges and is still a very thin reserve.
One important caveat: ferritin rises with inflammation and infection. It is an acute-phase reactant, so a result taken during an illness, a flare of an inflammatory condition, or shortly after surgery can read misleadingly high and mask a real deficiency. A clinician can interpret it alongside other markers. Our guide to asking your doctor for a ferritin test covers how to have that conversation, and understanding your iron blood test explains the other numbers on the panel.
Symptoms that need a doctor rather than a supplement
- Blood in the stool, or black tarry stools
- Unexplained weight loss
- Chest pain, or breathlessness at rest
- Fainting
- Very heavy periods, flooding, or bleeding between periods or after menopause
- Iron deficiency in a woman past menopause, which always warrants investigation of the cause
Iron deficiency is a finding, not a diagnosis. Something is causing it. In menstruating women it is usually blood loss through periods, but gut causes including coeliac disease, ulcers and bowel conditions matter, and they matter more when the pattern does not fit.
Where a supplement fits
If testing shows your iron is low and your clinician agrees supplementation is appropriate, the practical obstacle is usually tolerability. That is why we make Iron Glow Up Strips, an oral dissolving strip that delivers iron through the tissue of the mouth rather than a tablet passing through the stomach. It is a daily iron supplement, not a treatment for anaemia, and it does not replace a ferritin test or your doctor's advice.
Frequently asked questions
What are the first signs of low ferritin in women?
Usually fatigue that a good night's sleep does not fix, along with breathlessness on stairs, feeling cold, and reduced exercise tolerance. Hair shedding, brain fog and restless legs often follow. The distinctive early clue is craving and chewing ice, which is unusual enough to be worth mentioning to a doctor. All of these can appear while a standard full blood count is completely normal, because ferritin falls before haemoglobin does.
Can I have low ferritin symptoms with normal blood tests?
Yes, and this is the most important thing to understand. A full blood count measures haemoglobin, which falls late in iron depletion. Ferritin measures the stores, and those fall first. Iron deficiency without anaemia is a recognised state with its own symptoms, which is why a normal full blood count does not rule it out. Ask for ferritin specifically.
Why do I crave ice?
Compulsively chewing ice is called pagophagia, a form of pica, and it has a recognised association with iron deficiency. It appears in the 2025 JAMA review of iron deficiency in adults and in a scoping review of pica and iron-deficiency anaemia. It is one of the more specific clues on the whole list, so mention it to your doctor even though it does not feel like a medical symptom.
Can low iron cause restless legs?
There is a well-recognised association, and checking iron status is a standard part of assessing restless legs syndrome. If you have restless legs, ask for ferritin specifically, and be aware that clinicians treating it often work to a higher ferritin target than the laboratory's lower reference limit. Restless legs also has other causes, so it warrants proper assessment rather than self-treatment.
Could my symptoms be something other than iron?
Very possibly. Thyroid disease, sleep apnea, depression, coeliac disease, vitamin B12 deficiency and perimenopause all produce overlapping symptoms, and several of them travel with iron deficiency rather than instead of it. That is the argument for testing rather than guessing, and for asking about thyroid function and B12 at the same appointment.
My ferritin is 20 and my doctor said it is normal. Is it?
It is usually inside the reference range, so a lab will not flag it, but it is a thin reserve. Reference ranges are wide and their lower bound is set to identify anaemia risk, not the level at which women feel well. Many clinicians treat ferritin below about 30 as a sign of depleted stores. Get the actual number rather than the word "normal", and discuss your symptoms alongside it.
When should I see a doctor urgently?
Promptly for blood in the stool or black tarry stools, unexplained weight loss, chest pain, breathlessness at rest, fainting, or bleeding between periods or after menopause. Iron deficiency in a post-menopausal woman always needs the cause investigated. Iron deficiency is a finding rather than a diagnosis, so something is producing it, and in some cases that something matters more than the iron.
Sources & further reading
- Benson CS, et al. The effect of iron deficiency and anaemia on women's health. Anaesthesia, 2021. PubMed
- Verdon F, et al. Iron supplementation for unexplained fatigue in non-anaemic women: double blind randomised placebo controlled trial. BMJ, 2003. PubMed
- Auerbach M, et al. Iron deficiency in adults: a review. JAMA, 2025. PubMed
- Ganesan PR, et al. The association between pica and iron-deficiency anemia: a scoping review. Cureus, 2023. PubMed
- Gossard TR, et al. Restless legs syndrome: contemporary diagnosis and treatment. Neurotherapeutics, 2021. PubMed
- Cappellini MD, et al. Iron metabolism and iron deficiency anemia in women. Fertil Steril, 2022. PubMed
This article is for general education and is not medical advice. It is not a substitute for diagnosis or treatment by a qualified clinician. Iron deficiency always has an underlying cause, so persistent symptoms should be assessed by a doctor rather than self-treated.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
