Is 14mg of iron a day enough?

Reviewed and updated: 20 August 2026

Is 14mg of iron a day enough?

Is 14mg of iron a day enough? For most healthy adults in the UK, yes, 14mg a day is enough to cover normal daily needs, and here is the distinction almost nobody makes: 14mg is not a UK requirement at all, it is the Nutrient Reference Value used to calculate the %NRV printed on supplement labels. The actual UK reference nutrient intake is 14.8mg a day for women aged 19 to 49 and 8.7mg a day for men and for women over 50. So 14mg is generous for most people, fractionally short of the figure set for menstruating women, and not the right amount at all for anyone whose blood test has shown depleted iron stores.

I am Dr. Miron, and this question lands in my inbox constantly, usually from someone holding a 14mg tablet wondering whether they have bought the right strength. It is a better question than it looks, because the number on the pack and the number the UK actually recommends are two different things that happen to sit within a whisker of each other. Let me take you through what 14mg means, who it comfortably covers, who it does not, and what to do instead of quietly doubling the dose.

The short answer at a glance

• 14mg is the label NRV, not the UK requirement. It is the GB and EU benchmark used to work out the %NRV on the back of the pack, so a 14mg product declares 100% NRV.
• The UK reference nutrient intake is 8.7mg for men and for women aged 50 and over. 14mg sits comfortably above that.
• The UK reference nutrient intake is 14.8mg for women aged 19 to 49. 14mg is fractionally under it, and a normal varied diet closes that small remainder easily.
• It is a maintenance amount, not a correction amount. Rebuilding stores that a blood test has shown to be low takes considerably more, under medical supervision.
• What you absorb matters far more than what you swallow. Only a modest fraction of dietary and supplemental iron crosses the gut wall, and your own iron status is the biggest single influence on that.
• One honest caution. If you feel persistently drained, ask your GP for a full blood count and a ferritin test before you increase the dose. Fatigue has many causes and iron is only one of them.

What 14mg actually is, and why it is on the pack

The number on the front of the box is doing something quite specific, and it is not what most people assume.

Under GB labelling rules, iron has a Nutrient Reference Value of 14mg. The NRV is a single labelling benchmark for the whole adult population, chosen so that manufacturers across the market can print a comparable %NRV figure on every product. It is deliberately one number, because a label cannot ask how old you are or whether you menstruate. So a product delivering 14mg of iron declares 100% NRV, and that is precisely why 14mg is such a common strength. It is a design target, not an arbitrary figure and not a medical recommendation aimed at you personally.

The UK reference nutrient intake is a different animal. The RNI is a dietary recommendation, set separately by sex and life stage, intended to cover the needs of the great majority of the group it applies to. Because the NRV and the RNI serve different purposes, they do not have to match, and for iron they nearly do but not quite.

The second thing worth checking on any label is that the figure refers to elemental iron, meaning the iron itself, rather than the weight of the compound carrying it. This trips up a lot of people. Iron in supplements comes bound into a salt or a chelate, and the carrier weighs considerably more than the iron inside it. Ferrous fumarate, the form we use, is roughly 33% elemental iron by weight, so about 43mg of ferrous fumarate salt is needed to deliver around 14mg of elemental iron. A reputable UK label always declares the elemental figure with the %NRV alongside it. If a product shouts about the compound weight on the front and hides the elemental figure on the back, read more carefully before you buy.

The UK reference intakes, and where 14mg sits against each one

The UK does not use a single iron number for everybody, and that is the root of nearly all the confusion around this question. Here is how 14mg measures up against each group.

Men aged 19 and over: 8.7mg a day

14mg is comfortably above the male reference intake, roughly 60% more. For a man eating a normal mixed diet, a daily iron supplement is often unnecessary in the first place, because men have no monthly losses to replace and the body has no easy route for shedding surplus iron. If you are a man taking iron without a specific reason, that is worth a conversation with your GP rather than a habit you simply continue.

Women aged 19 to 49: 14.8mg a day

This is the group the question is usually really about. 14mg is 0.8mg under the reference intake, which sounds like a shortfall and in practice almost never is, because the RNI describes total daily intake from all sources and a normal diet supplies several milligrams before you take anything. A supplement is there to top up a diet, not to replace one. Where 14mg genuinely may not be enough is at the heavy end of menstrual losses, which I come back to below.

Women aged 50 and over: 8.7mg a day

Once menstrual losses stop, iron requirements fall back to the same figure used for men, and 14mg becomes generous. Many women carry on with the iron supplement they took in their forties out of habit. After the menopause it is worth asking whether you still need it, because iron accumulates rather than clears.

Teenagers

Adolescent girls aged 11 to 18 have a UK reference intake of 14.8mg a day, the same figure used for adult women of reproductive age, while boys of the same age are set at 11.3mg. Growth spurts and the onset of periods make this a genuinely higher-need window, but supplementation in this age group is a conversation for a GP rather than a decision made off a shelf.

The reason women of reproductive age need roughly 70% more iron than men is straightforward physiology. Everybody loses in the region of 1mg of iron a day through shed cells in the gut and skin, and menstruation adds a further average loss on top. The reference intake is built to replace those losses across a whole population, with a margin built in for people at the heavier end of the range. It is a population figure, not a personal prescription, which is exactly why a blood test beats arithmetic when something feels off.

Is 14mg enough for a menstruating woman?

For most, yes. For some, no, and the difference is menstrual blood loss, which varies enormously between individuals and is very poorly estimated by the person experiencing it.

A typical period loses somewhere around 30 to 40ml of blood, which works out at roughly 0.5mg of iron a day averaged across the month. At that level, 14mg of supplemental iron on top of a reasonable diet is comfortably sufficient. But menstrual loss above about 80ml a cycle is classified as heavy menstrual bleeding, and at that end of the range the iron cost can outpace what a maintenance supplement replaces, month after month, until stores quietly run down. The tell is not usually dramatic. It is a slow slide into tiredness that sleep does not fix.

Practical signals that your losses may be at the heavier end include soaking through a pad or tampon every hour or two, passing clots larger than a ten pence piece, bleeding for more than seven days, or needing double protection. If any of that sounds familiar, the answer is not a bigger tablet. It is a GP appointment, a ferritin test, and a conversation about the bleeding itself, because heavy periods have causes worth identifying. Iron replacement is the downstream fix, not the upstream one.

Iron in pregnancy is a different question entirely

Iron requirements rise substantially in pregnancy, driven by expanding maternal blood volume, the growing baby and the placenta. This is the one area where I would ask you to ignore general guidance, including mine, and follow your midwife or GP.

The UK approach is not to supplement every pregnancy routinely. Iron is offered where a blood test indicates it is needed, which is why antenatal care includes haemoglobin checks at booking and again later in pregnancy. That is a deliberate policy position, not an oversight.

The underlying research is worth knowing about, framed as science rather than as a reason to self-supplement. According to PubMed, a 2024 Cochrane systematic review pooling 57 trials in 48,971 women reported that daily oral iron during pregnancy may lower rates of maternal anaemia and of iron deficiency at term, with moderate-certainty evidence for lower rates of iron-deficiency anaemia at term, while evidence for most other maternal and infant outcomes was uncertain or showed little difference between groups (Finkelstein et al., 2024, Cochrane Database of Systematic Reviews). Note how carefully that is worded by the authors themselves: the certainty ratings range from moderate down to very low depending on the outcome. That is an honest evidence base, not a slam dunk, and it is one reason UK practice tests rather than blanket-supplements.

The practical point for this article is simple. If you are pregnant or trying to conceive, do not decide your iron dose from a blog. Take the folic acid and vitamin D that UK guidance recommends in pregnancy, and let your midwife decide about iron on the basis of your bloods.

Vegetarians, vegans and the non-haem problem

There is a persistent myth that plant foods lack iron. They do not. Lentils, chickpeas, tofu, dark leafy greens, pumpkin seeds and fortified cereals all supply meaningful amounts. The issue is not how much iron is on the plate, it is how much of it gets through the gut wall.

Because plant iron is absorbed less efficiently, guidance in several countries suggests vegetarians and vegans may need something in the order of 1.8 times the standard intake to achieve the same absorbed amount. Applied to the UK figures, that pushes an effective target for a vegetarian woman of reproductive age well above 14mg of dietary intake, which is precisely why a supplement earns its place in a plant-based diet more readily than in an omnivorous one.

The bigger lever, though, is not the dose. It is pairing. A vitamin C source eaten in the same meal as your plant iron meaningfully improves uptake, and it costs nothing: peppers in the stir fry, tomatoes in the dhal, a squeeze of lemon over the greens, a glass of orange juice with fortified cereal. If I could persuade a vegetarian reader to change one habit, it would be that one rather than the tablet strength.

Haem versus non-haem iron, and why the difference matters

Dietary iron comes in two chemically distinct forms, and they behave so differently in the gut that lumping them together as one number is misleading.

Haem iron is iron bound inside the haemoglobin and myoglobin of animal tissue. Red meat, liver, and to a lesser extent poultry and oily fish such as sardines supply it. It is taken up through its own route, largely intact, and it is comparatively indifferent to what else is on the plate. Absorption is efficient, often quoted in the region of 15% to 35%, and it is the reason a modest portion of red meat contributes disproportionately to iron status.

Non-haem iron is the form in plants, dairy, eggs and every iron supplement including ours. It has to be reduced from ferric to ferrous form at the brush border before it can cross via the divalent metal transporter, and that step is where it becomes vulnerable. Anything in the meal that binds iron, and there is a long list, competes at exactly that point. Absorption is far more variable, commonly cited from as low as 2% up to around 20% depending on the meal and on the person.

According to PubMed, a review of isotope and intake studies estimated overall iron bioavailability at roughly 14% to 18% from mixed diets and only 5% to 12% from vegetarian diets in people with no iron stores, and made the further point that an individual's own iron status generally influences absorption more than the composition of the diet does (Hurrell and Egli, 2010, American Journal of Clinical Nutrition).

That last clause deserves reading twice. When stores are low, the gut upregulates absorption. When stores are replete, it dials it down. Your body is already doing a great deal of the regulating for you, which is both reassuring and a reason not to force the issue with ever larger doses.

What boosts absorption and what blocks it

Since absorption is the bottleneck, this is where the practical wins live. Every one of these applies to non-haem iron, meaning both your plant foods and your supplement.

What helps

• Vitamin C. Ascorbic acid keeps iron in the absorbable ferrous form and helps hold it in solution through the small intestine. This is well established mechanistically and is why our iron tablets build vitamin C into the formula alongside B12 and folic acid rather than leaving you to stack it yourself.
• The so-called meat factor. A small amount of animal protein in a meal improves uptake of the non-haem iron eaten alongside it. Useful to know if you eat meat occasionally rather than never.
• An empty-ish stomach, if you can tolerate it. Iron is absorbed better without a full meal competing, though this is exactly the scenario most likely to cause nausea, so comfort usually wins.
• Spacing rather than stacking. Taking your iron away from other mineral supplements avoids direct competition at the transporter.

What hinders

• Tea and coffee. Polyphenols and tannins bind non-haem iron efficiently. A strong cup of tea with a meal can cut absorption of that meal's iron substantially. An hour either side is enough spacing.
• Calcium. Uniquely, calcium interferes with both haem and non-haem iron. Milk, yoghurt, cheese and calcium supplements are all worth separating from your iron dose.
• Phytates. Found in wholegrains, legumes, nuts and seeds. Soaking, sprouting and fermenting reduce them, which is one quiet advantage of sourdough over standard bread.
• Zinc and other divalent minerals. They compete for the same transporter when taken together in supplement form.
• Antacids and proton pump inhibitors. Stomach acid assists the reduction step, so anything that suppresses it reduces uptake. If you take a PPI long term, mention it when you discuss iron with your GP.
• Eggs. Phosvitin in egg yolk binds iron. A minor effect, but a real one.

An honest caveat on the vitamin C story

The vitamin C effect is real, but it is oversold, and I would rather tell you that than let you expect too much of it. According to PubMed, a randomised trial in 440 adults with iron deficiency anaemia found that adding 200mg of vitamin C to a 100mg iron tablet produced haemoglobin and ferritin recovery equivalent to iron alone, suggesting extra vitamin C is not essential at those therapeutic amounts (Li et al., 2020, JAMA Network Open). The absorption effect matters most for non-haem iron from food and for lower-dose supplements taken alongside inhibitors. It is not a multiplier that rescues a poorly chosen routine, and anyone selling it that way is overstating it.

Why 14mg of intake is not 14mg of iron absorbed

Here is the part most articles skip, and it is the honest core of the answer. Iron is unusual among minerals because the body has no real mechanism for excreting a surplus. Balance is therefore controlled almost entirely at the point of absorption, and absorption is deliberately conservative.

Run the arithmetic with the figures above. A 14mg intake on a mixed diet might deliver somewhere in the region of 2mg to 2.5mg of absorbed iron, and rather less on a plant-based diet. That is not a flaw in the supplement. It is roughly what a person in normal iron balance needs in order to replace daily losses, which is exactly what a maintenance dose is for.

It also explains immediately why 14mg is the wrong tool for refilling stores that are already low. You cannot meaningfully refill a reservoir by matching the daily leak.

The hormone doing the regulating is hepcidin, and it responds to a dose within hours. According to PubMed, in iron-depleted women, giving supplements as a single morning dose rather than split through the day, and on alternate days rather than consecutive days, raised hepcidin less and improved fractional absorption (Stoffel et al., 2017, The Lancet Haematology). A later review from the same group concluded that morning doses of 60mg to 120mg on alternate days may be an optimal regimen for women with iron deficiency (Stoffel et al., 2020, Molecular Aspects of Medicine).

Both of those relate to the higher amounts used for correcting a deficiency, not to a 14mg maintenance dose, where straightforward daily use is the sensible approach. But the underlying principle is worth carrying with you: taking more iron at once does not produce proportionally more absorbed iron, because your own physiology pushes back.

Signs your iron may be running low

Iron depletion happens in stages rather than all at once, and it is entirely possible to feel the early stages while a standard blood count still looks normal.

Commonly reported signs include tiredness that rest does not resolve, breathlessness on mild exertion such as stairs, unusual paleness, brittle or spoon-shaped nails, hair shedding, headaches, restless legs, cold hands and feet, poor concentration, mouth ulcers or cracks at the corners of the mouth, and occasionally pica, a craving for non-food items such as ice.

Not one of those is specific to iron. Every single one has other plausible causes, from thyroid problems to B12 deficiency to simply not sleeping enough. That is exactly why guessing is a poor strategy and a blood test is a good one. If tiredness is your main complaint, what vitamins help with tiredness sets out which nutrients carry a recognised role, and B12 deficiency and who is most at risk covers the other common culprit that gets mistaken for low iron.

Ferritin versus haemoglobin, and why the distinction matters

If you take one technical point from this article, make it this one, because it is the single most useful thing to understand before you speak to your GP.

Haemoglobin measures the oxygen-carrying protein currently in your red blood cells. It is the number that defines anaemia. Crucially, it is a late indicator. Your body will strip its reserves to keep haemoglobin normal for as long as it can.

Ferritin is the storage protein, and serum ferritin broadly tracks how much iron you have banked. It falls first. Someone can have entirely normal haemoglobin and a ferritin sitting near the floor, which is the classic picture of iron deficiency without anaemia, and it can absolutely make you feel rough.

According to PubMed, a Lancet seminar on iron deficiency anaemia noted that serum ferritin, transferrin saturation, soluble transferrin receptor and the receptor-to-ferritin index are more accurate than the classic red cell indices for identifying iron deficiency anaemia, and highlighted hepcidin's central role in iron homoeostasis (Lopez et al., 2016, The Lancet).

One complication worth knowing about: ferritin is also an acute-phase protein, so it rises with inflammation, infection, liver disease and obesity. A ferritin that looks reassuringly mid-range in someone with an inflammatory condition can still mask genuinely low stores, which is why clinicians often look at C-reactive protein and transferrin saturation alongside it. If you want the practical detail on rebuilding stores once you have your result, we cover it in how to increase ferritin.

When to get a blood test rather than self-supplement

My honest position is that a 14mg maintenance supplement is a reasonable thing to take without testing if you are in a higher-need group and feel fine. Anything beyond that should follow a blood test rather than a hunch. Ask your GP if any of the following apply.

• Persistent fatigue lasting more than a few weeks that rest does not shift.
• Heavy or prolonged periods, as described above.
• You are already taking iron and feel no different after two to three months.
• Any change in bowel habit, blood in the stool, or unexplained weight loss, particularly over 50. Low iron in a man or a post-menopausal woman needs a cause identified, because the gut is the usual route for unexplained loss.
• A diagnosed condition affecting absorption, including coeliac disease, inflammatory bowel disease, or previous gastric surgery.
• Regular blood donation, since each donation removes a meaningful quantity of iron that has to be rebuilt.
• You are pregnant, or planning to be.

Ask specifically for a full blood count and ferritin. The full blood count alone can look normal while stores are empty, and that is the exact scenario people spend months trapped in.

Maintenance versus rebuilding depleted stores

These are two entirely different situations calling for two different amounts, and conflating them is the most common mistake I see.

Maintenance. You eat reasonably, you have no known problem, and you want to be sure you consistently meet the reference intake. Perhaps you are vegetarian, or your periods are on the heavier side of average, or you simply want the insurance. This is exactly what a 14mg daily supplement is designed for, and it does that job well.

Correction. A blood test has shown low ferritin or iron deficiency anaemia. The amounts used here are substantially larger. For context, prescription-strength ferrous fumarate 210mg tablets deliver around 68mg of elemental iron each, roughly five times a 14mg maintenance dose, and are used under medical supervision for a defined period rather than indefinitely, typically continuing for around three months after haemoglobin normalises so that stores refill rather than merely the blood count recovering.

Chasing that outcome by swallowing several 14mg tablets a day is not a sensible substitute. You would be self-prescribing without the blood test that tells you whether iron is the problem in the first place, without the follow-up test that tells you when to stop, and without anyone asking why your iron was low. That last question is often the important one.

Supplement forms and how well they are tolerated

The form of iron changes the elemental content, the price and, most noticeably to you, the gut comfort. Here is the honest landscape.

• Ferrous sulfate. The NHS workhorse, cheap and effective, around 20% elemental iron. It is also the form most associated with constipation and nausea, which is the usual reason people abandon a prescription.
• Ferrous fumarate. Around 33% elemental iron, so fewer milligrams of carrier for the same delivered dose. This is the form we use in our iron tablets, and it is generally regarded as a reasonable balance of absorption and tolerability.
• Ferrous gluconate. Only about 12% elemental iron, so a larger tablet for a smaller dose, sometimes chosen for gentleness.
• Ferrous bisglycinate. An amino acid chelate, roughly 20% elemental iron, marketed as the gentle option and priced accordingly.
• Iron polysaccharide complexes and liposomal forms. Newer, generally gentler, and with a thinner evidence base than the traditional salts.

On bisglycinate specifically, the evidence is genuinely interesting but narrower than the marketing suggests. According to PubMed, a systematic review and meta-analysis of 17 randomised controlled trials found that ferrous bisglycinate produced higher haemoglobin concentrations in pregnant women and fewer reported gastrointestinal adverse events compared with other iron supplements, with a non-significant trend for higher ferritin, while no significant differences in haemoglobin or ferritin were detected among children, and the authors concluded more trials are needed in other populations (Fischer et al., 2023, Nutrition Reviews).

Read that carefully and you will notice the tolerability signal is real but the population it was demonstrated in is specific. It would be overstating things to tell you bisglycinate is definitively gentler for every adult, and I would rather be straight with you: our formula uses ferrous fumarate at a maintenance strength, which most people tolerate perfectly well precisely because 14mg is a modest dose. The gut trouble people associate with iron is overwhelmingly a feature of the much larger correction doses, not of maintenance amounts.

How much is too much?

Because the body cannot readily offload a surplus, more is emphatically not better with iron.

The NHS position is that taking 17mg or less a day of iron supplements is unlikely to cause harm, and 14mg sits comfortably inside that. Above it, the first complaint is almost always the gut: constipation, nausea, stomach discomfort and darkened stools. The dark stools are harmless and expected, but the constipation is the main reason people stop taking iron altogether. Supplemental iron much above roughly 20mg a day commonly causes it, and we cover how to manage that in iron supplement without constipation.

Beyond gut discomfort, sustained excess is a genuine concern rather than a theoretical one, because surplus iron accumulates in the liver, heart and pancreas over years. There is no meaningful benefit to exceeding your requirement, and unlike the water-soluble vitamins there is no easy exit route. Two firm cautions from me. Never take high-dose iron long term without a blood test and a doctor's involvement. And keep iron supplements well out of reach of children, because accidental iron overdose in a small child is a genuine medical emergency and one of the more common serious paediatric poisonings.

Who should not supplement without medical advice

Some people should not take iron casually at all, and the most important group is those with an inherited tendency to load iron.

Hereditary haemochromatosis, most often linked to homozygous C282Y variants in the HFE gene, causes iron to be absorbed in excess of need and deposited in tissue over decades. It is one of the more common genetic conditions in people of Northern European ancestry, which makes it relevant in the UK specifically. Its clinical picture is only partly predictable from genotype: according to PubMed, an analysis of 1,294 male and 1,596 female C282Y homozygotes in UK Biobank found that penetrance to liver disease was partly explained by additional common genetic variants influencing iron levels, with a substantially raised likelihood of recorded liver fibrosis or cirrhosis in men with a higher iron polygenic score (Pilling et al., 2022, Hepatology).

The practical takeaway is not alarm. It is that if you have a family history of haemochromatosis, unexplained joint pain, liver abnormalities or a previously high ferritin with high transferrin saturation, iron supplements are not for you unless a clinician says otherwise. The same caution applies to anyone with an iron-loading anaemia, anyone who has had repeated transfusions, and anyone with active infection, where routine supplementation is usually deferred.

Food sources worth knowing

Supplements sit on top of a diet, not instead of one, and a few kitchen habits go a long way.

Haem sources, best absorbed: beef and lamb, liver and other offal, sardines and other oily fish, and to a lesser degree pork and poultry, particularly the darker meat.

Non-haem sources, plentiful but less efficiently absorbed: lentils, chickpeas and beans, tofu and tempeh, dark leafy greens such as kale and spring greens, dried apricots and figs, pumpkin and sesame seeds, cashews, dark chocolate, and fortified breakfast cereals, which in the UK are a genuinely significant contributor to national iron intake.

Two practical notes. Spinach has an outsized reputation and a high oxalate content that limits how much of its iron you actually get, so it is a decent food but not the iron powerhouse of folklore. And cooking acidic foods in a cast iron pan does transfer a small amount of usable iron into the meal, which is a pleasant piece of trivia rather than a strategy.

What iron actually does in the body

Iron sits at the centre of oxygen transport. It is built into haemoglobin, which carries oxygen through the blood, and into myoglobin, which holds oxygen in muscle. It also sits inside the iron-sulphur clusters and cytochromes of the mitochondrial electron transport chain, which is where the connection to energy comes from. Run short and the shortfall shows up as breathlessness and tiredness precisely because oxygen delivery and cellular energy production are both affected.

In terms of the specific functions recognised for iron, it contributes to normal formation of red blood cells and haemoglobin, to normal oxygen transport in the body, to normal energy-yielding metabolism, to normal cognitive function, to the normal function of the immune system, and to the reduction of tiredness and fatigue. It also has a role in the process of cell division.

That is why the supporting nutrients in our formula are there rather than being decoration. Vitamin C increases iron absorption, which is the single most useful thing you can pair with a non-haem source. Vitamin B12 contributes to normal red blood cell formation, and folate contributes to normal blood formation, so between them they cover the other two nutrient deficiencies that most commonly sit behind the same tired, breathless picture people blame on iron alone. The full reasoning behind how the four fit together is in ferrous fumarate, iron with vitamin C and folic acid.

How to get more out of the 14mg you already take

Since absorption is the bottleneck, the wins are almost all in how you take it rather than how much you take.

• Take it with water, away from meals if your stomach allows. If it does not, a small snack is a fair trade against skipping the dose.
• Keep tea and coffee at least an hour either side. This is probably the highest-return change most people can make, and the one most often ignored.
• Separate it from dairy, calcium and other mineral supplements. Two hours is plenty.
• Pair it with a vitamin C source if your product does not already include one. Ours does.
• Be consistent rather than clever. A dose you actually take every day beats an optimised routine you abandon in a fortnight.
• Give it time. Iron status changes over weeks and months, not days. Red cell turnover alone runs to about 120 days, so judging a change after a fortnight tells you very little.

What to realistically expect

If your iron status is genuinely fine and you take 14mg a day, you should expect to feel exactly the same, and that is the correct outcome. A maintenance supplement is insurance against a shortfall, not a stimulant. Nothing about a normal daily requirement being met produces a noticeable lift.

If your stores were genuinely low and iron is the reason, improvement tends to be gradual and is usually described in retrospect: someone notices around week eight that the stairs stopped registering. Haemoglobin typically responds within a few weeks to a correcting dose, but refilling ferritin takes months. Anyone promising you a transformation in days is selling something other than iron.

And if you have taken iron consistently for three months and feel no different, that is genuinely useful information. It usually means iron was not the limiting factor, and it is a good moment to go back to your GP rather than to escalate the dose. If you are reviewing your whole routine rather than one nutrient, how to compare multivitamin formulas is a sensible place to start, and you can browse everything we have written by ingredient in the supplement guides hub.

A few cautions worth knowing

Iron competes with, and interferes with, a surprising number of things, so a little spacing goes a long way.

Keep your dose at least two hours away from levothyroxine, tetracycline and quinolone antibiotics, bisphosphonates, methyldopa, levodopa and penicillamine. Antacids and proton pump inhibitors reduce absorption, as do calcium, zinc and magnesium supplements taken at the same moment. If you are pregnant, breastfeeding, taking regular medication, or living with a chronic condition, check with your GP or pharmacist before starting iron rather than after.

Where we stand on quality

Our iron tablets are formulated in the UK, manufactured in GMP-certified facilities and tested for purity and heavy metals at our GMP-certified facility. The label declares elemental iron with the %NRV plainly, because a number you cannot interpret is not transparency, and the supporting nutrients are listed at their actual amounts rather than hidden inside a blend. If you want to see how we think about evidence more generally, why we reference medical research explains the standard we hold ourselves to, and you can see the wider range on the Pure Vitamins UK home page.

Frequently asked questions

Is 14mg of iron a day enough for a woman?

For a woman aged 19 to 49 it is essentially a full daily dose, since the UK reference nutrient intake is 14.8mg a day and a normal diet closes the small remainder. For a woman aged 50 and over, whose reference intake is 8.7mg, 14mg is generous. It is a maintenance amount in both cases, not an amount for rebuilding stores that a blood test has shown to be low.

Is 14mg the same as the UK recommended daily amount for iron?

No, and this is the most common misunderstanding. 14mg is the Nutrient Reference Value, a single labelling benchmark used to calculate the %NRV printed on packs. The UK reference nutrient intake is set separately by group: 8.7mg a day for men and for women aged 50 and over, and 14.8mg a day for women aged 19 to 49. The two figures are close for iron, but they are not the same thing.

Is 14mg of iron too much for a man?

No. It is above the UK reference intake of 8.7mg for men aged 19 and over, but it sits within the NHS guidance that 17mg or less a day of supplemental iron is unlikely to cause harm. Men without a confirmed need generally do not require an iron supplement at all, so it is worth asking whether you need one before taking it daily.

Is 14mg of iron enough to raise low ferritin?

Usually not. Rebuilding depleted stores takes considerably more elemental iron over several months, which is why prescribed doses are far higher and are continued for a period after haemoglobin normalises. If a blood test has shown low ferritin, speak to your GP rather than doubling up on a maintenance tablet.

Is 14mg of iron enough in pregnancy?

Iron requirements rise in pregnancy, and UK antenatal care checks haemoglobin rather than supplementing everyone routinely. Do not set your own iron dose in pregnancy. Follow your midwife or GP, who will base the decision on your blood results.

How much ferrous fumarate gives 14mg of iron?

Ferrous fumarate is roughly 33% elemental iron by weight, so about 43mg of ferrous fumarate supplies around 14mg of elemental iron. Always read the elemental iron figure and the %NRV on the label rather than the compound weight on the front of the pack.

Is 14mg of iron enough for a vegetarian or vegan?

Possibly not on its own, because non-haem iron from plants is absorbed less efficiently, so the effective intake is lower than the label figure suggests. The most useful adjustment is usually not a bigger tablet but pairing iron-rich meals with a vitamin C source and keeping tea and coffee away from them.

Can I take 14mg of iron every day?

For most healthy adults, yes. It is a maintenance amount within NHS guidance for supplemental iron. Take it with water, ideally away from tea, coffee and dairy, and check with your GP first if you are pregnant, taking medication or living with a condition that affects iron.

How long does it take for iron supplements to make a difference?

Longer than most people expect. If stores were low, haemoglobin generally responds over a few weeks while ferritin takes months to refill, and red cell turnover alone runs to about 120 days. Judge a maintenance dose over three months, not three weeks, and if nothing has changed by then, go back to your GP rather than increasing the amount.

Shop Iron with Vitamin C, B12 & Folic Acid

Dr. Miron, Founder of Pure Vitamins UK

Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle. This article is for information only and is not medical advice. Speak to your GP or pharmacist if you are pregnant, breastfeeding, taking medication or living with a medical condition.