How to Increase Ferritin Levels: Diet, Supplements and What the Evidence Shows

What is ferritin and why does it matter?

Ferritin is the protein your body uses to store iron. It acts as a buffer — sequestering iron when intake exceeds immediate needs and releasing it when demand rises. Serum ferritin, measured through a simple blood test, is the most reliable single indicator of total body iron stores.

It is worth understanding the difference between ferritin and haemoglobin, because the two are often conflated. Haemoglobin is the iron-containing protein in red blood cells that carries oxygen from your lungs to every tissue. A haemoglobin test tells you whether you have enough circulating iron to support oxygen transport right now. A ferritin test tells you whether your reserves are adequate.

This distinction matters because ferritin can drop to critically low levels while haemoglobin remains within the normal range. You can be symptomatic — fatigued, unable to concentrate, losing hair — long before your GP would diagnose iron-deficiency anaemia from a standard full blood count. Iron contributes to the reduction of tiredness and fatigue, contributes to normal oxygen transport in the body, and contributes to normal cognitive function — all authorised EU health claims that reflect how central iron is to everyday function.

If you suspect your ferritin is low, a blood test is the only way to confirm it. Do not supplement iron at high doses without knowing your levels first.

What are the symptoms of low ferritin?

The symptoms of low ferritin overlap significantly with many other conditions, which is why they are so frequently missed or attributed to stress, poor sleep, or "just getting older." Common symptoms include:

Persistent tiredness that is not resolved by rest
Difficulty concentrating and poor short-term memory
Hair thinning or increased hair loss
Breathlessness on exertion — especially during activities that previously felt comfortable
Restless legs — an urge to move the legs, particularly at night
Poor exercise tolerance — declining performance or slower recovery
Frequent infections — iron contributes to the normal function of the immune system

These symptoms can appear gradually, making them easy to normalise. Many people live with low ferritin for months or years without connecting the dots.

The critical point: these symptoms overlap with thyroid disorders, vitamin B12 deficiency, vitamin D deficiency, depression and other conditions. Blood work is essential. Speak to your GP if these symptoms persist.

What causes low ferritin levels?

Ferritin drops when iron losses or demands exceed dietary intake over a sustained period. The most common causes include:

Inadequate dietary intake — particularly relevant for those following plant-based diets. Non-haem iron (from plant sources) has a bioavailability of 2-20%, compared with 15-35% for haem iron from animal sources. Vegans and vegetarians are not inevitably deficient, but they need to be more deliberate about iron-rich food choices and absorption enhancers.

Menstrual blood loss — the most common cause of low ferritin in premenopausal women. Women with heavy periods can lose 5-6 times more iron per cycle than those with lighter flow, creating a chronic deficit that diet alone may not correct.

Pregnancy — iron requirements increase substantially during pregnancy, particularly in the second and third trimesters, to support increased blood volume and foetal development.

Intense exercise — endurance athletes, particularly runners, face a specific risk from foot-strike haemolysis (mechanical destruction of red blood cells), exercise-induced inflammation that raises hepcidin (a hormone that blocks iron absorption), and iron losses through sweat. For more on this, see our guide to vitamins for runners.

GI conditions — coeliac disease, inflammatory bowel disease, and other conditions affecting the gut lining can significantly reduce iron absorption, even when dietary intake is adequate.

Frequent blood donation — each donation removes approximately 200-250mg of iron. Regular donors, particularly women, can deplete ferritin rapidly without supplementation.

How common is iron deficiency in the UK?

More common than most people realise — and it is a population-level problem, not a niche concern.

The National Diet and Nutrition Survey (NDNS) provides the most comprehensive picture of iron status across the UK population. The data is stark:

49% of girls aged 11-18 have iron intakes below the Lower Reference Nutrient Intake (LRNI) — the level below which deficiency is likely
25% of women aged 19-64 fall below the LRNI for iron

A secondary analysis of NDNS data by Derbyshire (2018) confirmed that UK females and younger adults are particularly vulnerable to multiple simultaneous micronutrient shortfalls, with iron consistently among the most concerning gaps.

These numbers mean that a substantial proportion of the UK population — particularly women of reproductive age — are walking around with depleted iron stores and the symptoms that follow.

Which foods are highest in iron?

Dietary iron comes in two forms: haem iron (from animal sources) and non-haem iron (from plant sources). The distinction matters because they are absorbed through different mechanisms, and the difference in bioavailability is significant.

Haem iron — found in red meat, liver, shellfish, poultry and fish — is absorbed at a rate of 15-35%, largely unaffected by other dietary factors.

Non-haem iron — found in lentils, chickpeas, beans, tofu, spinach, fortified cereals and dark leafy greens — is absorbed at a rate of 2-20%, and is heavily influenced by what else you eat at the same meal.

Food	Iron per 100g	Type	Approximate absorption
Liver (chicken)	11mg	Haem	15-35%
Cockles	28mg	Haem	15-35%
Red meat (beef)	3.5mg	Haem	15-35%
Sardines	2.9mg	Haem	15-35%
Lentils (cooked)	3.3mg	Non-haem	2-20%
Chickpeas (cooked)	2.9mg	Non-haem	2-20%
Tofu (firm)	5.4mg	Non-haem	2-20%
Spinach (cooked)	3.6mg	Non-haem	2-20%
Fortified cereals	8-12mg	Non-haem	2-20%
Kidney beans (cooked)	2.5mg	Non-haem	2-20%

For those following vegan or vegetarian diets, this table illustrates why intentional food pairing — particularly with vitamin C — is so important for maximising iron uptake from plant sources.

How does vitamin C increase iron absorption?

Vitamin C contributes to normal iron absorption — an authorised EU health claim.

The mechanism is well established. Vitamin C (ascorbic acid) works in two ways: it reduces ferric iron (Fe³⁺) to the more absorbable ferrous form (Fe²⁺), and it chelates iron in the gut to prevent it forming insoluble compounds with phytates, tannins and other inhibitors.

Hallberg et al. (1989) demonstrated that vitamin C significantly increases non-haem iron absorption when consumed at the same meal. The effect is dose-dependent, with around 50mg of vitamin C providing an optimal effect — roughly the amount in a medium orange or a serving of red pepper.

Practical advice: if you are trying to raise ferritin through diet, pair iron-rich plant foods with a source of vitamin C. Lentil soup with tomatoes, spinach salad with lemon dressing, fortified cereal with strawberries — these combinations meaningfully increase the amount of iron your body actually absorbs.

PARTICULAR includes vitamin C in its formulas partly for this reason — to support the absorption of the iron included in personalised blends.

Which iron supplement form is best for raising ferritin?

The three most common oral iron supplement forms are all ferrous (Fe²⁺) salts, and they differ more in tolerability than in absorption efficiency.

Ferrous sulfate is the most widely prescribed form on the NHS. It is effective, inexpensive, and well-studied. However, it carries the highest rate of gastrointestinal side effects — nausea, constipation, stomach cramps — which are the primary reason people stop taking iron before their stores recover.

Ferrous gluconate is the form PARTICULAR uses. It offers a comparable absorption profile to ferrous sulfate but with better tolerability. A supplement only works if you take it consistently, and tolerability is the single biggest determinant of adherence.

Ferrous fumarate has the highest elemental iron content by weight (33%), making it useful when higher doses are required. It falls somewhere between sulfate and gluconate for side effects.

The clinical evidence for iron supplementation in raising ferritin — even in non-anaemic individuals — is strong. Verdon et al. (2003) conducted a double-blind, placebo-controlled trial in 144 non-anaemic women with unexplained fatigue. Those receiving iron showed a 29% reduction in fatigue scores, with the strongest benefit in women whose ferritin was below 50 mcg/L. Vaucher et al. (2012) replicated this in 198 non-anaemic menstruating women, finding that 12 weeks of iron supplementation decreased fatigue by almost 50% from baseline.

For a detailed comparison of iron supplement forms and absorption factors, see our guide to iron supplements: forms, absorption and how to choose.

How long does it take to increase ferritin levels?

This is one of the most common questions, and the answer requires patience. Replenishing depleted iron stores is not a quick process.

Haemoglobin may begin to improve within 2-4 weeks of consistent supplementation, as new red blood cells are produced with adequate iron. This is why some people feel a difference relatively quickly.

Ferritin, however, takes considerably longer — typically 3-6 months of consistent supplementation to move from depleted to adequate levels. The body prioritises haemoglobin production over rebuilding storage reserves, so ferritin is the last marker to recover.

This timeline assumes consistent daily supplementation with an absorbable form, adequate vitamin C intake, and no ongoing losses (such as heavy menstrual bleeding or GI malabsorption) that outpace intake.

The implication is straightforward: check your ferritin with your GP before starting supplementation, and retest after 3-4 months to assess progress. Do not assume the job is done after a few weeks of feeling better.

Can you take too much iron?

Yes, and this is an important distinction between iron and most other micronutrients. The body has no active excretion mechanism for iron. Unlike water-soluble vitamins, which are excreted through urine when consumed in excess, iron accumulates — primarily in the liver, heart and pancreas.

Excess iron is harmful. It generates reactive oxygen species through Fenton chemistry, causing oxidative damage to tissues. Acute iron toxicity from accidental overdose is a medical emergency, particularly in children.

There is also a genetic dimension. Hereditary haemochromatosis — a condition causing excessive iron absorption — affects approximately 1 in 200 people of Northern European descent. Many are undiagnosed. For these individuals, iron supplementation without prior testing could accelerate iron overload.

This is precisely why testing before high-dose supplementation matters. It is also why PARTICULAR caps iron at 14mg based on individual questionnaire risk factors — well within safe supplemental ranges and calibrated to need rather than a blanket high dose.

How does PARTICULAR approach iron supplementation?

PARTICULAR's questionnaire captures the factors that determine individual iron requirements: dietary pattern, menstrual status, exercise level, life stage and other relevant variables.

Based on these inputs, iron dosing is personalised between 4-14mg of ferrous gluconate — a range that addresses the gap between dietary intake and requirements without pushing into unnecessarily high territory.

The formulation is designed to work as a system:

Iron (ferrous gluconate) — chosen for its balance of absorption efficiency and tolerability
Vitamin C (L-ascorbic acid) — contributes to normal iron absorption, included to support the uptake of iron in the formula
Copper (copper di-D-gluconate) — contributes to normal iron transport in the body, an authorised EU health claim reflecting copper's role in mobilising iron from stores into circulation
Vitamin B12 and folate — both contribute to normal red blood cell formation, supporting the downstream use of absorbed iron

This is not a scattergun multivitamin approach. Each nutrient is included because it plays a specific, evidence-based role in iron metabolism or red blood cell production — and each dose is tailored to the individual.

If you are experiencing symptoms consistent with low ferritin, the first step is always a blood test through your GP. If your results confirm low iron stores, take the questionnaire to see how PARTICULAR can support your intake alongside dietary changes.

Key takeaways

Ferritin is your body's iron reserve. It can be depleted long before anaemia shows on a standard blood test, causing fatigue, hair loss, poor concentration and reduced exercise tolerance.
Low ferritin is common in the UK — 49% of girls aged 11-18 and 25% of women aged 19-64 have iron intakes below the LRNI.
Plant-based diets require more attention to iron because non-haem iron is absorbed at a fraction of the rate of haem iron (2-20% vs 15-35%).
Vitamin C contributes to normal iron absorption. Pairing iron-rich foods with vitamin C sources meaningfully increases uptake.
Ferrous gluconate offers comparable absorption to ferrous sulfate with better tolerability — the form PARTICULAR uses.
Replenishing ferritin takes 3-6 months of consistent supplementation. Haemoglobin improves faster, but storage reserves take time to rebuild.
Iron is unusual among minerals — the body has no active excretion mechanism. Always test before supplementing at high doses, and consult your GP if symptoms persist.
PARTICULAR personalises iron dosing (4-14mg) based on individual risk factors, and includes vitamin C, copper, B12 and folate to support absorption, transport and red blood cell formation.
If you are experiencing persistent tiredness and fatigue, start with a GP blood test — then address the gap with targeted nutrition.

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