Iron Deficiency and Hair Loss — The Underestimated Cause

Why iron is so important for hair

Hair matrix cells — the cells that produce hair — are among the most active cells in the human body. They divide almost continuously. This cell division requires oxygen, and oxygen is transported via hemoglobin (iron-containing).

If the iron stores fall below a critical threshold, the body first shuts down the "unimportant" iron-dependent processes — and this includes the hair matrix cells. Consequence: The anagen phase shortens, more follicles enter the resting phase, and hair loss increases. A classic picture of diffuse telogen effluvium.

Why "ferritin in the normal range" is not enough

The general laboratory reference range for ferritin (often 15–150 ng/ml in women) is statistically broad and comes from population studies. However, this "normal range" includes individuals who have enough iron for basic functions, but too little for healthy hair production.

Thresholds for hair loss

• Ferritin < 30 ng/ml: manifest iron deficiency — almost always hair loss
• Ferritin 30–70 ng/ml: borderline — often the sole or contributing cause in hair loss patients
• Ferritin > 70 ng/ml: target range for healthy hair growth
• Ferritin > 100 ng/ml: optimal, especially with an accompanying androgenetic component

So, if a person hears from their general practitioner that "everything is in the green range" with a ferritin level of 25 ng/ml — that's where the actual deficiency for hair begins.

Which values should be measured

Mandatory values

• Ferritin — the iron storage protein, the most important marker for iron supply
• Serum iron — current iron level in the blood
• Transferrin — iron transport protein
• Transferrin saturation — ratio of bound to free transferrin
• Hemoglobin — lowered in manifest anemia

Useful additions

• Vitamin D (25-OH-D3) — often lowered in parallel
• Vitamin B12 and folic acid — for erythropoiesis
• Thyroid (TSH, fT3, fT4, Anti-TPO) — frequently combined deficiencies
• CRP — inflammatory elevations can falsely elevate ferritin

Why women are particularly at risk

• Menstruation — every cycle depletes iron, especially with heavy menstrual bleeding
• Pregnancy and breastfeeding — iron requirements double or more
• Vegetarian/vegan diet — plant-based iron is absorbed less well than animal-based iron
• Gastrointestinal diseases (celiac disease, irritable bowel, chronic gastritis) reduce iron absorption
• Medications such as proton pump inhibitors reduce iron absorption from food
• Menopause — sometimes worsening due to additional hormonal factors

What iron deficiency-related hair loss looks like

• Diffuse thinning over the entire scalp — no sharply defined areas
• Increased hair loss when brushing, washing, or putting up hair
• Brittle hair that breaks more easily
• Slowed regrowth
• Sometimes combined with brittle nails, fatigue, concentration problems, cold sensitivity, pale skin
• Pull test diffusely moderately to strongly positive
• Trichoscopy: normal hairline, diffuse reduction without scarring

Diagnosis steps

1. Anamnesis: cycle, nutrition, GI symptoms, medications, pregnancies, pre-existing conditions
2. Clinical examination: trichoscopy, pull test, skin paleness, nails
3. Laboratory diagnostics: complete iron panel plus supplementary values
4. If GI cause is suspected: referral for internal medicine clarification
5. For women with heavy periods: gynecological co-treatment

Supplementation — how to do it right?

Oral iron supplementation (standard)

• Active ingredient: iron bisglycinate or ferrous sulfate — both well absorbed
• Dose: 50–100 mg elemental iron per day
• Intake: ON AN EMPTY STOMACH, ideally with vitamin C (significantly improves absorption)
• Distance to: coffee, tea, dairy products (at least 2 hours — these strongly inhibit absorption)
• Duration: at least 3–6 months, longer if necessary — ferritin rises slowly
• Control: laboratory control every 8–12 weeks

For intolerance problems

• Iron bisglycinate often better tolerated than sulfate (fewer GI complaints)
• Take every other day — newer studies show better absorption than daily intake
• Lactoferrin as a gentler alternative for very sensitive stomachs

For severe deficiency or malabsorption

• Iron infusion via internal medicine practice
• Fast effect, good for very low ferritin (< 20 ng/ml)
• One to three infusions bring the depot into the target range in weeks instead of months
• Often the only effective option for malabsorption disorders

What you can do yourself

Nutrition

• Animal iron (heme iron): red meat, liver, dark poultry meat — very well absorbed
• Plant-based iron: lentils, beans, spinach, tofu, dark grains — combined with vitamin C-containing foods
• Vitamin C sources with meals: bell peppers, citrus fruits, berries — double iron absorption
• Avoid with meals: coffee, tea, milk (inhibit iron absorption)

Lifestyle

• For very heavy menstruation, gynecological clarification — sometimes the hormonal situation is the treatable cause
• Take gastrointestinal complaints seriously — chronic diseases reduce iron absorption
• Women who live long-term vegan/vegetarian: plan regular ferritin checks

Realistic expectation — how quickly does the therapy work?

• Month 1–2: iron stores fill up, no visible hair effect
• Month 3: reduced hair loss, pull test better
• Month 6: first visible regrowth (short new hairs)
• Month 9–12: noticeable recovery of hair density
• Month 12–18: complete restoration with consistent treatment

Patience is crucial. Hair follows iron supply with a delay — those who give up after 4 weeks will see no effect.

What does not help

• Iron without proven deficiency — does nothing and can be harmful in excess
• High-dose multivitamins with minimal iron content — therapeutically ineffective
• "Hair capsules" with mega-doses of biotin without iron — marketing
• Supplementation with normal ferritin — iron excess is toxic (ferritin > 200 ng/ml without deficiency is not desired)

Frequently asked questions

My GP says my ferritin is normal. Should I still supplement?

If you have hair loss and your ferritin is below 70 ng/ml — yes, in consultation with a practice experienced in hair medicine. The general "normal range" is often not sufficient for healthy hair production. For values above 70 ng/ml with persistent hair loss, other causes should be clarified.

How quickly do I need to supplement — tablets or infusion?

For ferritin over 30 ng/ml and a healthy gastrointestinal tract: tablets are sufficient, patience is required. For ferritin under 20 ng/ml, malabsorption disorders or intolerance problems: infusion is often the better choice.

Why does my stomach tolerate iron tablets so poorly?

A common problem. Options: switch from sulfate to bisglycinate, take every other day instead of daily, take after meals (slightly less absorption, but better tolerated), for persistent problems: consider infusion.

Can I take too much iron?

Yes. Excess iron can strain the liver and is dangerous in conditions like hemochromatosis. Supplementation always with laboratory controls and a defined endpoint. Self-treatment without values is not recommended.

Do iron deficiency symptoms return?

Yes, usually completely. Fatigue, concentration problems, cold sensitivity, brittle nails, and hair loss improve with adequate supplementation. Sufficiently long treatment duration is important.

Who covers the treatment?

Iron supplementation is usually done by the general practitioner or an internal medicine practice. The hair medicine practice makes the diagnosis in the context of hair loss and can coordinate the supplementation. We work interdisciplinarily — the iron treatment is carried out by the general practitioner, and hair control and possibly supplementary therapies are carried out by us.