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Iron (ferrous bisglycinate)

Cochrane evidence supports iron supplementation in iron-deficiency anaemia for fatigue.

Why

Cochrane evidence supports iron supplementation in iron-deficiency anaemia for fatigue. Don't supplement blindly: test ferritin and saturation first.

How it works

Component of haemoglobin; oxygen transport and mitochondrial electron-transport chain function depend on adequate iron stores.

Expected onset · Haemoglobin rise within 2–4 weeks; full repletion of ferritin typically takes 3–6 months

How to take

Dosage

Typical adult treatment: 40–80 mg elemental iron daily or every-other-day (alternate-day dosing now favoured for better absorption). Bisglycinate forms are gentler on the gut. Always test ferritin and transferrin saturation first.

Timing

Morning, on empty stomach, with vitamin C; not with coffee, tea, calcium, or zinc

Safety

Do not supplement without documented deficiency; iron overload causes harm. Avoid in haemochromatosis, thalassaemia traits without specialist guidance. Take 2 h apart from levothyroxine, fluoroquinolones, tetracyclines, and PPIs.

Check interactions with my medications

Evidence

At a glance

Houston 2018 BMJ Open systematic review (4 RCTs, n=714 non-anaemic iron-deficient adults): oral iron reduced self-reported fatigue (SMD -0.38, 95% CI -0.52 to -0.23), but did not improve objective exercise capacity. Stoffel 2017 Lancet Haematol shows alternate-day dosing actually increases fractional absorption vs daily dosing.

Where to get it

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