mineral
Evidence tier: strong
Essential mineral for haemoglobin production and oxygen transport, repletes iron stores in iron deficiency anaemia and reduces associated fatigue
Iron acts in the blood, the muscles and the mitochondria. It is built into haemoglobin (oxygen transport in red cells), myoglobin (oxygen storage in muscle) and iron sulphur clusters in the enzymes that run energy metabolism and DNA synthesis. This is settled biochemistry rather than a hypothesis, and it is the one ingredient in the vault whose mechanism is genuinely proven. The catch cuts both ways: the body has no mechanism for excreting excess iron, only for regulating how much it lets in, which is why overload is a real disease.
Strong, for one thing only: correcting a diagnosed iron deficiency. That narrowness is the whole finding. A Cochrane review cited by the NIH Office of Dietary Supplements found daily supplementation of 9 to 90 mg cut the risk of anaemia in pregnant women at term by 70 percent and iron deficiency at term by 57 percent. That is medical treatment of a diagnosed condition, not wellness. Past it, the evidence thins fast. In iron deficient but non anaemic adults, a systematic review of 18 randomised trials in 1,170 people found iron reduced self reported fatigue but was not associated with any difference in objective measures of physical capacity, including maximal oxygen consumption (PMID 29626044). Subjective fatigue improves; measured performance does not, and even that was in people with a confirmed deficiency. Postpartum, the 2024 Cochrane review found that for oral iron versus placebo, fatigue was not even reported, while oral iron probably increases constipation compared to intravenous iron (PMID 39670550). In anaemia of chronic disease, ODS says iron supplementation remains controversial because it could increase the risk of infection and cardiovascular events and could cause tissue damage. For thyroid function, restless legs, hair loss and brain fog, all of which the seed graded strong, no primary authority grading exists. Safety dominates this ingredient: accidental overdose of iron containing products is a leading cause of fatal poisoning in children under 6 (FDA mandated warning text, 43 recorded US child deaths between 1983 and 2000), haemochromatosis and iron overload are an absolute contraindication affecting roughly 1 in 200 white adults many of whom are undiagnosed, and LiverTox scores iron A[H], a well established cause of liver injury when given in high doses while having little or no adverse effect on the liver at replacement doses. The governing rule: iron is a repletion product, not a vitality product. It needs a ferritin or haemoglobin result, not a symptom checklist.
Recommended daily allowance: men 8 mg, women 19 to 50 18 mg, women 51 and over 8 mg, pregnancy 27 mg, breastfeeding 9 mg, vegetarians 1.8 times more. Tolerable Upper Intake Level 45 mg a day for adults, counting food and supplements together. Iron only supplements commonly contain 65 mg, already over the upper limit for a healthy adult. Doses of 25 mg and above start blocking zinc absorption. Take with food. Treatment doses for diagnosed anaemia deliberately go above the upper limit under a clinician, and that is medicine, not something PlantRx recommends.
Take with vitamin C (enhances absorption). Take on an empty stomach if tolerated, otherwise with a light meal. Avoid taking within 2 hours of calcium, coffee, or tea. Take every other day to reduce GI side effects.
Onset: ~14 days
Safe and often required in pregnancy and lactation, but dosing must be supervised to avoid iron overload. Iron toxicity is a leading cause of supplement poisoning in children, keep out of reach. GI side effects (constipation, nausea) are common; take with food or use bisglycinate form. Interacts with thyroid medication, antacids, and fluoroquinolone antibiotics (separate by 2+ hours).
Pregnancy: caution
Breastfeeding: caution
Not a plant based remedy, iron is an essential mineral. Iron rich plant foods such as nettle leaf and yellow dock root have been used in traditional herbal medicine for centuries to address symptoms of anaemia and fatigue. Iron supplementation should follow confirmed deficiency testing.
Active compounds: elemental iron, ferrous salts, ferric salts
Remedies using Iron · Browse by body system · Check it against what you take
*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.