Iron
Iron (Ferritin)
A genuine cause of reversible hair shedding in iron-deficient patients — but useless and potentially harmful if your iron stores are normal.
How Iron works — and how well we know it
Iron is essential for the proliferation of hair follicle matrix cells — the most actively dividing cells in the body. Low ferritin (iron stores) is associated with telogen effluvium; its role in AGA specifically is unproven and conflicting (Sinclair 2002 found no association or supplementation benefit; Olsen 2003 found lower ferritin in AGA). Emerging biology points the other way for AGA: DHT drives iron-dependent lipid peroxidation (ferroptosis) in dermal papilla cells, so excess follicular iron may be actively harmful rather than helpful — making the case for supplementing iron-replete AGA patients weaker still. The classic rationale holds only for deficiency: anagen-phase follicles need iron to sustain rapid cell division.
oral
65–325 mg/day elemental iron, depending on formulation. Best taken with vitamin C to enhance absorption. Continue until ferritin > 70 ng/mL.
Available OTC and prescription. Indicated for iron-deficiency anemia. Hair-loss benefit is restricted to patients with low iron stores (typically ferritin < 30–40 ng/mL).
Women with telogen effluvium and confirmed low ferritin. Athletes, vegetarians, and frequent blood donors are higher-risk groups.
Evidence distribution across 2 claims
Why the grade is D. Iron deficiency is a real and reversible cause of hair shedding, particularly in pre-menopausal women. Supplementation reverses the hair issue when ferritin is genuinely low — but there is no benefit in iron-replete individuals, and excess iron is harmful.
Every claim, traced back to its source
We took every major claim made about Iron and matched it to the specific experimental model behind it. Click a claim to see the model, the finding, and our assessment of how much weight it deserves.
2 claims · evidence-by-evidence breakdown
1Open-LabelWeight: ModerateLow ferritin is associated with telogen effluvium and exacerbates AGAReal correlation between low ferritin and hair shedding; replenishment to >70 ng/mL is reasonable in deficient patients.
Multiple observational studies in women with telogen effluvium and AGA, measuring ferritin levels and correlating with shedding/density.
Women with telogen effluvium have lower mean ferritin than controls. Women with AGA and ferritin < 30 ng/mL have worse outcomes than those with higher levels. Supplementation to normalize ferritin correlates with reduced shedding.
The correlation is consistent across studies. Causation in deficient patients is well-established physiologically — matrix cells need iron to divide. The cutoff is debated (30, 40, or 70 ng/mL) but the principle is sound. This is one of the few nutraceutical interventions with a real, mechanistic basis.
- Trost LB, Bergfeld WF, Calogeras E (2006). J Am Acad Dermatol PMID 16635664
- Park SY et al. (2013). Ann Dermatol PMID 24371392
2Open-LabelWeight: HighIron supplementation in non-deficient individuals provides no hair benefit and risks harmIron only helps if you're deficient. Get bloodwork before supplementing.
Long-standing clinical guidance based on iron metabolism, supported by absence of any RCT showing benefit in iron-replete individuals and abundant evidence of harm from iron overload.
Iron supplementation in iron-replete individuals causes constipation, GI distress, and over time can produce ferritin > 200 ng/mL with oxidative tissue damage. There is no documented hair-growth benefit in this population.
Iron is not a 'more is better' nutrient — excess iron is actively harmful. The hair-supplement industry includes iron in formulations sold to people who have no idea what their ferritin level is. This is irresponsible at best.
- Rushton DH (2002). Clin Exp Dermatol PMID 12190640
What's still missing from the science
- Placebo-controlled RCT of iron supplementation specifically for AGA (vs. telogen effluvium).
- Consensus on the ferritin threshold for clinical action.
Our verdict on Iron
Not in our formulary yet
We don't carry this ingredient. We only formulate around actives where the evidence — and the safety profile — is strong enough to recommend with confidence. As the data matures, we may revisit.
Related treatments
How does Iron stack up against its closest peers?
A botanical 5-alpha reductase inhibitor whose only high-quality trials (in BPH) showed no benefit over placebo; the positive AGA data are small and low-quality.
Read the breakdown →One small Malaysian RCT showed a hair-count increase. Never replicated. Used by Nutrafol to justify its tocotrienol content.
Read the breakdown →Correlated with AGA in observational studies. No RCT yet shows that supplementation reverses or slows hair loss.
Read the breakdown →