Zinc, Vitamin D & Iron
Also known as micronutrients, ferritin, vitamin D deficiency
Correcting a real deficiency helps a great deal. Supplementing without one does nothing — test, do not guess.
Blood panel $50–150. Supplements $10–30/month.
How it works
Zinc is a cofactor in keratin synthesis and has antibacterial and anti-inflammatory activity relevant to acne. Vitamin D receptors are present in hair follicle keratinocytes and low levels associate with several forms of hair loss. Low ferritin is a well-documented and frequently missed cause of diffuse hair shedding, particularly in menstruating women.
How it's used
Get bloods before supplementing: ferritin, vitamin D, zinc and thyroid function are the useful panel for unexplained hair shedding. Ferritin below roughly 30 ng/mL is commonly implicated in shedding even when haemoglobin is normal, so do not accept a "normal" full blood count as the end of the investigation. Correct deficiencies to target rather than megadosing.
Trade-offs
In favour
- Correcting genuine deficiency can fully resolve diffuse shedding
- Cheap to test and cheap to correct
- Zinc has modest but real evidence in acne
- Addresses a cause rather than masking a symptom
Against
- No benefit whatsoever without an actual deficiency
- Requires blood tests to do properly
- Hair regrowth after correction is slow
Risks and side effects
- Zinc toxicity and copper depletion with prolonged high-dose supplementation
- Iron overload is dangerous — never supplement iron without a documented deficiency
- Vitamin D toxicity at very high sustained doses
- Self-treating masks underlying causes such as thyroid disease or coeliac disease
How good is the evidence?
Strong evidence for deficiency-related hair loss and its correction. Evidence for supplementation in replete individuals is essentially negative.
Sources
Sources point to guideline bodies and literature searches rather than single papers, so they stay accurate as the evidence moves.