Zinc
Useful for confirmed zinc deficiency. No AGA benefit in zinc-replete adults; mega-doses cause copper deficiency.
How Zinc works — and how well we know it
Zinc is a cofactor for hundreds of metabolic enzymes including those involved in protein synthesis and cell division. It also has weak 5-alpha reductase inhibitory activity in vitro. Severe deficiency causes diffuse alopecia.
oral, topical
8–15 mg/day (RDA range). Supplement doses up to 50 mg/day are common but carry risk of copper deficiency.
Available as a dietary supplement. RDA 8–11 mg/day. Supplement marketing often uses 15–50 mg/day.
Patients with documented zinc deficiency (typically those with malabsorption, prolonged diarrhea, or restrictive diets).
Evidence distribution across 2 claims
Why the grade is D. Deficiency causes hair loss and is correctable. Supplementation in non-deficient adults has no RCT support for AGA. Mega-doses cause copper deficiency.
Every claim, traced back to its source
We took every major claim made about Zinc 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: LowSerum zinc is lower in AGA patients than controls in some studiesModest correlation between low serum zinc and AGA; supplementation in non-deficient patients is not supported.
Case-control comparisons of serum zinc in AGA vs. controls.
Park 2009 (n=312) and similar studies show lower mean serum zinc in AGA patients. Effect size is modest.
The correlation is real but small, and serum zinc is a poor marker of total-body zinc status. Supplementation studies showing benefit in non-deficient AGA patients do not exist.
- Park H et al. (2009). Ann Dermatol PMID 20523773
2Open-LabelWeight: HighMega-dose zinc causes copper deficiencyChronic high-dose zinc (>40 mg/day) causes copper deficiency. Stay within the RDA range.
Multiple case series documenting copper-deficiency myeloneuropathy in patients taking 50–150 mg/day zinc chronically.
Chronic zinc supplementation above ~40 mg/day reliably depletes copper, eventually producing neurological symptoms and anemia.
Real harm at the doses some hair supplements use. The 'more is better' fallacy applied to a tightly homeostatic micronutrient.
- Maret W, Sandstead HH (2006). J Trace Elem Med Biol PMID 16632171
What's still missing from the science
- RCT of zinc supplementation for AGA in non-deficient patients.
- Better assessment tools for total-body zinc status.
Our verdict on Zinc
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 Zinc stack up against its closest peers?
A genuine cause of reversible hair shedding in iron-deficient patients — but useless and potentially harmful if your iron stores are normal.
Read the breakdown →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 →