---
title: "What vitamin deficiency causes hair loss? Key labs"
description: "Iron deficiency is most linked to hair shedding; low vitamin D, zinc, and B12 may contribute. Labs can help identify causes to discuss with a clinician."
canonical: "https://www.vitalsvault.com/treatment-learn/what-deficiency-causes-hair-loss"
last-updated: 2026-08-22
---

# What vitamin deficiency causes hair loss? Key labs

> Iron deficiency is most linked to hair shedding; low vitamin D, zinc, and B12 may contribute. Labs can help identify causes to discuss with a clinician.

---

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