How Do I Know If I Have a Vitamin Deficiency?

Modern diets frequently fall short on essential vitamins and minerals, and the resulting symptoms can be easy to write off as "just being tired" or "just stress."

Common warning signs include persistent fatigue (often linked to low B-vitamins or vitamin D), mood changes (B12 and vitamin D again), skin and hair changes, muscle weakness, and digestive symptoms.

Vitamin D supports bone health and immune function, B12 is essential for nerve function and energy, and vitamin C supports immune health and tissue repair — each with its own distinct deficiency pattern.

The most reliable way to know is a blood test paired with a conversation about your diet and any absorption issues, rather than guessing and self-treating with high-dose supplements, which can cause their own problems.

For most people, correcting a deficiency starts with diet before it starts with a supplement bottle — but that's exactly the kind of thing worth reviewing with your provider rather than deciding on your own.