Nutrients system

Selenium

Se

A trace mineral essential to thyroid function and antioxidant defense.

What is it

Selenium — in plain English.

Selenium is a trace mineral that serves as a cofactor for several antioxidant enzymes and is essential to thyroid hormone metabolism.

Why it's measured

What Se can reveal.

Selenium status has been studied in research on thyroid function, antioxidant defense, and immune health.

Reference range

Where most laboratories draw the standard line.

Standard laboratory reference

70 – 150 μg/L

Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.

What results may indicate

Higher vs. lower Se — at a high level.

Elevated

High levels can be associated with toxicity in research literature, typically from over-supplementation.

Lower

Has been associated with thyroid dysfunction and certain cardiomyopathies in research literature.

These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.

When it's measured

When Se is typically run.

Measured in comprehensive nutrient panels.

Related markers

Often measured alongside Se.

Measured in

Se is one of 160 biomarkers in the Apex Panel.

A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.

Explore the Apex Panel
160 biomarkers13 body systemsPhysician-reviewed
Back to all biomarkers

This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.