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Understand Selenium

Selenium

Mineral & electrolyte markers

What the test generally measures, and what to ask about it.

Longetic keeps every lab and record you’ve had organized and easy to find, so your own Selenium values sit together on one chart and you walk into your next appointment prepared.

Summarize with AI
Updated Jul 13, 2026

What is Selenium?

A trace mineral your body needs for thyroid function, reproduction, and protecting cells from damage.

Selenium is a trace mineral that supports thyroid hormone function, reproduction, and the body's antioxidant defenses. Low levels can be associated with inadequate intake and, in areas with selenium-poor soil, with certain deficiency conditions; deficiency is very rare in the United States and Canada. High levels are usually related to excess supplement intake and can be associated with symptoms such as hair or nail changes and digestive upset. Most people meet their needs through a varied diet.

This glossary entry is for informational purposes only and is not a substitute for professional medical advice. Read our Terms of Use.

References

Official source "Selenium - Consumer Fact Sheet" NIH Office of Dietary Supplements. ods.od.nih.gov/factsheets/Selenium-Consumer.

About our sources

Clinical / professional

Medical societies, specialty colleges, and professional associations whose consensus statements reflect clinical practice standards.

Peer-reviewed research

Original research articles and systematic reviews published in indexed journals and verified through PubMed or DOI.

History of updates

Published · Jul 13, 2026
First published; written and independently fact-checked against the cited sources.

Keep your Selenium results together in one place

Upload a lab, and Longetic reads it, explains it, and reminds you when it's time to re-check — so nothing slips between visits.