Selenium
Here’s what it reflects — and what to do about it.
Longetic pulls together every lab and record you’ve had, follows how Selenium changes over time, and explains what’s shifting — so you walk into your next appointment prepared, with reminders for retests along the way.
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.
What to know about Selenium
Understanding Selenium means knowing what it reflects, what tends to move it, and the signs that suggest it’s worth a closer look — so you can bring the right questions to your next appointment.
This glossary entry is for informational purposes only and is not a substitute for professional medical advice. Read our Medical Disclaimer.
References
About our sources
Official sources
Government health agencies, national institutes, and intergovernmental bodies whose guidelines carry regulatory or policy weight.
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.