Selenomethionine: Uses, Dosing, Side Effects, and Safety
Selenomethionine is a dietary supplement that provides selenium, an essential mineral needed for thyroid function and other normal body processes. It is mainly used to prevent or correct selenium deficiency, including in people with diets that do not provide enough selenium.
Selenomethionine can help maintain normal selenium levels, but more is not always better. Take only the amount on the product label or recommended by a healthcare professional, because excessive selenium can cause harmful effects.
Key facts at a glance
- ATC
- unclassified
- RxNorm
- unknown
- Generic
- Selenomethionine
- Class
- unclassified
- Brands
- —
- Availability
- otc
- Pregnancy
- A
- Lactation
- safe
- Half-life (h)
- 100
- Onset (min)
- 0
- Duration (h)
- 0
- Routes
- oral
- Forms
- capsule, tablet, softgel, powder
- Regions
- United States, Canada, United Kingdom, Australia, Germany, Japan, many other countries
- Monitoring
- selenium levels in blood, thyroid function tests, liver enzymes
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Official drug label
WellAlly may earn a referral fee from linked resources at no extra cost to you. Editorial content is never influenced by commercial relationships.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 27, 2026. · Read our editorial policy