Sodium selenite

Selenium Benefits: Thyroid, Antioxidants & Immune Support

What it is
Sodium selenite is an inorganic form of selenium, an essential trace mineral required for a wide range of physiological functions. Selenium is naturally found in foods such as Brazil nuts, seafood, meats, and grains, though its content can vary depending on soil levels.

In supplements, sodium selenite is commonly used due to its stability and bioavailability, providing a reliable source of selenium to support antioxidant, thyroid, and immune functions [1].

How it works in the body
Selenium is incorporated into a group of specialized proteins known as selenoproteins, which play critical roles in maintaining cellular health. Among these are enzymes such as glutathione peroxidases and thioredoxin reductases, which help protect cells from oxidative damage by neutralizing free radicals [2].

Selenium is also essential for thyroid hormone metabolism, as it is required for enzymes (deiodinases) that convert thyroxine (T4) into its active form, triiodothyronine (T3). This makes selenium important for maintaining normal metabolic function and energy regulation.

In addition, selenium contributes to immune system function, influencing immune cell activity and helping regulate inflammatory responses. Adequate selenium status has been associated with improved immune resilience and protection against oxidative stress-related conditions.

Both deficiency and excess intake can impact health, highlighting the importance of maintaining balanced selenium levels.

Primary benefits
• Supports antioxidant defense and cellular protection
• Supports thyroid hormone metabolism
• Supports immune system function

Typical supplemental range
50–200 µg daily

Safety notes
Excess selenium intake can lead to toxicity (selenosis), with symptoms such as hair loss, brittle nails, and gastrointestinal upset. Intake should remain within recommended ranges.

Did you know?
Selenium is one of the few minerals incorporated directly into proteins as the amino acid selenocysteine, often referred to as the “21st amino acid.”

References

1. Rayman MP. Lancet. 2012

2. Roman M et al. Nutrients. 2014