Sodium Selenite
Sodium Selenite is a tier 2 form of Selenium, used in 531 on-market products and providing 45.7% elemental selenium by weight.
531
on-market products
tier 2
quality tier
45.7%
elemental fraction
Basis: Na2SeO3, anhydrous (standard dietary-supplement/premix form; a pentahydrate at 0.300 also exists -- check specific labels)
Why this tier: Well absorbed but less well retained than organic selenomethionine (organic forms show higher retention than inorganic forms; Fairweather-Tait 2010).
Source: Fairweather-Tait SJ, Collings R, Hurst R. 2010, Am J Clin Nutr 91(5):1484S-1491S, PMID 20200264