Supplement Label Index

Sodium Selenate vs. Sodium Selenite

Among 4,693 on-market selenium products with an identifiable primary form, 14% use Sodium Selenate (657 products) and 11.3% use Sodium Selenite (528).

Sodium SelenateSodium Selenite
Quality tierTier 2Tier 2
Selenium by weight21.4%45.7%
Share of market14%11.3%
On-market products657528
Median declared dose55 elemental mcg
middle half: 20–100
50 elemental mcg
middle half: 19.25–70
Most common brands21st Century, Vitamin World, Nature's WayWonder Laboratories, DC, SmartyPants

Doses are declared per serving in elemental mcg. “By weight” is the share of the ingredient that is the nutrient itself (e.g. elemental magnesium in a magnesium salt).

Why Sodium Selenate is tier 2

Inorganic selenate is well absorbed but, like selenite, less well retained in tissue than organic selenomethionine per general bioavailability literature.

Source: uncertain -- needs review for a direct comparative citation

Why Sodium Selenite is tier 2

Well absorbed (~80%) but less well retained than organic selenomethionine per comparative bioavailability reviews.

Source: Fairweather-Tait SJ et al., selenium bioavailability review, Am J Clin Nutr -- specific comparative % vs selenate not independently re-verified

Tiers summarize published comparative bioavailability or outcome evidence for each form (see methodology). This page describes the market; it is not a recommendation to take either form. Talk to a clinician about what's right for you.

Other selenium comparisons