Form Comparison

Sodium Selenate vs Sodium Selenite

How sodium selenate and sodium selenite differ in elemental content, absorption, tolerance, and cost.

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Quick verdict. Both are inorganic forms found mainly in multivitamins. Selenate is nearly completely absorbed but largely lost in urine; selenite is about half absorbed but used directly for selenoproteins. Either is an acceptable source inside a multivitamin, and neither is a reason to choose one product over another; for standalone selenium, selenomethionine is better retained.

Side by Side

Sodium Selenate Sodium Selenite
Elemental content 41.8% elemental selenium 45.7% elemental selenium
Absorption High Moderate
How it is absorbed Inorganic form; nearly completely absorbed, but a large share is excreted in urine rather than retained. Inorganic form; about 50% absorbed. Not stored in proteins, but directly available for selenoprotein synthesis.
Typical dose 55-200 mcg daily 55-200 mcg daily
Common uses multivitamins, food fortification multivitamins, parenteral nutrition
Side effects As for other forms at excess doses. As for other forms at excess doses.
Cost Low Low
Also called selenate selenite
Labels in index 13 43

When to Choose Sodium Selenate

Choose sodium selenate when it comes in a multivitamin. It has no standalone advantage. High absorption but poorer retention than organic forms.

Sodium Selenate

Choose sodium selenate when it comes in a multivitamin. It has no standalone advantage.

What to look for: Sodium Selenate named on the Supplement Facts panel, with the amount per serving stated.

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When to Choose Sodium Selenite

Choose sodium selenite when you want selenium for selenoprotein synthesis without building a protein-bound pool. Lower blood selenium per mcg than selenomethionine does not necessarily mean lower selenoprotein activity.

Sodium Selenite

Less absorbed, but it feeds selenoprotein synthesis directly without building a reserve. The form used in the Graves' orbitopathy trial.

What to look for: Usually a prescribed, time-limited course at a defined dose.

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Products on Titrate

In Titrate's index of NIH label data, 13 labels named as selenium products list sodium selenate and 43 list sodium selenite.

Open supplement search

Selenium does not have its own search category yet. Each product above links to its full label in the NIH database.

Related

References

NIH Office of Dietary Supplements. Selenium: Fact Sheet for Health Professionals.

Clark LC, et al. Effects of selenium supplementation for cancer prevention in patients with carcinoma of the skin. A randomized controlled trial. JAMA. 1996;276(24):1957-1963.

Stranges S, et al. Effects of long-term selenium supplementation on the incidence of type 2 diabetes: a randomized trial. Ann Intern Med. 2007;147(4):217-223.

Thomson CD, et al. Brazil nuts: an effective way to improve selenium status. Am J Clin Nutr. 2008;87(2):379-384.

Lippman SM, et al. Effect of selenium and vitamin E on risk of prostate cancer and other cancers: the Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA. 2009;301(1):39-51.

Hurst R, et al. Establishing optimal selenium status: results of a randomized, double-blind, placebo-controlled trial. Am J Clin Nutr. 2010;91(4):923-931.

MacFarquhar JK, et al. Acute selenium toxicity associated with a dietary supplement. Arch Intern Med. 2010;170(3):256-261.

Marcocci C, et al. Selenium and the course of mild Graves' orbitopathy. N Engl J Med. 2011;364(20):1920-1931.