Sodium Selenite
Also known as: selenite, Na2SeO3, inorganic selenium, selenium (as sodium selenite)
An inorganic selenium salt that is about 46% selenium by weight, inexpensive, and readily converted to selenide for selenoprotein synthesis. It is absorbed somewhat less completely than selenomethionine and is not stored in general body proteins, so it raises blood selenium less at the same dose, but it is efficient at saturating glutathione peroxidase activity. It is common in budget multivitamins and in animal nutrition. Like all selenium forms it is shipped diluted on a carrier.
Research summary
Reduced to selenide in the body and used directly for selenocysteine synthesis in glutathione peroxidases, thioredoxin reductases, and deiodinases.
Dosage
Daily amounts, elemental (46% of the compound is the element).
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 50 mcg | 50–200 mcg | 400 mcg | 400 mcg |
NIH ODS — UL of 400 mcg/day for adults from all sources
Doses are micrograms of elemental selenium. Sodium selenite (Na2SeO3, MW 172.9) is 45.7% Se: 78.97 ÷ 172.9; the pentahydrate is ≈ 30%. Typically supplied as a 1% trituration, so raw_material_mg_per_dose_unit = 0.1 mg per mcg — adjust to the supplier's premix. Xia 2005 found selenite raised plasma selenium and glutathione peroxidase but produced lower plasma selenium than selenomethionine at equal doses. Capped at the 400 mcg UL. Take with food; selenite has a metallic taste in liquids.
Source material: synthetic (selenium dioxide reacted with sodium hydroxide), supplied as a 0.5–1% dilution
As supplied: Typically supplied as a 1% (10,000 mcg/g) trituration; pure selenite ≈ 46% Se
Forms of Selenium
| Form | Typical dose | Element % | Formats | Price |
|---|---|---|---|---|
| Sodium Selenite | 50–200 mcg | 46% | Capsule, Powder, Tablet, Liquid | low |
| L-Selenomethionine | 50–200 mcg | 40% | Capsule, Powder, Tablet, Gummy, Liquid | low |
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Micro-dose; carrier dilution sets fill weight. Avoid combining loose with high-dose vitamin C in liquid formats, which can reduce selenite to poorly absorbed elemental selenium.
Formulation notes
High-dose vitamin C taken at the same time may reduce absorption of selenite. Vitamin E is a common pairing. Count all selenium sources in the formula toward the UL.
- Has an upper limit
Sources
Related ingredients
Vitamin C (Ascorbic Acid)
VitaminAscorbic acid is the reference form of vitamin C and the most common form in supplements; NIH ODS notes its bioavailability equals that of vitamin C naturally present in food.
Typical: 250–1,000 mg
L-Selenomethionine
MineralThe organic selenium form found in Brazil nuts, grains, and selenium yeast, in which selenium replaces sulfur in the amino acid methionine.
Typical: 50–200 mcg
Greens Blend (Generic)
OtherA generic greens blend is a placeholder for the dried plant powders typical of greens products: cereal grasses such as wheatgrass and barley grass, spirulina and chlorella, leafy vegetables like spinach and kale, and often fruit or vegetable extracts.
Typical: 3–10 g
Spirulina
OtherSpirulina is a dried cyanobacterium (Arthrospira platensis or A.
Typical: 1–5 g
Zinc Citrate
MineralA zinc salt of citric acid with a relatively high zinc content of about 31%, giving it a compactness advantage over gluconate and picolinate.
Typical: 10–25 mg