Sodium selenite

Sodium selenite (CAS 10102-18-8), also known as disodium selenite or disodium selenium trioxide, is an inorganic selenium compound used as a controlled source of bioavailable selenium. It is not assigned an E-number and carries no standard food additive code in the EU, but is regulated as a nutritional source of selenium in feed and supplement applications.

In animal feed and premix production, sodium selenite supplies selenium at trace levels to prevent deficiency-related conditions such as white muscle disease, functioning as a direct selenium donor absorbed via the gastrointestinal tract. In pharmaceutical and nutraceutical formulations, it serves as an antioxidant co-factor supporting selenoprotein synthesis, including glutathione peroxidase activity.

Sodium selenite is available in feed-grade and pharmaceutical-grade specifications, with pharmaceutical material conforming to Ph.Eur. monograph standards. It is subject to REACH registration and EU feed additive regulation (EC) No 1831/2003. Typical supply formats include small drums and fiber containers with strict handling classifications due to selenium toxicity thresholds.