Table 1. Sources of organic Se available on the market.

Source	Comments	SeMet*	References
Se-yeast	Well researched, 50–70% SeMet	Yes	Schrauzer, 2006
Se-Met	Not stable, >95% SeMet	Yes	Liu et al., 2017
Zn-SeMet	Not stable, >95% SeMet	Yes	Geraert et al., 2015
OH-SeMet	Stable, >95% OH-SeMet	Yes	Liu et al., 2017
Se-proteinates	Chemistry is not proven	No	Liu et al., 2017
Se-glycinates	Chemistry is not proven	No	Liu et al., 2017
Se-chelates	Chemistry is not proven	No	Kubachka et al., 2017
Se-homolanthionine	Lack of research data	No	Anan et al., 2011
Other (nano-Se, etc.)	Lack of data on molecular mechanisms of action	No	Pelyhe and Mezes, 2013; Sarkar et al., 2015

^*As only SeMet can be non-specifically incorporated into proteins in measurable amounts, it is an active component of organic Se sources.