selenomethionine is the only one to use. it is NOT from yeast, not directly anyway. if it says "from yeast" it can have elemental selenium in it which is detrimental to glutathione stores and can damage the liver with severe toxicity leading to death. selenomethionine can be taken in the 200-800mcg range, depending on the need. 1200mcg being a max therapeutic level for temporary.

200mcg should be enough for daily supps.