Yes, I'm glad for you that your root canal pain and heart palps feel better. Ditto the selenomethionine. The SeMC is good for cancer prevention, but selenomethionine is a better choice for thyroid. The two forms can be used together.
The thyroid gland releases very small amounts of biologically active thyroid hormone (triiodothyronine or T3) and larger amounts of an inactive form of thyroid hormone (thyroxine or T4) into the circulation. Most of the biologically active T3 in the circulation and inside cells is created by the removal of one iodine atom from T4 in a reaction catalyzed by selenium-dependent iodothyronine deiodinase enzymes. Three different selenium-dependent iodothyronine deiodinases (types I, II, and III) can both activate and inactivate thyroid hormone by acting on T3, T4, or other thyroid hormone metabolites. Thus, selenium is an essential element for normal development, growth, and metabolism because of its role in the regulation of thyroid hormones (2, 5).
There is a great deal of evidence indicating that selenium supplementation at high levels reduces the incidence of cancer in animals. More than two-thirds of over 100 published studies in 20 different animal models of spontaneous, viral, and chemically induced cancers found that selenium supplementation significantly reduces tumor incidence (22). The evidence indicates that the methylated forms of selenium are the active species against tumors, and these methylated selenium compounds are produced at the greatest amounts with excess selenium intakes (23). The relationships of selenium intake to cancer in humans and selenium status to tumor incidence in animals have been summarized (24).
Selenium supplements are available in several forms. Sodium selenite and sodium selenate are inorganic forms of selenium. Selenate is almost completely absorbed, but a significant amount is excreted in the urine before it can be incorporated into proteins. Selenite is only about 50% absorbed but is better retained than selenate once it is absorbed. Selenomethionine, an organic form of selenium that occurs naturally in foods, is about 90% absorbed(15). Selenomethionine and selenium-enriched yeast, which mainly supply selenomethionine, are also available as supplements. The consumer should be aware that some forms of selenium yeast on the market contain yeast plus mainly inorganic forms of selenium. Both inorganic and organic forms of selenium can be metabolized to selenocysteine by the body and incorporated into selenoenzymes (60).