How to Choose the Best Selenium Supplement

How to Choose the Best Selenium Supplement

As stated in the previous post, selenium plays an essential role in many processes in the human body, including thyroid metabolism. In another post, we explained which foods are the best sources of selenium that you should introduce into your diet. Today, we would like to discuss when, how, and the best selenium supplements you may need and how to select them.

Do you really need a selenium supplement?

If you are interested in thyroid treatment topic, you should have probably heard of selenium supplements hundreds of times. Despite such popularity, there is a lack of evidence behind its application in endocrinology. In other words, there are very few studies where a selenium supplement was more effective than a placebo in the management of thyroid diseases. Currently, the only condition where an indication of selenium supplement has reliable evidence is Graves’ orbitopathy. This recommendation, for instance, is reflected in the guidelines of the European Thyroid Association/European Group on Graves’ Orbitopathy (EUGOGO). For all other cases, the deficiency of selenium must be detected by the laboratory first in order to state that there is a need in additional natural or synthetic sources of it in your diet. If no clear indication for a supplement is detected, enriching your diet with natural sources of selenium is more beneficial than any pills or capsules. This rule applies to most of the supplements, as nature has balanced out various products so the micronutrients are absorbed and utilized to the maximum. Besides, any supplement is a substance that may bring not only benefits but also some toxicity to your liver, kidneys, and other organs. Thus, we strongly advise you to talk to your doctor before making any decisions, even though you do not need their prescription for selenium supplements.

How to choose the best selenium supplement?

In the case of a confirmed need for an additional selenium, you may face the problem of choosing the suitable form of it. Selenium exists in two forms: inorganic (selenate and selenite) and organic (selenomethionine and selenocysteine), and both of them may serve as a source of selenium. However, organic forms of selenium have been proven to have higher bioavailability levels, thus being better absorbed by the intestines. For instance, the human body absorbs more than 90% of selenomethionine but only about 50% of selenium from selenite. This means that organic selenium is often the best selenium supplement choice.

Even though the FDA recommends 55 mcg of selenium for adults and children aged 4+ years as a daily value (DV), we can’t estimate your need in supplement according to it, as this value is calculated for healthy people with no indications for additional selenium treatment. Also, the DV includes both food and supplements; thus, all dietary sources must be taken into account to avoid an overdose of selenium – selenosis.

However, there is no reason to worry and start the supplement with no indications – most Americans consume adequate amounts of selenium, according to an analysis of data from the 2009–2010 National Health and Nutrition Examination Survey (NHANES). According to an analysis of NHANES data from 2003–2004, the mean serum selenium concentration in U.S. adults aged 40 years or older is 13.67 mcg/dL. Thus, if no medical indications are discovered, there is no need for a selenium supplement “just in case”, as a great variety of products provides us with this important nutrient on a daily basis. Thus, the best selenium supplement is the one you actually need, and that was prescribed by the specialist accordingly to your condition.


At ThyForLife, we do our utmost to provide accurate information. For detailed medical information regarding diagnosis, treatment, and general practices please consult your healthcare professional. Always listen to the advice of your healthcare provider.
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