August 2026 - Seleniumfacts.com

Why selenium important for thyroid hormone metabolism?

Sufficient selenium is essential for normal thyroid hormone synthesis and activation. Furthermore, selenium is important for protection of the thyroid gland against oxidative stress. Note that both selenium deficiency and excessive intake can impair thyroid health [Gorini 2021].

Thyroid gland needs selenium — **Hypothyroidism can alter glucose metabolism and can increase the risk of insulin resistance.**

Several selenium-dependent enzymes catalyze thyroid hormone synthesis and activation. Similarly, selenoenzymes provide antioxidant protection against oxidative damage [Gorini 2021].

Importantly, selenium is incorporated into deiodinases. These enzymes convert the T4 hormone into the biologically active hormone T3. In addition, antioxidant selenoenzymes such as the glutathione peroxidases and the thioredoxin reductases neutralize hydrogen peroxide radicals that are generated during thyroid hormone production [Gorini 2021]. read more

Where is the strongest evidence that selenium supplementation helps a thyroid disorder?

Answer: The strongest evidence is from studies of patients with Graves’ orbitopathy.

What is Graves’ orbitopathy (GO)?

Prof Urban Alehagen, selenium researcher — In 2024, Prof. Urban Alehagen published KiSel-10 study results that showed that combined selenium and Coenzyme Q10 supplementation of elderly individuals low in selenium has beneficial health effects on thyroid hormones.

Answer: GO, also known as thyroid eye disease, is an inflammatory autoimmune disorder. It affects the tissues around the eyes. It causes swelling and discomfort. Most frequently, it affects individuals who have Graves’ disease [Cleveland Clinic 2026].

What does the clinical evidence show about selenium supplementation and Graves’ orbitopathy?

Answer: In 2026, Kostadinov et al examined data from five RCTs including 303 patients with Graves’ Orbitopathy. 165 patients received selenium; 138 received placebo or no selenium. Selenium supplementation resulted in a significant reduction in clinical activity score. However, the meta-analysis showed no significant differences in Quality of Life improvement or in visual function [Kostadinov 2026]. read more

Milestones in early selenium research

1817 Swedish chemist Jöns Jakob Berzelius discovers selenium

1957 Biochemist Klaus Schwarz shows that selenium in microscopic amounts has a vital importance for mammalian health

1969 Professor J.T. Rotruck discovers that selenium has a biochemical role as a component of the antioxidant enzyme glutathione peroxidase

1969 Professors R.J. Shamberger and D.V. Frost report a possible protective effect of selenium against cancer in humans

1973 Professor J.T. Rotruck identifies the enzyme glutathione peroxidase as a selenium-dependent protein

1977 Professor G.N. Schrauzer publishes cancer mortality correlation studies showing an inverse correlation between dietary intakes of selenium and cancer mortality in 27 countries

1988 Professor G.Q Yang summarizes the lessons learned about the selenium-related endemic diseases Keshan disease and Kashin-Beck disease and about the importance of adequate daily selenium intakes

1989 Professor G.G. Duthie publishes evidence for a role of selenium in the prevention of cardiovascular disease

1993 Researcher W.J. Blot publishes the results of the Nutrition Intervention Trials in Linxian, China, showing that supplementation with a combination of selenium and other antioxidants reduces the risk of cancer

1994 Professor G.N. Schrauzer publishes evidence that selenium is important in the maintenance and therapy of HIV-infected patients

1996 Professor Larry Clark publishes the results of a randomized controlled trial – the Nutritional Prevention of Cancer study -- that shows selenium's cancer-protective effects on colon cancer, lung cancer, and prostate cancer

1997 Professor G.F. Combs summarizes the evidence for the protective effects of selenium against cancer

1999 Professor J.E. Oldfield publishes his Selenium World Atlas, mapping areas of selenium deficiency around the world

2000 Researcher O.A. Levander publishes evidence showing an anti-viral effect of selenium

2002 Researcher R. Gärtner shows that supplementation with selenium reduces inflammation in patients with autoimmune thyroiditis

2002 Researcher Margaret Rayman presents the arguments for increasing selenium intakes to realize selenium’s antioxidant and anti-viral and anti-inflammatory effects as well as selenium’s enhancement of immune function and reproductive success.

Month: August 2026

Selenium and Thyroid Disorders and Type 2 Diabetes Reviewed

Why selenium important for thyroid hormone metabolism?

Selenium and Graves’ Orbitopathy

Where is the strongest evidence that selenium supplementation helps a thyroid disorder?

What is Graves’ orbitopathy (GO)?