Selenium status and supplementation in thyroid disorders: A narrative review of current evidence.

2025-12
Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS) 92
- Ye Htut Linn
- Sohail Aziz
- Shiueh Lian Mok

PubMed: 41206976
DOI: 10.1016/j.jtemb.2025.127799

Study Design

Type: Review

Selenium (Se), an essential trace element, plays a pivotal role in thyroid hormone synthesis and antioxidant defence mechanisms. This narrative review comprehensively examines the current evidence on Se status and supplementation in various thyroid disorders. Numerous studies indicate that Se deficiency may contribute to the development and progression of thyroid diseases, particularly autoimmune conditions such as Graves' disease (GD), Graves' orbitopathy (GO), and autoimmune thyroiditis (AIT), including Hashimoto's thyroiditis (HT). In GD and GO, Se supplementation, especially when combined with methimazole, has been shown to enhance hormone normalization and antioxidant capacity, although results vary across studies. In AIT and HT, consistent reductions in thyroid autoantibodies and inflammatory markers have been observed following Se supplementation, particularly with selenomethionine. However, the evidence remains inconsistent regarding Se's impact on hypothyroidism, pregnancy-related thyroid dysfunction, goitre, and thyroid cancer. Supplementation of Se has been associated with improvements in quality of life in some thyroid disorders such as GD, GO and HT with subclinical hypothyroidism. While some studies suggest a potential protective or modulatory role, findings vary by geographic region, baseline Se status, and study designs. Excessive intake of Se may also carry risks of toxicity (selenosis) and should be approached with caution. In conclusion, Se supplementation offers potential therapeutic benefits, particularly in autoimmune thyroid diseases. However, further well-designed randomized-controlled trials are necessary to define the optimal form, dose, and duration of supplementation and to clarify its role across diverse thyroid conditions.

Research Insights

L-Selenomethionine→Reduced Inflammatory Markers
In AIT and HT, consistent reductions in thyroid autoantibodies and inflammatory markers have been observed following Se supplementation, particularly with selenomethionine.
Effect
Beneficial
Effect size
Moderate
Dose
not specified
L-Selenomethionine→Reduced Thyroid Autoantibody Level
In AIT and HT, consistent reductions in thyroid autoantibodies and inflammatory markers have been observed following Se supplementation, particularly with selenomethionine.
Effect
Beneficial
Effect size
Moderate
Dose
not specified
Selenium→Enhanced Hormone Normalization
In GD and GO, Se supplementation, especially when combined with methimazole, has been shown to enhance hormone normalization and antioxidant capacity, although results vary across studies.
Effect
Beneficial
Effect size
Moderate
Dose
not specified
Selenium→Improved Antioxidant Capacity
In GD and GO, Se supplementation, especially when combined with methimazole, has been shown to enhance hormone normalization and antioxidant capacity, although results vary across studies.
Effect
Beneficial
Effect size
Moderate
Dose
not specified
Selenium→Improved Quality of Life
Supplementation of Se has been associated with improvements in quality of life in some thyroid disorders such as GD, GO and HT with subclinical hypothyroidism.
Effect
Beneficial
Effect size
Small
Dose
not specified

Adverse Events Reported

Selenium→selenosis
Excessive intake of Se may also carry risks of toxicity (selenosis) and should be approached with caution.
Finding
Reported