Overview
Organic selenium form — preferred for thyroid (Hashimoto's) and antioxidant support.
- Whole foods (leafy greens, legumes, nuts, seeds, seafood, animal proteins)
- Fortified foods such as cereals, breads, plant milks, and table salt
- Mineral supplements as chelates, citrates, glycinates, or inorganic salts
- Chelated form (glycinate, bisglycinate, citrate, malate)
- Inorganic salt (oxide, sulfate, chloride)
- Liquid ionic solution
- Topical or transdermal preparation
Forms & variants of Selenium
Different chemical forms of Selenium behave differently. Browse each form's mechanism, bioavailability, and best-use context.
Mechanism of action
Substitutes for methionine in proteins; releases Se for selenoprotein synthesis (GPx, deiodinases).
- · Glutathione peroxidase
- · Type 1/2 deiodinase
Effects on the body
Organ system effects
Selenomethionine acts on hallmarks of aging including oxidative stress, mitochondrial dysfunction, and senescence signaling.
Evidence-based benefits
Reduces TPO antibody titers in Hashimoto's
Moderate evidencePotential side effects
- · Garlic breath at high dose
- · Selenosis at >400 mcg/d chronically
Drug interactions
Supplement interactions
- NAD+ precursor (NMN or NR)Complementary mitochondrial and sirtuin support.
- Omega-3Lowers inflammation and supports membrane integrity.
No specific avoidances listed.
Dosing & bioavailability
Where to buy
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Third-party testedIndependently verified Selenomethionine — look for USP, NSF, or Informed Sport seals on the label for purity and dose accuracy.Selenomethionine third party tested NSF
CapsulesPre-measured Selenomethionine capsules — easiest for travel and consistent daily dosing without scoops or scales.Selenomethionine capsules
PowderBulk unflavored Selenomethionine powder — best cost-per-gram and flexible dosing for stacking or mixing into drinks.Selenomethionine powder unflavored
Best sellersMost-purchased Selenomethionine products on Amazon — a quick way to see what's reviewed widely before you commit.Selenomethionine best sellerScientific evidence8Show studiesHide studies
Selenium supplementation and Hashimoto's thyroiditis
Toulis KA, et al.
Meta-analysis of selenium in Hashimoto's.
Reduced TPO antibody titers and improved well-being.
PubMed: Selenomethionine — Reduces TPO antibody titers in Hashimoto's
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