Mineral
Selenium (as Fermented Selenium Glycinate)
Also known as: Selenium glycinate, Chelated selenium, Organic selenium
Selenium is an essential trace mineral incorporated into selenoproteins that provide antioxidant defense and thyroid hormone metabolism. Glycinate chelation may improve absorption compared to inorganic forms.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Every Selenium (as Fermented Selenium Glycinate) product we have scored
| # | Product | Score | Per serving |
|---|---|---|---|
| 1 | Thorne Selenium | 96 A | $0.23 |
| 2 | Pure Encapsulations Selenium (citrate) | 94 A | $0.22 |
| 3 | Pure Encapsulations Selenium (selenomethionine) | 94 A | $0.24 |
| 4 | Nutricost Selenium Capsules | 94 A | $0.06 |
| 5 | Life Extension Se-Methyl L-Selenocysteine | 94 A | $0.09 |
| 6 | Natural Factors SelenoExcell Selenium | 92 A | $0.15 |
| 7 | Life Extension Super Selenium Complex & Vitamin E | 91 A | $0.10 |
| 8 | Thorne Thyroid Health Complex | 90 A | $0.33 |
| 9 | NOW Foods NAC | 89 A | $0.12 |
| 10 | MegaFood Skin, Nails & Hair 2 | 89 A | $0.87 |
| 11 | Thorne Advanced Nutrients | 88 A | $2.40 |
| 12 | Thorne Basic Nutrients 2/Day | 88 A | $0.60 |
Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.
Common questions
How much Selenium (as Fermented Selenium Glycinate) should I take?
The typical range is 50-200 mcg daily. Ongoing supplementation recommended; upper limit generally 400 mcg/day
When should I take Selenium (as Fermented Selenium Glycinate)?
Consistent daily timing recommended. Can be taken with or without food.
Which form of Selenium (as Fermented Selenium Glycinate) is best?
Selenium glycinate (chelated form).
Is Selenium (as Fermented Selenium Glycinate) safe?
Commonly reported: Garlic odor on breath, Nausea at high doses.
Which Selenium (as Fermented Selenium Glycinate) supplement scores highest?
Thorne Selenium, at 96/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.
Primary uses
- Antioxidant defense
- Thyroid hormone metabolism
- Immune support
- Reproductive health
How it works
- Component of glutathione peroxidase and thioredoxin reductase
- Selenoprotein synthesis
- Thyroid peroxidase cofactor
- Free radical neutralization
Dosage
- Typical range
- 50-200 mcg daily
- Timing
- Consistent daily timing recommended
- With food
- Can be taken with or without food
- Duration
- Ongoing supplementation recommended; upper limit generally 400 mcg/day
- Special populations
- RDA: 55 mcg (adults), 60 mcg (pregnant), 70 mcg (lactating), 20-40 mcg (children). Upper limit: 400 mcg/day to avoid selenosis.
Forms
- Selenium glycinate (chelated form)· 70/100
Safety
Common side effects
- Garlic odor on breath
- Nausea at high doses
Contraindications
- History of selenosis
- Excessive iodine intake combined with high selenium (may worsen thyroid dysfunction)
Products containing Selenium (as Fermented Selenium Glycinate)
Top-scoring supplements in our catalog that list Selenium (as Fermented Selenium Glycinate) on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Evidence notes
Strong RCT evidence supports selenium's role in antioxidant defense and thyroid health. Organic/chelated forms show improved bioavailability in comparison studies.
Grade A: Multiple well-designed human trials support the main claims.
Related in Mineral
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.