Selenium (Selenomethionine)

Mineral

Also known as: L-selenomethionine, Organic selenium

Grade A

💊 100-200 mcg daily🎯 3 primary uses🔗 3 synergies⚠️ Review warnings

Overview

Highly bioavailable organic selenium for thyroid and antioxidant function. Narrow optimal range requires careful dosing.

Primary Uses

Thyroid supportGlutathione systemImmune function

Frequently Asked About Selenium (Selenomethionine)

How much Selenium (Selenomethionine) should I take?

The typical effective range is 100-200 mcg daily. Individual needs vary based on age, body weight, diet, and goals — start at the lower end and adjust based on response. Always consult a healthcare provider before starting a new supplement.

When is the best time to take Selenium (Selenomethionine)?

Any. Consistency matters more than perfect timing — pick a daily anchor (e.g. with breakfast or before bed) and stick with it.

Should I take Selenium (Selenomethionine) with food?

Optional.

Does Selenium (Selenomethionine) interact with medications?

Yes — known interactions include May enhance blood thinners. If you take any prescription medication, talk to your doctor or pharmacist before starting Selenium (Selenomethionine).

What does Selenium (Selenomethionine) pair well with?

Selenium (Selenomethionine) stacks well with Iodine, Vitamin E, and Zinc — these combinations either improve absorption or work synergistically toward common goals.

Who should not take Selenium (Selenomethionine)?

Selenium (Selenomethionine) should be avoided or used with caution by people with High selenium status. Pregnant or breastfeeding women should consult a healthcare provider before use.

What are the side effects of Selenium (Selenomethionine)?

Most people tolerate Selenium (Selenomethionine) well. The most commonly reported side effects are Garlic breath at high doses. Side effects are usually dose-dependent — lowering the dose often resolves them.

Dosage

Typical range

100-200 mcg daily

Timing

Any

With food

Optional

Duration

Don't exceed 400 mcg

Special Populations

Thyroid patients

Research & Studies

Search the literature now

We haven’t curated landmark studies for Selenium (Selenomethionine)yet — one-click into the primary literature here. PubMed (RCTs) is usually the highest-signal starting point.

Search Selenium (Selenomethionine) research

PubMed (RCTs) ↗Randomized trials PubMed (all) ↗Full literature Cochrane Reviews ↗Systematic reviews Examine.com ↗Research summaries

Browse all curated studies →

Mechanism of Action

• Incorporated into selenoproteins
• Essential for T4 to T3 conversion
• Supports glutathione peroxidase

Evidence Quality

Evidence Grade A

Well-established for thyroid and antioxidant

Safety & Contraindications

Serious Warnings

• Toxicity >400 mcg
• Selenosis

Contraindications

• High selenium status

Common Side Effects

• Garlic breath at high doses

Pregnancy & Breastfeeding

Consult healthcare provider

Liver & Kidney Notes

Safe at normal doses

Interactions

💊 Medications

• May enhance blood thinners

🧪 Supplements

• Works with iodine
• Supports vitamin E

🍽️ Food & Alcohol

• Brazil nuts very high

Stacking & Synergies

Pairs Well With

Iodine ↗Vitamin E ↗Zinc ↗

Avoid Combining With

High-dose C may reduce absorption

Best Goal Synergies

ThyroidAntioxidant

Buying Guide

What to Look For

• Selenomethionine form

Standardization Markers

mcg content

Adulteration risk

Low

Practical Notes

• Narrow optimal range
• One Brazil nut = 70-90 mcg

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Last reviewed: August 2026 by the Formulate Research Team. Sources cited above; methodology and scoring criteria published here.

Cite this page

Formulate Research Team. (2026, August). Selenium (Selenomethionine) — Evidence-Based Supplement Guide. Formulate Supplement Encyclopedia. https://app.formulate-health.app/learning/supplements/selenium-selenomethionine

Educational content based on published research and our scoring methodology. Not medical advice — consult a qualified healthcare provider before starting, stopping, or changing supplements, especially if you take medications, are pregnant, or have a medical condition.

Formulate Research Team. (2026, August). Selenium (Selenomethionine) — Evidence-Based Supplement Guide. Formulate Supplement Encyclopedia. https://app.formulate-health.app/learning/supplements/selenium-selenomethionine