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Foundational

Selenium · Selenium (selenomethionine)

Trace mineral with a narrow safe range; often oversupplied.

A
Evidence grade
Replicated human RCTs with hard endpoints

Short answer

Don't take standalone 200 μg/day unless you know your levels are low. A multivitamin's 55 μg is enough for most people.

Product and dose overview

Selenium (Selenium (selenomethionine)) is a foundational with evidence grade A, meaning it is well-supported by replicated human trials. We track 4 products containing Selenium. Typical doses range from 0.027 to 0.2 mg per serving. The top-ranked product scores 7.9 out of 10 on our composite scale (dose, evidence, price, testing, transparency). Prices range up to $72.00 per month.

Evidence grade: A Products in database: 4 Category: Foundational

Top Selenium products

ProductBrandDosePrice/mo3rd-party testedScore
Basic Nutrients 2/DayThorne HealthTech0.2 mg$32.00Yes7.9
Advanced NutrientsThorne HealthTech0.1 mg$72.00Yes6.8
Vital Proteins Beauty Boost CapsulesVital Proteins0.07 mg$30.00No6.0
FormatElysium Health0.027 mg$60.00Yes5.9

Scores are editorial judgments, not a scientific standard. See how we score.

What it is

A trace mineral essential for thyroid function and antioxidant enzymes (glutathione peroxidase). One Brazil nut = your daily requirement.

Why people take it

Correcting deficiency important. Over-supplementation linked to increased diabetes risk in the SELECT trial. Selenium status varies wildly by soil geography.

Our verdict

Don't take standalone 200 μg/day unless you know your levels are low. A multivitamin's 55 μg is enough for most people.

Structure & class

Selenomethionine (organic) more bioavailable than sodium selenite.

Mechanism & clinical data

SELECT (2011) showed 200 μg/day increased type 2 diabetes incidence. Correcting deficiency important, over-dosing harmful.

Pharmacokinetics

Days.

Dose & forms

Trial dose
0.05 mg
/ day
Range in trials
0.055 to 0.2 mg
/ day
Common forms
Selenomethionine, Selenium-yeast, Sodium selenite (avoid)

What to watch out for

Narrow safety margin. Don't stack multiple products with selenium.

Where this dose comes from

The trial dose above is our editorial pick from the published human trials for this ingredient. We choose the dose that the best-available studies used on the endpoint most relevant to longevity. The range shows the lowest and highest doses tested in published trials. The landmark studies below are the papers we read to set it. You can click through and check our work.

When new trials publish, our automated sweeps flag them. If a new study materially changes the dose, we update it through editorial review and record the old dose, new dose, and the triggering study in every affected product's recommendation history. The dose is never changed automatically.

Regulatory status

EUFood supplement (limit 300 μg/day)
USDietary supplement (UL 400 μg)
UKFood supplement
CANHP

Timeline

Regulatory events, evidence grade changes, and key research milestones for Selenium, most recent first. Studies link to the paper; regulatory entries name and link the responsible authority.

  • 2025-04 Regulatory single source
    EU Court sharpens the bar for botanical health claims
    A Court of Justice of the European Union ruling in April 2025 further tightened the requirements for how botanical ingredients (herbs, plant extracts) can be marketed with health claims in the EU, effectively removing much of the flexibility of the on-hold list.
  • 2024-06 Regulatory confirmed
    EU report identifies 117 supplement substances as potential health risks
    The HoA Working Group on Food Supplements (26 European countries) published its first report evaluating 117 substances used in food supplements. Of these, 65 were assessed as likely novel foods, 6 were already regulated, 34 had insufficient data, and 12 were prioritized for Article 8 restriction under Regulation (EC) No 1925/2006. The 12 priority substances include ashwagandha, curcumin, melatonin, piperine, St. John's wort, coumarin, p-synephrine, maca, holy basil, Melaleuca, black cohosh, and L-tryptophan. The report drew on 1,500 RASFF alerts reviewed between 2017 and mid-2022.
    Source →
  • 2011 Research milestone
    SELECT 2011
    200 μg selenium/day associated with increased type 2 diabetes risk.
    Source →
  • 2006-12 Regulatory confirmed
    EU Health Claims Regulation adopted
    Regulation (EC) No 1924/2006 laid down harmonised rules for nutrition and health claims made on foods, including supplements. Only claims listed in the EU Register of authorised claims can be used. Rejected botanical claims are held in a separate on-hold list.
    Source →
  • 1997 Regulatory confirmed
    EU introduces the Novel Food Regulation
    Regulation (EC) No 258/97 required any food or food ingredient without a history of consumption in the EU before 15 May 1997 to be authorised before being placed on the market. This is the framework that captures NMN, spermidine as a supplement ingredient, urolithin A, and many other longevity actives.
    Source →

Landmark studies

Found in these products (4)

All products in our catalog that contain Selenium, ranked by our overall score. Ranking is editorial, never paid.

Thorne HealthTech
Basic Nutrients 2/Day
Multi/greens
Ingredients listed
5 ingredients listedlargest listed: Magnesium 20 mg
Price per serving
$1.07$32.00 · 30 servings
Testing
3rd-party listed · no public lab certificate

Multi-ingredient bundle

Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.

Score & research context 7.9/10

Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.

100%
of trial dose
$1.07
per research-dose day, not label serving
0Trial dose2×
Catalog price · Confirm current price with www.thorne.com
Thorne HealthTech
Advanced Nutrients
Multi/greens
Ingredients listed
10 ingredients listedlargest listed: Vitamin C 425 mg
Price per serving
$2.40$72.00 · 30 servings
Testing
3rd-party listed · no public lab certificate

Multi-ingredient bundle

Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.

Score & research context 6.8/10

Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.

100%
of trial dose
$2.82
per research-dose day, not label serving
0Trial dose2×
Catalog price · Confirm current price with www.thorne.com
Vitamin
Ingredients listed
7 ingredients listedlargest listed: Vitamin C 180 mg
Price per serving
$1.00$30.00 · 30 servings
Testing
None listed

Elemental vs compound: check label

Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.

Score & research context 6.0/10

Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.

90%
of trial dose
$2.78
per research-dose day, not label serving
0Trial dose2×
Catalog price · Confirm current price with www.vitalproteins.com
Elysium Health
Format
Antioxidant
Ingredients listed
3 ingredients listedlargest listed: Vitamin C 90 mg
Price per serving
$2.00$60.00 · 30 servings
Testing
3rd-party listed · no public lab certificate

Elemental vs compound: check label

Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.

Score & research context 5.9/10

Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.

45%
of trial dose
$11.11
per research-dose day, not label serving
0Trial dose2×
Catalog price · Confirm current price with www.elysiumhealth.com
Editorial guides

Buying guides and comparisons

Neighbouring molecules

Related ingredients

See all in Foundational →

Molecules in the same class, plus the actives most often formulated alongside Selenium in our catalogue.

Omega-3 (EPA/DHA)Asame categoryVitamin D3Asame categoryVitamin K2Bsame categoryMagnesiumAsame categoryVitamin B12Asame categoryFolate (5-MTHF)Bsame categoryZincAsame categoryVitamin CAsame category
Product shelves
See all in Multi/greens (2)See all in Vitamin (1)See all in Antioxidant (1)

See Selenium in context: the mechanism it acts through, the biomarker it moves, the products that dose it, and the trials that tested it.

View Selenium on the Longevity Map →

Frequently asked questions

What is Selenium?

A trace mineral essential for thyroid function and antioxidant enzymes (glutathione peroxidase). One Brazil nut = your daily requirement.

What dose of Selenium should I take?

The trial dose in published human studies is 0.05 mg per day, with a range of 0.055 to 0.2 mg per day. Always consult a qualified clinician before starting any supplement.

Is Selenium safe?

Narrow safety margin. Don't stack multiple products with selenium.

What is the best Selenium supplement?

We track 4 products containing Selenium. The top-ranked product scores 7.9 out of 10 on our composite scale, which evaluates dose, evidence, price, third-party testing, and transparency. See the comparison table above. Scores are editorial judgments, not a scientific standard.

What is the evidence grade for Selenium?

Selenium has evidence grade A, meaning it is well-supported by replicated human trials. Grade A means replicated human RCTs with hard endpoints. Grade B means human RCTs with biomarker outcomes. Grade C means mixed or small human trials. See our evidence grading methodology.

Independently checked

Data verification

Evidence grade
A
Replicated human RCTs with hard endpoints
Research dose
0.05 mg
Products tracked
4
Updated continuously
Safety signal
Narrow safety margin. Don't stack multiple products with ...

Evidence grades are reviewed when new human RCTs are published. Product counts update automatically as new products are added. Dose ranges reflect published trial data, not brand recommendations. Read how we verify.