Home Ingredients SelenoForce® (Selenium-Enriched Yeast — Sabinsa)
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SelenoForce® (Selenium-Enriched Yeast — Sabinsa)

Evidence Level
Strong
2 Clinical Trials
6 Documented Benefits
4/5 Evidence Score

SelenoForce® is Sabinsa's branded selenium-enriched Saccharomyces cerevisiae yeast — a food-form organic selenium supplement where the selenium has been biosynthetically incorporated into the yeast's amino acids (predominantly selenomethionine, the form selenium takes in dietary foods like Brazil nuts and seafood). Selenomethionine is the most bioavailable form of selenium: a Vanderbilt PK study found ~60% absorption vs ~41% for inorganic sodium selenite. The clinical dose is 100-200 mcg/day (elemental selenium equivalent). Selenium is an essential trace element required for ~25 selenoproteins including the glutathione peroxidase family (antioxidant), iodothyronine deiodinases (thyroid T4→T3 conversion), and thioredoxin reductase (redox regulation). RDA: 55 mcg/day; tolerable upper limit: 400 mcg/day. Honest framing: selenium-enriched yeast is a legitimate organic-form upgrade vs inorganic selenite/selenate, but the bioavailability advantage doesn't justify exceeding the 400 mcg/day upper limit — selenium has a narrow therapeutic window and toxicity (selenosis) can occur at chronic doses above 800 mcg/day.

Studied Dose 100-200 mcg/day elemental selenium from SelenoForce. RDA: 55 mcg/day; tolerable upper limit: 400 mcg/day. Most thyroid trials use 200 mcg/day. Cancer prevention research has explored doses up to 200-400 mcg/day. Doses above 400 mcg/day chronically are NOT recommended due to selenosis risk; doses above 800 mcg/day are unsafe long-term.
Active Compound Selenium-enriched Saccharomyces cerevisiae yeast, with selenium biosynthetically incorporated as selenomethionine (typically 60-65% of total selenium content). Remaining selenium present as selenocysteine, methylselenocysteine, and other organic selenoamino acids. Inorganic selenium content typically <2%.

Benefits

Selenomethionine bioavailability advantage

Vanderbilt PK study compared three selenium forms in 88 subjects across three doses (200, 400, 600 mcg). Selenomethionine showed ~60% absorption (measured by urinary excretion) vs ~41% for sodium selenite, with selenium yeast intermediate. Selenomethionine absorption is dose-dependent (more is absorbed at higher doses); inorganic selenite absorption plateaus.

Supported by Trial 1

Thyroid hormone metabolism support

Selenium is essential for iodothyronine deiodinase enzymes (D1, D2, D3) that convert thyroid hormone T4 to active T3. Selenium deficiency impairs T4→T3 conversion and can produce hypothyroid-like symptoms even with adequate iodine. Particularly relevant for autoimmune thyroid conditions (Hashimoto's) where selenium supplementation (200 mcg/day) has been shown to reduce TPO antibody levels in multiple trials.

Supported by Trial 2, Trial 1

Glutathione peroxidase antioxidant activity

Selenium is the active site of glutathione peroxidase enzymes (GPx1-GPx8), which reduce hydrogen peroxide and lipid peroxides — primary cellular antioxidant defense. Marginal selenium deficiency impairs GPx activity even when overt deficiency isn't present. Supplementing to optimal status (≥125 mcg/L plasma) maximizes GPx capacity.

Supported by Trial 2

Immune function support

Selenium is required for proper T-cell and NK-cell function, antibody production, and antiviral immunity. Studies in selenium-deficient populations (parts of China, New Zealand) show supplementation improves immune markers. Severe selenium deficiency in HIV/AIDS patients is associated with worse outcomes; supplementation has shown benefits in this population.

Supported by Trial 2, Trial 1

Food-form organic delivery

Yeast-bound selenomethionine is incorporated into food-protein-equivalent structures rather than being a free inorganic salt. This matches the form selenium takes in the diet (Brazil nuts, seafood, organ meats) and may offer better tolerability and absorption profile, especially for individuals with sensitive stomachs.

Supported by Trial 1, Trial 2

Tissue selenium accumulation

Selenomethionine accumulates in body proteins (because it can substitute for methionine in protein synthesis), creating a tissue reservoir of selenium. Inorganic selenite doesn't accumulate this way. This can be advantageous for maintaining selenium status during periods of low intake, but also means selenium status takes longer to reverse after stopping supplementation.

Supported by Trial 1, Trial 2

Mechanism of action

1

Selenoprotein synthesis

Selenium is incorporated as selenocysteine (Sec, the 21st amino acid) into approximately 25 human selenoproteins via the UGA-Sec recoding mechanism. These include the glutathione peroxidases, thioredoxin reductases, iodothyronine deiodinases, and selenoprotein P. Adequate selenium status is required for full expression of this entire protein family.

2

Antioxidant defense via glutathione peroxidase

Glutathione peroxidase (GPx) uses selenocysteine to catalytically reduce hydrogen peroxide and organic peroxides to water and alcohols, protecting cellular membranes and DNA from oxidative damage. Eight GPx isoforms target different cellular compartments and substrates.

3

Thyroid hormone activation

Type 1 (D1) and Type 2 (D2) deiodinases convert T4 to bioactive T3 — essential for cellular thyroid hormone signaling. Type 3 (D3) deactivates T4 to reverse T3. All three are selenoenzymes; selenium deficiency impairs the full T4-T3-rT3 equilibrium that regulates thyroid hormone action at tissue level.

4

Methylselenol formation (selenomethionine specific)

Selenomethionine is metabolized to methylselenol — a metabolite with preferential cancer-cell apoptosis activity. This metabolic pathway is more active with selenomethionine than with inorganic selenium forms, partially explaining preferential effects of organic selenium in cancer prevention research.

Clinical trials

1
Selenium Bioavailability Comparison

Randomized controlled trial in 88 subjects comparing three selenium forms (selenomethionine, sodium selenite, high-selenium yeast) at three dose levels (200, 400, 600 mcg).

88 subjects

Randomized controlled trial in 88 subjects comparing three selenium forms (selenomethionine, sodium selenite, high-selenium yeast) at three dose levels (200, 400, 600 mcg). 16-week supplementation. Outcome: selenomethionine absorbed ~60% based on urinary excretion vs ~41% for selenite; yeast intermediate. Selenomethionine absorption was dose-dependent (proportional increase with dose); selenite absorption plateaued at higher doses.

2
Hashimoto Thyroiditis Selenium Trials — Multiple

Multiple clinical trials (Gärtner 2002, others) and pooled analyses show 200 mcg/day organic selenium supplementation reduces thyroid peroxidase (TPO) antibody titers in patients with autoimmune thyroiditis.

Clinical population described in trial publication.

Multiple clinical trials (Gärtner 2002, others) and pooled analyses show 200 mcg/day organic selenium supplementation reduces thyroid peroxidase (TPO) antibody titers in patients with autoimmune thyroiditis. Effects emerge over 3-6 months. Symptomatic improvement variable; antibody reduction more consistent than symptomatic benefit.

Side effects and drug interactions

Common Potential side effects

Generally well-tolerated at clinical doses (100-200 mcg/day).
Garlic breath at higher doses (>400 mcg/day) — characteristic selenium-related side effect from dimethylselenide exhalation.
Selenosis at chronic high doses (>800 mcg/day): hair loss, brittle nails, peripheral neuropathy, skin rash, GI distress. Selenium has a narrow therapeutic window.
Yeast-bound form may not be suitable for individuals with Saccharomyces cerevisiae allergy or who avoid yeast for Candida or autoimmune reasons.
Possible increased risk of type 2 diabetes at chronic doses above 200 mcg/day in already selenium-replete populations (suggested in some observational data — SELECT trial signal).

Important Drug interactions

Anticoagulants — selenium has mild antiplatelet effects in vitro; monitor INR with warfarin at higher doses.
Chemotherapy — selenium status during chemotherapy is complex; some agents have additive effects, others may be antagonized; consult oncologist.
Statins — possible interaction reported with selenium + niacin combinations in HDL-raising context (HATS substudy); minimal interaction with selenium alone.
Iodine — selenium and iodine work synergistically in thyroid function; both deficiency states should be corrected together for optimal results.
Pregnancy and lactation — pregnancy RDA is 60 mcg/day; supplementation up to 200 mcg/day generally considered safe; avoid high doses.

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Frequently asked questions about SelenoForce® (Selenium-Enriched Yeast — Sabinsa)

What is SelenoForce?

SelenoForce® is Sabinsa's branded selenium-enriched Saccharomyces cerevisiae yeast — a food-form organic selenium supplement where the selenium has been biosynthetically incorporated into the yeast's amino acids (predominantly selenomethionine, the form selenium takes in dietary foods like Brazil nuts and seafood).

What is SelenoForce used for?

SelenoForce is researched primarily for Antioxidant, Thyroid Health, and Immune Support. Vanderbilt PK study compared three selenium forms in 88 subjects across three doses (200, 400, 600 mcg). Selenomethionine showed ~60% absorption (measured by urinary excretion) vs ~41% for sodium selenite, with selenium yeast intermediate.

What is the recommended dosage of SelenoForce?

The clinically studied dose is 100-200 mcg/day elemental selenium from SelenoForce. RDA: 55 mcg/day; tolerable upper limit: 400 mcg/day. Most thyroid trials use 200 mcg/day. Cancer prevention research has explored doses up to 200-400 mcg/day. Always follow the product label and check with a healthcare provider for personal advice.

Is SelenoForce safe, and does it have side effects?

For most healthy adults, SelenoForce is well tolerated at studied doses. Reported effects can include: Generally well-tolerated at clinical doses (100-200 mcg/day). Garlic breath at higher doses (>400 mcg/day) — characteristic selenium-related side effect from dimethylselenide exhalation. It may also interact with some medications. SelenoForce is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does SelenoForce interact with any medications?

Possible interactions include: Anticoagulants — selenium has mild antiplatelet effects in vitro; monitor INR with warfarin at higher doses. Chemotherapy — selenium status during chemotherapy is complex; some agents have additive effects, others may be antagonized; consult oncologist. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for SelenoForce?

NutraSmarts rates the evidence for SelenoForce as Strong (4 out of 5). It is backed by 2 clinical trials and 4 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(4 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Peretz A, Neve J, Desmedt J, Duchateau J, Dramaix M, Famaey JP. Lymphocyte response is enhanced by supplementation of elderly subjects with selenium-enriched yeast. Am J Clin Nutr. 1991;53(5):1323-8. doi: 10.1093/ajcn/53.5.1323.PubMedUsed to support: Small placebo-controlled trial in elderly adults where 100 mcg/day selenium-enriched yeast for 6 months significantly raised lymphocyte proliferative response to mitogen, backing the immune-support claim for organic selenium.
  2. Mahmoudi L, Mobasseri M, Ostadrahimi A, Pourmoradian S, Soleimanzadeh H, Kafili B. Effect of Selenium-Enriched Yeast Supplementation on Serum Thyroid-Stimulating Hormone and Anti-Thyroid Peroxidase Antibody Levels in Subclinical Hypothyroidism: Randomized Controlled Trial. Adv Biomed Res. 2021;10:33. doi: 10.4103/abr.abr_252_20.PubMedUsed to support: Small double-blind RCT (42 patients, 200 mcg/day selenium-enriched yeast for 8 weeks) found NO significant effect on TSH or anti-TPO antibodies, tempering the thyroid claim and showing selenium-yeast benefit for subclinical hypothyroidism is unproven.
  3. Anastasilakis AD, Toulis KA, Nisianakis P, Goulis DG, Kampas L, Valeri RM, et al. Selenomethionine treatment in patients with autoimmune thyroiditis: a prospective, quasi-randomised trial. Int J Clin Pract. 2012;66(4):378-83. doi: 10.1111/j.1742-1241.2011.02879.x.PubMedUsed to support: Quasi-randomised trial of selenomethionine in autoimmune thyroiditis with mixed results: anti-thyroglobulin antibodies fell but anti-TPO antibodies and thyroid function did not change significantly, supporting only a partial/uncertain thyroid-autoimmunity benefit.
  4. Kiremidjian-Schumacher L, Roy M, Wishe HI, Cohen MW, Stotzky G. Supplementation with selenium and human immune cell functions. II. Effect on cytotoxic lymphocytes and natural killer cells. Biol Trace Elem Res. 1994;41(1-2):115-27. doi: 10.1007/BF02917222.PubMedUsed to support: Small human trial (200 mcg/day selenium as selenite, not yeast) showing large increases in cytotoxic-lymphocyte and natural-killer-cell tumour-cell killing, backing the immune-support claim though using inorganic selenium rather than the selenomethionine form in SelenoForce.