Home Ingredients Selenium Yeast (High-Selenium Yeast)
AntioxidantImmune Support

Selenium Yeast (High-Selenium Yeast)

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

Selenium yeast is Saccharomyces cerevisiae yeast grown in selenium-enriched media — the yeast incorporates selenium into selenomethionine and other organic selenoamino acids, producing a 'food-form' selenium supplement. The landmark Nutritional Prevention of Cancer (NPC) trial used a standardized selenized yeast — though the later, larger SELECT trial used pure L-selenomethionine, not yeast. Distinct from pure selenomethionine by containing diverse selenoamino acids and yeast-derived nutrients. Well-characterized branded selenium yeasts (e.g., SelenoExcell®, SelenoPrecise®) have their own dedicated profiles.

Studied Dose 100-200 µg elemental selenium/day; SELECT used 200 µg/day; NPC trial used 200 µg/day
Active Compound Selenium yeast (~70-90% selenomethionine + selenocysteine + other selenoamino acids)

Benefits

Used in Major Cancer Trials

Selenized yeast was the form used in the NPC trial (Nutritional Prevention of Cancer, Clark 1996); its primary skin-cancer endpoint was negative, but secondary analyses suggested lower total/prostate cancer in low-selenium men. The later SELECT trial — which used L-selenomethionine, not yeast — found no cancer prevention. Historical/research context; cancer prevention is not established.

Supported by Trial 2, Trial 1

Diverse Selenoamino Acids

Selenium yeast contains selenomethionine (~70-90%) plus selenocysteine, selenocystathionine, methylselenocysteine, and small amounts of inorganic selenite — broader profile than pure selenomethionine. Theoretical advantage of yeast-derived nutritional matrix.

Supported by Trial 1, Trial 2

Food-Form Selenium

Marketed as 'food-form' selenium for those preferring whole-food approaches over isolated nutrients. Yeast-grown nutrients have somewhat better absorption profiles than synthetic forms in some cases.

Supported by Trial 1, Trial 2

Standardization in Branded Forms

Standardized branded selenium yeasts — such as SelenoExcell® (Cypress Systems, used in the NPC trial) and SelenoPrecise® (Pharma Nord, used in the KiSel-10 trial) — have well-characterized selenium speciation and dominate the clinical literature. Generic selenium yeast products vary in standardization. See the dedicated branded profiles for trial details.

Supported by Trial 1, Trial 2

Selenium Deficiency Treatment

Effective for raising plasma selenium and selenoproteins in deficient populations. Comparable to selenomethionine for repletion.

Supported by Trial 1, Trial 2

Mechanism of action

1

Yeast Selenium Speciation

Saccharomyces cerevisiae grown in selenium-enriched media incorporates selenium into amino acids — converting methionine → selenomethionine via the methionine biosynthesis pathway. The resulting yeast contains ~70-90% selenomethionine plus minor selenoamino acids.

2

Broad Selenoprotein Support

Once digested and absorbed, selenium yeast components feed into selenoamino acid pool — supporting synthesis of all >25 selenoproteins (glutathione peroxidases, thioredoxin reductases, iodothyronine deiodinases, selenoprotein P, etc.).

3

Yeast Nutritional Matrix

Whole yeast also provides B vitamins, beta-glucans (immune-modulatory), nucleotides — possibly contributing to broader nutritional effects beyond selenium alone.

4

Slow Selenium Release

Selenium incorporated into yeast proteins is released gradually during digestion — different release kinetics than free selenomethionine or sodium selenite.

Clinical trials

1
SELECT Trial — Selenium (as L-Selenomethionine) for Cancer Prevention (negative)

Large clinical trial (n=35,533) of selenium as L-SELENOMETHIONINE (200 µg/day) — not selenium yeast — and/or vitamin E for prostate cancer prevention in healthy men. (JAMA — and follow-up)

35,533 men.

Important: SELECT used pure L-selenomethionine, not selenized yeast, so it does not directly test selenium yeast. Primary endpoint negative: neither selenium nor vitamin E reduced prostate cancer; vitamin E alone increased prostate cancer risk (~17%); selenium showed a possible T2DM risk signal in subgroups. Tempered enthusiasm for selenium chemoprevention.

2
NPC Trial — Selenized Yeast, Cancer Findings Not Confirmed

Randomized, double-blind, placebo-controlled trial (n=1,312) of selenized yeast (200 µg/day) vs placebo for nonmelanoma skin cancer prevention. Secondary analyses examined other cancers.

1,312 patients with prior nonmelanoma skin cancer.

The primary skin-cancer endpoint was negative — selenium actually increased squamous-cell and total nonmelanoma skin cancer. Exploratory secondary findings suggested lower total/prostate cancer (mainly in low-selenium men), which generated enthusiasm and motivated SELECT. Later trials did not confirm cancer prevention; no cancer-prevention claim is supported.

Side effects and drug interactions

Common Potential side effects

Generally well-tolerated.
Garlic breath, metallic taste at high doses.
GI distress at high doses.
Selenium toxicity (selenosis) at chronic high doses (>800 µg/day).
T2DM risk signal at high chronic doses (SELECT subgroup data) — concerning in selenium-replete populations.
Yeast allergy — rare but possible reactions in those sensitive to S. cerevisiae.

Important Drug interactions

Same as other selenium forms — chemotherapy (consult oncologist), warfarin (theoretical bleeding), levothyroxine (T4-to-T3 modulation).
Yeast-derived components — consider in those with known yeast sensitivities or on yeast-restricted diets.

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Frequently asked questions about Selenium Yeast (High-Selenium Yeast)

What is selenium yeast?

Selenium yeast is yeast grown in a selenium-rich medium so that it incorporates selenium (mostly as selenomethionine) into its proteins. It is a popular food-form selenium used in many studies, including large cancer-prevention trials.

Is selenium yeast a good form?

Yes, it is well absorbed and provides selenium in the natural organic forms found in food, primarily selenomethionine. It was the form used in prominent selenium research, which adds to its popularity.

How much selenium yeast should I take?

It is dosed to provide selenium, with supplements commonly supplying 100 to 200 mcg. The RDA is 55 mcg. Keep total selenium under 400 mcg per day from all sources, as excess is toxic.

Is selenium yeast safe?

At recommended amounts it is safe and well tolerated. As with all selenium, the safe range is narrow, so avoid stacking multiple high-selenium products, and do not exceed 400 mcg per day without medical guidance.

What is Selenium Yeast used for?

Selenium Yeast is researched primarily for Antioxidant and Immune Support. Selenized yeast was the form used in the NPC trial (Nutritional Prevention of Cancer, Clark 1996); its primary skin-cancer endpoint was negative, but secondary analyses suggested lower total/prostate cancer in low-selenium men.

What is the recommended dosage of Selenium Yeast?

The clinically studied dose is 100-200 µg elemental selenium/day; Select used 200 µg/day; NPC trial used 200 µg/day Always follow the product label and check with a healthcare provider for personal advice.

Is Selenium Yeast safe, and does it have side effects?

For most healthy adults, Selenium Yeast is well tolerated at studied doses. Reported effects can include: Generally well-tolerated. Garlic breath, metallic taste at high doses. It may also interact with some medications. Selenium Yeast 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 Selenium Yeast interact with any medications?

Possible interactions include: Same as other selenium forms — chemotherapy (consult oncologist), warfarin (theoretical bleeding), levothyroxine (T4-to-T3 modulation). Yeast-derived components — consider in those with known yeast sensitivities or on yeast-restricted diets. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Selenium Yeast?

NutraSmarts rates the evidence for Selenium Yeast 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. Rayman MP, Searle E, Kelly L, Johnsen S, Bodman-Smith K, Bath SC, et al. Effect of selenium on markers of risk of pre-eclampsia in UK pregnant women: a randomised, controlled pilot trial. The British Journal of Nutrition. 2014;112(1):99-111. doi: 10.1017/S0007114514000531.PubMedUsed to support: Uses Se-enriched yeast to raise selenium status (whole-blood Se, selenoprotein P) in pregnancy. Honest framing: a pilot trial powered for biomarkers, not clinical pre-eclampsia outcomes.
  2. Rayman MP, Winther KH, Pastor-Barriuso R, Cold F, Thvilum M, Stranges S, et al. Effect of long-term selenium supplementation on mortality: Results from a multiple-dose, randomised controlled trial. Free Radical Biology & Medicine. 2018;127:46-54. doi: 10.1016/j.freeradbiomed.2018.02.015.PubMedUsed to support: A multiple-dose RCT of selenium-enriched yeast (100/200/300 ug/day) in a selenium-replete population. Honest framing: it found no mortality benefit and a hint of higher long-term mortality at higher doses, reinforcing that Se-yeast benefits are not guaranteed and may carry risk in replete people.
  3. Rayman MP, Blundell-Pound G, Pastor-Barriuso R, Guallar E, Steinbrenner H, Stranges S A randomized trial of selenium supplementation and risk of type-2 diabetes, as assessed by plasma adiponectin. PLoS One. 2012;7(9):e45269. doi: 10.1371/journal.pone.0045269.PubMedUsed to support: A high-selenium-yeast RCT examining a diabetes-related biomarker (adiponectin). Honest framing: no clear benefit was shown, consistent with concerns that selenium supplementation may not help (and could worsen) glucose metabolism in replete individuals.
  4. Hu Y, McIntosh GH, Le Leu RK, Upton JM, Woodman RJ, Young GP The influence of selenium-enriched milk proteins and selenium yeast on plasma selenium levels and rectal selenoprotein gene expression in human subjects. The British Journal of Nutrition. 2011;106(4):572-582. doi: 10.1017/S0007114511000420.PubMedUsed to support: A bioavailability study showing selenium yeast raised plasma selenium and altered selenoprotein gene expression. Honest framing: effects on functional selenoprotein expression were limited, and Se-yeast composition varies between products, so status gains are not standardized.