Selenium
Of 7,788 on-market selenium products in the January 2026 DSLD dump, the median declared dose is 55 elemental mcg, and 36.6% list unspecified/undisclosed form as the primary form.
Form share
Of 7,404 products with an identifiable primary form, here is the share held by each form of Selenium on the market today.
Embed this chart
Free to embed on your site or article — attribution and a link back are built into the frame.
| Form | Quality tier | n | Share |
|---|---|---|---|
| unspecified/undisclosed form | Unrated | 2,711 | 36.6% |
| L-Selenomethionine | Tier 1 | 2,697 | 36.4% |
| Selenium Amino Acid Chelate | Unrated | 811 | 11.0% |
| Sodium Selenate | Tier 2 | 657 | 8.9% |
| Sodium Selenite | Tier 2 | 528 | 7.1% |
Form share over time
Entry-year breakdown of the top forms, 2012–2025.
Dose distribution
Deciles of declared dose per serving (elemental mcg), among 7,612 products with a disclosed amount, against the RDA of 55 and UL of 400.
Embed this chart
Free to embed on your site or article — attribution and a link back are built into the frame.
- 32.2% of products fall below the fairy-dust threshold (40 mcg, 20% of the studied low dose).
- 1.2% of products don't disclose an amount because Selenium is declared inside a proprietary blend.
Where does your dose rank?
Enter a per-serving dose (elemental mcg) to see exactly how it compares to the 7,612 on-market selenium products with a disclosed amount. The chart above groups doses into deciles; this looks up the exact percentile for one number.
By dosage form
By target group
Top brands
Search interest over time
How often people search for selenium on Google, US only, the last 5 years. This is public interest, not DSLD label data — a spike here doesn't necessarily line up with anything on this page, and Google's own index (100 = that term's peak popularity in the chosen window) is relative, not an absolute search-volume count.
Or see this search directly on trends.google.com.
Forms explained
Label discloses only "Selenium" with no compound specified.
Elemental fraction: 40.3% (C5H11NO2Se, single defined molecule, no hydration ambiguity)
Retained longer than inorganic selenite/selenate (organic forms show higher retention; Fairweather-Tait 2010); the form used in SELECT. The NPC trial is reported to have used selenium-enriched yeast (not confirmed from the abstract).
Source: Fairweather-Tait SJ et al. 2010, Am J Clin Nutr 91(5):1484S-1491S, PMID 20200264; Lippman SM et al. 2009, JAMA 301(1):39-51, PMID 19066370; Clark LC et al. 1996, JAMA 276(24):1957-1963, PMID 8971064
Terminology inconsistent across manufacturers; composition cannot be determined from the name alone.
Source: none (definitional caveat; no source defines the composition of "selenium amino acid chelate")
Elemental fraction: 21.4% (Na2SeO4 x 10H2O, decahydrate (described as the common supplement ingredient form vs 0.418 anhydrous -- spot-check against labels))
Inorganic selenate is well absorbed but, like selenite, less well retained in tissue than organic selenomethionine, per a general bioavailability review (organic forms show higher retention than inorganic forms); no selenate-specific human study is cited.
Source: Fairweather-Tait SJ et al. 2010, Am J Clin Nutr 91(5):1484S-1491S, PMID 20200264
Elemental fraction: 45.7% (Na2SeO3, anhydrous (standard dietary-supplement/premix form; a pentahydrate at 0.300 also exists -- check specific labels))
Well absorbed but less well retained than organic selenomethionine (organic forms show higher retention than inorganic forms; Fairweather-Tait 2010).
Source: Fairweather-Tait SJ, Collings R, Hurst R. 2010, Am J Clin Nutr 91(5):1484S-1491S, PMID 20200264
Reference values
- RDA (adult): 55 elemental mcg
- Tolerable Upper Intake Level (adult): 400 elemental mcg — Basis: hair and nail brittleness/loss (IOM 2000, per NIH ODS). EFSA (2023) set a lower UL of 255 mcg/day for adults.
- Studied clinical dose range: 200–200 mcg
- Lippman SM et al. 2009 (SELECT trial), JAMA 301(1):39-51, PMID 19066370 -- 200mcg/day L-selenomethionine did not reduce prostate cancer incidence in 35,533 men (median follow-up 5.5yr of a planned 7-12; selenium HR 1.04, 99% CI 0.87-1.24); the vitamin E arm showed a nonsignificant increase (later follow-up significant: Klein EA et al. 2011, PMID 21990298). Corroborated by Clark LC et al. 1996 (NPC trial), JAMA 276(24):1957-1963, PMID 8971064 (n=1,312, 200mcg/day, mean 4.5yr). Both cited trials used 200mcg/day, so low and high are both 200; no cited trial supports a lower studied dose.
- Note: unit_basis is elemental mcg, not mg, unlike most other minerals in this list.