Selenium 200mcg Selenomethionine

Description

Selenium 200mcg as L-selenomethionine, the organically bound form, in a small capsule. Two things on that label deserve a second look. The form, because selenomethionine and sodium selenite behave differently in published absorption work, and the amount, because a selenium 200mcg capsule is about three and a half times the adult recommended intake of 55 micrograms and half of the tolerable upper limit of 400.

Label figures

Why a selenium 200mcg capsule sits where it does

Because 200 mcg is the figure the large intervention trials used, not because it is a nutritional target. The intake reference is 55 mcg and a couple of brazil nuts can exceed that on their own. This is a research dose product, and the distance between 200 and the 400 mcg upper level is the reason the upper level is printed on this page at all.

Anyone already taking a multivitamin should add the two figures together before buying, since selenium appears in most of them. The NIH selenium fact sheet carries the intake table, the food sources and the toxicity discussion, and it is free.

Selenomethionine against the inorganic forms

Sodium selenite and sodium selenate are inorganic salts and are cheaper. Selenomethionine is the amino acid bound form, which is how selenium occurs in food, and published absorption studies have measured higher retention from it. Selenium yeast is a third option and varies in composition between producers. Form is named in full here, as it is for every mineral on the minerals page.

What the trials measured

The large studies administered 200 mcg of L-selenomethionine daily over several years and measured clinical incidence endpoints alongside plasma and red cell selenium concentrations. The best known of them did not find benefit on its primary endpoint and was stopped early for futility, while an earlier smaller trial had reported differences. That is a description of the published record, including the result that does not flatter the ingredient, and it is not a claim about this bottle.

Selenosis, and why the upper limit exists

Chronic intakes well above the upper level have been measured to cause hair and nail brittleness and loss, a garlic odour on the breath and gastrointestinal upset. This is one of the few micronutrients where the gap between a research dose and a toxic intake is narrow enough to be worth printing on a product page.

Selenium 200mcg against a multivitamin dose

Most multivitamins carry between 25 and 70 mcg, which covers the reference intake and nothing more. A selenium 200mcg capsule is a deliberate step above that, and the two are frequently taken together without anyone adding them up. Doing the addition before buying is the whole point of printing both numbers on the page.

Why a selenium 200mcg capsule is small

Micrograms take up almost no room, so the capsule is mostly carrier. That is normal for a trace mineral and it is why the assay matters: at these weights, a blending error is invisible to the eye and obvious on a chromatogram.

Food, for context

For selenium 200mcg comparisons, brazil nuts, tuna, sardines, eggs and organ meats are the dense food sources, and brazil nuts vary so widely by soil origin that a single nut can carry anywhere from under 50 to over 90 micrograms. Soil selenium content is the underlying variable in all of it.

Testing

Every lot of selenium 200mcg is assayed for elemental content by an independent laboratory and screened for heavy metals and microbials, which matters here because mineral material is mined and refined rather than grown. Under or over strength lots are withdrawn and the certificate stays published, as described in why we publish the batch that failed.