Talk:International unit

Confused
I am confused, so if I had capsul of 20 I.U and I took two would that equal 40 I.U? If I have a topical vitamin E of 12,000 I.U is it 12,000 I.U total, bottle size or is it 12,000 I.U per application? Do two 12,000 I.U bottles equal 24,000 I.U or is it still 12,000 I.U?


 * If you take two 20 I.U. capsules then you get a total of 40 I.U., yes. Twice the amount means twice the I.U.'s. Whether the 12,000 I.U. number is per bottle or per application depends on what exactly is written on the bottle. AxelBoldt (talk) 18:40, 16 March 2008 (UTC)

Seeming contradiction
In the introduction, it says, "In order to remove the possibility of having the letter: "I" confused with the digit: "1", some hospitals have it as a stated policy to omit the "I", that is: 'to only use U or E when talking and writing about dosages'..."

Whereas, in section "Difference from unit of enzyme activity" it clearly states that one should not drop the I since "The IU should not be confused with the enzyme unit, also known as the International unit of enzyme activity and abbreviated as U."

How can these both be true?! — Preceding unsigned comment added by Shinyparticle (talk • contribs) 15:49, 20 June 2011 (UTC)

It seems that the international units were designed to cause confusion around the subject. Way to go, pharmaceutical lobbyists! — Preceding unsigned comment added by 94.22.69.164 (talk) 19:30, 7 January 2012 (UTC)

Well, to give the benefit of the doubt to the vitamin and related industry, and the hospital mentioned in the first comment, my guess is that the hospital intended to use U (without the I) for International Unit, and E (again without an I) for Enzyme unit. I know, I'm guessing -- don't bet anything on my guess. It would be nice if someone with knowledge of actual typical hospital practices would chime in, but of course, those practices might differ by country, hospital, or phase of the moon.Rhkramer (talk) 16:22, 22 December 2019 (UTC)

Can I also add this apparent contradiction? In the first paragraph it states "for the purpose of easier comparison across substances". Then in the second paragraph it says "Since the number of IUs contained in a new substance is arbitrarily set, there is no equivalence between IU measurements of different biological agents". So is it for comparing across substances or not?

unit of IU of Insulin
The atricle writes: ‹1 IU is equivalent to 0.0347 mg of human insulin (28.8 IU/mg).› It is confused. mg is a unit of mass. IU/mg is a unit of the mass fraction (a concentration-like unit). Which is correct? ZJ (talk) 12:25, 31 October 2012 (UTC)

1 µIU of Insulin = 6.945 pmol or 5.974 pmol?
The insulin unit conversion is not consistent with his molar weight 5808 Da (g/mol): Using the insulin unit definition as 0.0347 mg/IU and human insulin molar mass 5808 g/mol: 1 IU = (0.0347*10^-3 g) / (5808 g/mol) = 5.974 * 10^-9 mol. But in other sources is written, that 1 IU of insulin is 6.945 * 10^-9 mol. Where is the mistake?

I'm running into the same problem. Did you ever solve this? El Snubbe 15:51, 7 May 2018 (UTC) — Preceding unsigned comment added by El Snubbe (talk • contribs)

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IU seems not defined for vitamin-C
according to e.g. https://lpi.oregonstate.edu/mic/vitamins/vitamin-C#RDA and https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/#h2 and https://dietarysupplementdatabase.usda.nih.gov/ingredient_calculator/calc_adult2_new.php and https://dietarysupplementdatabase.usda.nih.gov/Conversions.php and http://goldenlifehealth.com/vitamins-conversion-chart/ IU is only used/defined for some vitamins but not for vitamin C, though https://www.thecalculatorsite.com/articles/units/convert-ui-to-mcg.php says what's in the text now, perhaps from the cited book 'Ultimate Pharmacy Calculations Guide' (page not available in free preview to dbl-check). Also here https://www.etoolsage.com/converter/IU_Converter.asp and here https://mypharmatools.com/othertools/iu the calculators yield 50ug = 1IU but there's no refs. Seems the text in the article should better be changed to read the Adequate Intake (AI) or Recommended Dietary Allowance (RDA) from any refs above then, or add the these refs for the IU conversion. — Preceding unsigned comment added by 93.32.68.209 (talk) 20:32, 26 October 2020 (UTC)


 * I found a 1935 ref where it is defined. Guess that's solved. That said, I still don't see a point in mentioning it. Artoria2e5 🌉 14:25, 29 December 2023 (UTC)