Mg, mcg and IU when reading licorice root extract
Licorice root extract mg vs mcg comes down to one conversion: a microgram is a thousandth of a milligram, so 500 mcg is 0.5 mg and not 500 mg. Get that backwards and a label that looks 1000 times stronger is actually 1000 times weaker, which is the whole reason unit errors outrank ingredient errors in shopping mistakes.
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The mg vs mcg arithmetic, done once
1 mg equals 1000 mcg. A 1000 mcg dose is 1 mg. An IU is a different animal, because it describes biological activity rather than weight, and you cannot convert it without knowing which nutrient you are holding.
That is why vitamin D, vitamin A, and vitamin E all carry IU figures that convert differently. For anything sold by weight, the mg and mcg question is simple division. For IU, look up the specific nutrient before you compare anything at all.
Converting before you compare
Put both products into the same unit first, then compare per serving. A bottle listing 500 mcg per capsule against one listing 0.8 mg per capsule is a comparison between 0.5 mg and 0.8 mg. Now the choice is obvious, and 30 seconds of arithmetic got you there.
I have done this comparison wrong twice, both times in the same direction, both times because the larger number felt like the stronger product. A bigger numeral is not a bigger dose, and the decimal point is doing all the work.
Where licorice root extract fits
Extract products vary widely in strength and in what they are standardised to, and the panel is where that shows up. Serving size first, then the figure with its unit, then the capsules per bottle, then the cost per day. Four fields and one line in a note, and no ambiguity left.
At 1 capsule per serving and 120 capsules for $18.60, that is about $0.16 a day. Written that way, two products become comparable even when the panel typefaces are wildly different, which they usually are.
A habit that catches the errors
Before comparing anything, write both figures in milligrams. If one is a decimal smaller than 1, write it as mcg instead. Seeing 0.5 mg next to 500 mcg on the same line makes the relationship impossible to misread.
It takes about 20 seconds and it has caught mistakes I would otherwise have made at the till. Unit conversion is the least interesting part of label reading, and it's the part that decides the comparison. Do the division once, write it down, and the rest of the panel gets much easier to read.
Where IU still trips people up
IU isn't a weight at all, and you can't convert it with a decimal shift. Vitamin D, vitamin A and vitamin E each convert differently, so a 400 IU figure means something different depending on which of them you're holding.
If a panel mixes IU and mcg across two products, don't compare them directly. Find the conversion for that specific nutrient first, then convert both to the same unit. I've skipped that step once and compared 2 figures that had nothing to do with each other.
Four fields, one line, every time
Milligrams in one unit. Serving size. Capsules per jar. Cost per day. I write those 4 things for every product I buy, and the conversion happens once, on the day I bring it home, rather than every time I stand in front of a shelf trying to remember.
It sounds like more work than it is. The whole note is 1 line, and 1 line has saved me from a decimal error that would have cost 1000 times the difference it looked like.
Write both numbers in the same unit, keep the line, and move on.
Frequently asked questions
What is the difference between mg and mcg?Show answerHide answer
A microgram is a thousandth of a milligram, so the number looks much larger.
Why do some labels use IU?Show answerHide answer
Older units like IU describe biological activity rather than weight.
How do I compare across units?Show answerHide answer
Convert to the same unit first, then compare per serving.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
