What a label is hiding when it says blend

A proprietary blend is a legal way to print a list of ingredients without printing how much of each one is in the jar. The total is given, the order is given, and the amounts are not.

The stated reason is that the formula is a trade secret worth protecting. The practical effect is different. Ingredients on a label are listed by weight, so the first name is the one there is most of. If a blend totals 1,200 mg and lists eight ingredients, one of them can be 1,150 mg and the rest can be there in amounts a lab would round to nothing — and the label will be entirely accurate.

This is worth knowing because the expensive ingredients are usually the ones near the end of the list. A pinch of something costly is enough to put its name on the front of the jar, and the front of the jar is what sells it.

There are three things worth checking, and none of them require knowing anything about the ingredients themselves.

First, whether each name has a number next to it. If it does not, nothing else on the label can be evaluated, and the rest of this is moot.

Second, whether the numbers add up to the serving size. They rarely do exactly — capsules, flow agents and the shell account for some of it — but a serving of 1,500 mg whose named ingredients total 400 mg is mostly something the label does not mention.

Third, what form each ingredient is in. Magnesium oxide and magnesium bisglycinate are both magnesium on a label and are not the same thing to swallow; the first is cheap and the second is chelated for a reason. The form is usually printed in smaller type immediately after the name, and it is the single most informative thing on the panel.

None of this tells you whether a formula is any good. It tells you whether the label is willing to be checked, which is a different question and an easier one.