For a protein to be called whey isolate, it must be 90% protein per serving.
I’m having a hard time finding options.
be nice if we could put together a list.
is your isolate legit? (Grams of protein divided by serving size to get percentage of protein per serving)
Tons of whey isolate out there. Let's assume we are discussing wpi90 which is pretty much the best of the best with isolate.
But then you need to also consider the filtration. Cold microfiltration and ultrafiltration is the way to go.
Ion Exchange is extremely inferior and just pure crap so you're not getting what you think you are (I'm getting ahead of myself so I'll save that conversation for another day).
You can't use scoop weight to figure out what % whey it is. As Steve mentioned above.
You start with wpi90 and you add 2-4 grams of flavoring and sweetener and/or fiber and that lowers the % BUT you still have 90% wpi.
Let's use Ketogenics whey protein isolate as an example:
With wpi90, around 28gm of powder is needed to yield 25gm wpi, plus 3gms flavoring and sweetener, etc and now you are at 31gms "powder" in a scoop. But your method of using protein grams and total powder weight you get around 80% protein by weight. BUT it's still 90% wpi, it's not an 80% protein but protein accounts for 80% of what is in the scoop/1 serving.
For Unflavored whey you will have approx 28gm of powder in a scoop that yields 25gm wpi.
If a brand lists whey protein isolate then it's 90% protein give or take a fraction of a %. (Unfortunately many brands lie and it's not wpi90 but again I'm getting ahead of myself)...What matters after that is the filtration used and cold filtration is the way to go.
What you do need to concern yourself is when you buy a product that has whey protein concentrate (WPC) because that can be anywhere from 40% to 80% protein and lots of brands use crappy 60% WPC plus loads of flavoring and other ingredients so to the lay person it's near impossible to figure out the protein % by using the total grams per scoop. Most people assume all WPC is wpi80%, its not.
So yes, plenty of wpi90 put there.
Just avoid ion exchange (even though most brands no longer list that it's ion exchange on the label because they know people do not want that crap)... there are some small tell tale signs on a label if it's ion exchange or not and high sodium is the first red flag that it's ion exchange. (200mg)