Scott has a good point.I have my protein assayed by 2 independent, but very reputable laboratories,Miller Labs,and MVTL Labs.
Most "so-called" Whey Protein Isolates fall flat on there ass when they get tested.I have had raw material suppliers tell me they have a 97-98% Whey Protein Isolate, but when they get assayes most come up anywhere from 89-93%.The highest percentage of protein I have ever seen come up in an assay from a 97% Whey Protein Isolate have was 93.2%.
The problem is I have assayed alot of Whey Protein Isolates from suppliers that would come up as low as 78%.On average most Whey Protein Isolates when properly tested usually assay at around 87-91%.
We do private labeling and contract manufacturing for 14 diffrent companies right now.This one company we do alot of protein for sent us a bottles of Pro Lab Whey Protein Isolate 2lbs container.They wanted us to make them a product that tasted, and was similar to the Pro Lab Whey Protein Isolate.We had it assayed and it came up at 74% protein, which is pretty fat off from 89-90% .Needless to say the company changed there mind when reality hit them.
I have found that there are some Whey Protein brokers, who are not always honest.I have seen assays of so-called Whey Protein Isolates be as low as 71%, yet they claimed it was 90%.
I randomly assay all my protein that comes in to make sure I am getting what I pay for.So far I have only had like 3 batches that were slightly off, and they replaced them.I purchase around 15,0000-40,0000 lbs of protein per month, depending on what we have going on in manufacturing.So I know what I am talking about when it comes to protein.
I will be honest with you most Whey Protein Isolates when tested usually come in at around 85-91% protein, depending on the vendor, and the price you pay.Even if you buy 5000 lbs of Whey protein Isolate the stuff is not cheap.
Thats why Iso-Pure, VP2, Bio-Plex ,and True Protein charge alot for there Whey Protein Isolates, because they are paying alot.If Isolize is really 93% protein it would cost twice as much to make that protein then it would cost to make Nitro-Tech.
The reason for this is Nitro-Tech is only 70% protein,and Whey Protein Isolate costs about 2 times as much as inexpensive Whey Concentrates.
The bottom line is this, stick with reputable companies, that have a good track record.If it sounds to good to be true it usually is