Concentrate and isolate are the same protein at different purity levels, and the right choice is mostly a price and stomach question, not a quality question.
The actual differences
- Protein content: concentrate is typically 70 to 80 percent protein by weight; isolate is 90 percent or more.
- Lactose and fat: isolate has most of both filtered out, which is why it sits lighter if dairy bothers you.
- Price: concentrate is almost always cheaper per gram of actual protein.
How to choose
If concentrate agrees with your stomach, buy whichever is cheapest per 20 g of protein, which is usually concentrate. If you get bloating or discomfort, or you want maximum protein in minimum volume (common on a suppressed appetite), isolate earns its premium.
Ignore the label, do the math
A cheap tub with small servings can cost more per gram than an expensive tub with dense ones. The formula: cost per 20 g = (price / servings) x (20 / protein per serving). We maintain a running ranking of whey by real cost per 20 g of protein so you do not have to compute it in the supplement aisle.
Not sure how many grams you need in the first place? Get your daily target here, then buy by cost per serving.
General information, not medical advice.
For how whey compares with whole foods on price, see the cheapest high-protein foods ranked by cost per 20 g.
GramGoal Team. We build nutrition calculators and price-check the supplement market monthly. General information, not medical advice. See our methodology and affiliate disclosure.