Is Gold Standard whey an isolate?
No — Optimum Nutrition Gold Standard 100% Whey is a whey concentrate + isolate blend, not a pure isolate, despite the product name. The Supplement Facts panel, not the front label, discloses the actual composition; the label lists 24g protein per scoop.
This is one of the most common label misreadings in the protein aisle, and it's built into the product name. "Isolate" and "concentrate" are processing-level terms with different typical label numbers, so a blend of the two is a meaningfully different label than a pure isolate — here's how to read it.
Isolate vs concentrate: what each term means on a label
Isolate and concentrate are processing-level label terms, not health claims. Whey PROTEIN ISOLATE is filtered further, so labels typically show a higher protein percentage by weight (commonly in the 90%+ range) and lower fat/carb/lactose content per label. Whey PROTEIN CONCENTRATE is filtered less, so labels commonly show a lower protein percentage by weight (roughly 70–80% range) with more residual fat, carbs, and lactose per serving. Neither term on its own tells you the blend ratio if a product lists both.
The product in question
Optimum Nutrition 100% Whey Gold Standard
Whey concentrate + isolate blend, label lists 24g protein/scoop, Informed Choice certified (select SKUs)
One of the most widely available proteins carrying a third-party banned-substance-testing certification on at least some SKUs — check the specific tub for the certification mark before assuming it applies.
Best for: Buyers who want to cross-reference a certification mark against the label's protein-per-scoop math
Watch out: It is a concentrate/isolate BLEND, not 100% isolate, despite the product name — the Supplement Facts panel, not the front label, tells you the actual split. Certification also varies by flavor/SKU; verify the specific one you're buying in Informed Choice's own database.
See it on AmazonIf you specifically want a pure isolate label
Look for a Supplement Facts panel whose protein source line reads whey protein isolate alone. One example with a verifiable certification on top: Klean Athlete Klean Isolate, NSF Certified for Sport — covered in our third-party-tested roundup.
Frequently Asked Questions
No. Optimum Nutrition Gold Standard 100% Whey is a whey concentrate + isolate blend, not a pure isolate, despite the product name. The Supplement Facts panel — not the front label — is where the actual composition is disclosed. The label lists 24g protein per scoop.
The "100%" in the name refers to the marketing framing of the product, not to isolate content. Isolate and concentrate are processing-level label terms: isolate is filtered further (labels typically show a higher protein percentage by weight, commonly 90%+), concentrate is filtered less (commonly roughly 70–80% by weight, with more residual fat, carbs, and lactose per serving). Neither term on its own tells you the blend ratio when a product lists both.
Read the ingredient list on the Supplement Facts panel. If it lists whey protein isolate alongside whey protein concentrate (or a 'protein blend' containing both), it is a blend regardless of what the front of the tub says. A pure isolate product lists whey protein isolate as the protein source.
Select SKUs carry Informed Choice certification — a banned-substance-testing certification — but certification varies by flavor and SKU, so verify the specific tub you're buying in Informed Choice's own database rather than assuming it applies.