Key Facts: Protein & Supplement Labels
This page is Label Lab's maintained fact reference — the label and certification facts our guides are built on, restated in plain prose. We report what labels and certification programs state, never health-outcome claims.
Amino spiking
Amino spiking (nitrogen or protein spiking) is adding cheap free-form amino acids — most often glycine, taurine, or creatine — into a protein blend. Standard lab protein tests measure total nitrogen and back- calculate a protein number from it, so these additions inflate that number without contributing complete protein. The label tell: glycine, taurine, or creatine listed inside a "protein blend" parentheses rather than as a separately dosed ingredient. Full explainer: What Is Amino Spiking?
Isolate vs concentrate
Whey protein isolate is filtered further, so labels commonly show a higher protein percentage by weight (often 90%+) with lower fat/carb/lactose per serving. Whey protein concentrate is filtered less, commonly showing roughly 70–80% protein by weight with more residual fat, carbs, and lactose. Both terms describe processing level, not a health claim. Details: Isolate vs Concentrate Label Differences.
Proprietary blends
A "proprietary blend" line lists a combined total weight for a group of ingredients without breaking out each one's individual amount. The FDA permits this format provided ingredients are listed in descending order by weight — so you see what's in the blend and its rank order, not how much of each specific ingredient. More: Do Proprietary Blends Hide Anything?
Certification programs: Sport vs Informed vs USP vs GMP
NSF Certified for Sport and Informed Sport are both third-party programs that test finished-product lots for banned substances (referencing WADA's prohibited list) and verify label-claim accuracy. USP Verified checks that a supplement contains its labeled ingredients/amounts, screens contaminant limits, and confirms proper breakdown, historically applied more broadly across supplements. "GMP" alone describes a facility's manufacturing practices, not a finished-product test of a specific lot — a materially weaker claim than any of the three certifications above. Full decoder: What Does NSF Certified for Sport Actually Certify? and the checklist at Certification-First Buying Checklist.
Protein-per-dollar math
Divide a container's price-band midpoint by its total grams of protein (protein grams per serving × servings per container) to get a cost-per-gram-of-protein figure comparable across brands and tub sizes — a materially more useful number than price-per-pound. Methodology: How to Calculate Protein Per Dollar.
Serving-size games
A "scoop" is not a standardized unit — each brand sets its own gram-per-scoop definition. Two products with identical protein-per-scoop marketing can have different scoop weights, so the real comparison is protein grams relative to the stated serving weight in grams on the Supplement Facts panel, not the scoop count. See How to Read a Protein Label.
"Grass fed" labeling
"Grass fed" has no single mandatory federal definition governing supplement labels today — USDA's voluntary grass-fed marketing claim standard for meat was withdrawn in 2016, leaving the term largely self-defined by brands, subject to general truth-in-advertising rules. A genuine third-party certification (e.g., American Grassfed Association) is a materially different, stronger claim than an unverified phrase. Full breakdown: What Does "Grass Fed" Mean on a Label?
Protein bar label math
Sugar alcohols (erythritol, maltitol, etc.) are listed on their own Nutrition Facts line, separate from "Total Sugars." "Net carbs" is not a defined Nutrition Facts line item — it's a brand's own front-of-package calculation subtracting fiber (and sometimes sugar alcohols) from total carbohydrate, which the mandated panel itself lists as separate required lines. Details: Protein Bar Label Tricks and Protein Bar Value Math.
Creatine label terms
Creatine monohydrate is the most common single-ingredient labeled form. "Creapure" denotes creatine monohydrate manufactured by Germany's AlzChem under that company's own purity-testing program — a sourcing/ purity label distinction, not a different compound. "Creatine blends" or "formulas" combine monohydrate with other compounds inside a blend line, reintroducing proprietary-blend opacity. Full page: Creatine Label Facts.
How these facts are maintained
These facts are drawn from FDA dietary supplement labeling regulations (21 CFR 101 and 21 CFR 111), and the certifying bodies' own published program standards and public databases (NSF, Informed Sport/LGC, USP), reviewed against our guides and updated on the date shown above when a program or regulation changes. We report label and certification facts only — never health-outcome, dosage, or treatment claims. Our full methodology is at How We Evaluate.