Whey Protein Isolate

About

What it is and where it shows up.

Whey protein isolate (WPI) is a highly purified dairy-derived protein ingredient (typically ≥90% protein by dry weight) obtained from cow's milk whey—the liquid by-product of cheese manufacturing—through ultrafiltration, ion-exchange chromatography, or microfiltration processes that remove fat, lactose, and ash. It is widely used in sports nutrition, meal replacements, infant formula, and fortified foods as a high-quality, complete protein source rich in essential and branched-chain amino acids.

Safety summary

The regulatory and scientific consensus.

WPI carries a broad regulatory safety consensus, being GRAS-affirmed by the US FDA for general food use and assessed as safe by EFSA under multiple novel food opinions, with a NOAEL of 2000 mg/kg bw/day established in subchronic rat studies and no genotoxicity concerns identified. As a cow's milk-derived allergen, it must be strictly avoided by individuals with diagnosed cow's milk allergy, and trace residual lactose may cause gastrointestinal discomfort in highly sensitive lactose-intolerant individuals. High-dose supplementation warrants medical supervision in individuals with pre-existing kidney disease due to elevated renal protein load.

Regulatory landscape

What food-safety regulators have decided.

Jurisdiction	Status	Note
EFSA (European Food Safety Authority) (European Union)	Approved	Extended uses of whey basic protein isolate in foods for special medical purposes and food supplements for infants confirmed safe; proposed extended uses found not to increase potential intake beyond levels assessed in the 2018 opinion.source
FDA (Food and Drug Administration) (United States)	Approved	Whey protein isolate affirmed as GRAS via GRN 000037 (no-objection letter). Whey and whey protein concentrate are also independently GRAS-affirmed under 21 CFR 184.1979 and 184.1979c for general food use with no limitation other than current good manufacturing practice (cGMP).source
FSSAI (Food Safety and Standards Authority of India) (India)	Under_review	Draft Food Safety and Standards (Food Products Standards and Food Additives) Amendment Regulations, 2024 introduces formal compositional and quality standards for Whey Protein Isolate alongside Whey Protein Concentrate (uploaded 07-10-2024; under public comment process). Whey protein concentrate standards were previously codified in FSSR 2011 amendments (2018). WPI is currently regulated under the broader FSS dairy products framework (Chapter 2.1).source

Who should approach with care

Whose guidance would steer them away.

Other — Individuals with documented cow's milk allergy (IgE-mediated) must avoid WPI entirely, as EFSA notes novel foods derived from allergenic sources including dairy retain allergenicity potential of the source regardless of processing.

Lactose Intolerance — Although WPI contains minimal residual lactose compared to whey protein concentrate, trace amounts may remain after filtration and could provoke gastrointestinal discomfort in highly sensitive individuals.

Kidney Disease — High-dose whey protein supplementation imposes an elevated nitrogen load on the kidneys; individuals with pre-existing chronic kidney disease should seek medical supervision before use, consistent with general clinical guidance on high-protein diets in renal impairment.

Infants — Use of WPI in infant feeding is subject to strict compositional and clinical safety requirements under EFSA Regulation (EU) 2016/127 and FSSAI Infant Nutrition Regulations 2020; unsupervised supplementation outside approved infant formula is not recommended.

Research citations

The sources behind this verdict.

1FDA. GRAS Notice No. GRN 000037: Whey Protein Isolate and Dairy Product Solids. hfpappexternal.fda.gov
2FDA. Agency Response Letter GRAS Notice No. GRN 000633 (referencing 21 CFR 184.1979 and 184.1979c). fda.gov
3FSSAI. Draft Food Safety and Standards (Food Products Standards and Food Additives) Amendment Regulations, 2024 — Standards for Whey Protein Concentrate and Whey Protein Isolate, 2024. fssai.gov.in
4EFSA. Safety of whey basic protein isolate for extended uses in foods for special medical purposes and food supplements for infants pursuant to Regulation (EU) 2015/2283, 2019. efsa.europa.eu
5EFSA. Safety of Whey basic protein isolates as a novel food pursuant to Regulation (EU) 2015/2283, 2018. efsa.europa.eu
6FSSAI. FSSAI Includes Standards for Whey Protein Concentrates and Colostrum Products in FSSR 2011, 2018.

Independently researched6 citations