Hydrolyzed Proteins

What "hydrolyzed" means

To hydrolyze a protein is to split it into smaller pieces using water together with enzymes, acid or fermentation. The result, a protein hydrolysate, is a mixture of free amino acids, short peptides and sometimes larger fragments. A 2024 review describes food-derived peptides as produced from dietary proteins through enzymatic hydrolysis or fermentation. [1] Hydrolysates can be made from many protein sources; a 2026 review lists animal by-product proteins such as collagen, muscle proteins, whey and egg proteins. [2]

Hydrolyzed proteins appear in three different settings that are easy to confuse: sports and general-use powders, infant and medical formulas, and food ingredients (flavorings, broths, protein bars). Each has its own evidence. A hydrolysate is not a drug, and it is not a single compound: two products called "hydrolyzed whey" can contain very different mixtures, because raw-material differences and batch variability limit how reproducible these ingredients are. [2]

For protein as a nutrient (quality, amounts, muscle, older adults), see amino acids and protein, whey protein and protein quality and complete proteins. This page covers only the hydrolysate question.

Adult trial evidence

• Blood sugar after meals. A 2024 systematic review and meta-analysis (29 randomized trials pooled) found that protein hydrolysates lowered the blood glucose rise after a meal compared with controls, by about 0.22 mmol/L in adults with normal glucose and about 0.88 mmol/L in adults with high glucose. After-meal insulin was higher. Over longer periods there was a small reduction in fasting glucose and HbA1c. [3] Label: promising but limited (biomarker). The review does not show fewer diabetes complications, and it does not show a supplement should replace diabetes care.
• Blood pressure with an egg hydrolysate. In a 2026 meta-analysis of 30 trials of egg-derived proteins and peptides, one egg protein hydrolysate showed no significant effect on blood pressure (two trials). [4] Label: no good evidence of benefit for that outcome.
• Muscle and other claims. Sports-nutrition claims for hydrolysates are covered under protein pages in the Amino Acids & Protein section rather than here, because they concern protein amount and quality as much as the hydrolysis step.

Infant formulas

Hydrolysates are best known in infant formulas, where hydrolysed proteins have been used to treat infants with allergy or food intolerance. [5] These are specialized products for specific situations. Decisions about infant feeding belong with a pediatrician.

• Treating cow's milk allergy. A systematic review of 15 randomized trials (1,285 children) found extensively hydrolyzed formulas appear well tolerated by most children with cow's milk allergy, but the trials had many methodological problems and did not allow a conclusion about which formula is better. [6]
• Trying to prevent allergy. A Cochrane review (published 2006, so older) found no evidence to support hydrolyzed formula to prevent allergy compared with exclusive breastfeeding, and only limited evidence in high-risk infants who cannot be fully breastfed. [5] A 2017 meta-analysis of one type of partially hydrolyzed whey formula found reduced eczema and allergy risk in high-risk infants but rated the certainty of evidence as low, and noted that not all hydrolyzed formulas are equal. [7]

Label: mixed, with low-certainty evidence for prevention.

Allergy, taste and quality concerns

• A review of food-derived bioactive peptides says allergenic and toxic peptides can arise while food proteins are hydrolyzed, and that unwanted chemical changes such as Maillard reactions can occur during processing. [8] [8] Hydrolyzing a milk, egg or fish protein does not by itself make it safe for someone with that allergy.
• The U.S. names milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans and sesame as the major food allergens. [9]
• The FDA has a rule on how fermented and hydrolyzed foods can carry a "gluten-free" claim. [9] A "hydrolyzed" label tells you little about what is left in the product.