Monosodium Glutamate (MSG)
Hydrolyzed protein is a solution derived from the hydrolysis of a protein into its component amino acids and peptides usually done with prolonged heat and hydrochloric acid. It is a flavor enhancer that is used to create MSG in the food industry. The chemical breakdown of hydrolyzed proteins releases glutamic acid which is combined with sodium to produce MSG. It is not usually listed separately on food labels when used to produce MSG. Hydrolyzed Proteins are also used in making some infant formulas. Extensively Hydrolyzed Formulas eHF and Partially Hydrolyzed Formulas pHF refer to the degree of hydrolysis of proteins used in infant formulas designed for babies with allergies to cow's milk protein.
Infant formula made with hydrolyzed protein may be a good option for infants who use formula and are allergic to dairy. However hydrolyzed protein does contain glutamate, the same ingredient in MSG which may cause headaches, muscle tightness, numbness, tingling, weakness and flushing in some people. People who are sensitive to MSG should avoid hydrolyzed protein.
A perspective on partially hydrolyzed protein infant formula in non exclusively breastfed infantshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC6528056/
A Systematic Review of the Role of Hydrolyzed Infant Formulas in Allergy Preventionhttps://jamanetwork.com/journals/jamapediatrics/fullarticle/486115