Hair and Amino Acids: The Interactions and the Effects

The study discussed the interactions and effects of various amino acids in hair care applications. It found that amino acid uptake by hair is influenced by ionic equilibrium when applied in simple aqueous solutions, but this changes when amino acids are incorporated into hair conditioners, highlighting the role of interactions with cationic surfactants. Specifically, combining pyrrolidone carboxylic acid (PCA) with arginine enhances uptake due to arginine's strong affinity for hair. The study also noted that alanine in conditioners improves the hydrophobicity of bleach-damaged hair, while histidine and phenylalanine enhance tensile strength. Additionally, PCA was effective in improving color retention in dyed hair.