Uptake and Utilization of Amino Acids by Human Hair Follicles and Related Cells

This study investigated the role of amino acids in human hair follicles, focusing on cysteine and arginine. It found that both amino acids were essential for hair growth and protein synthesis. Cysteine influenced hair fiber diameter, with reduced supply leading to thinner fibers and slower growth. Hair follicles utilized the amino acid transporter ASC for cysteine uptake, while arginine was primarily incorporated into proteins in the hair root sheaths and fibers. Arginine also affected energy metabolism, as its availability influenced lactate production. The study noted that hair follicles did not express certain peptide transporters and suggested a slower mechanism for glutamate transport compared to other amino acids.