Several publications indicate that the amino acid arginine has an enormous effect on hair growth. As a precursor to nitrogen oxide, it is of vital importance for hair growth. The vasodilatory effect of arginine promotes hair growth as the nitrogen oxide generated from arginine opens the potassium channels of the cells. The blood supply to the hair root is then improves, which in turn stimulates hair growth. Crucially, they form keratin, the protein that makes up the majority of your hair strand (around 88%). Amino acids also make red blood cells that carry oxygen and nutrients to the hair follicles.