HealthWise® L-Arginine HCL is 100% pure pharmaceutical grade amino acid. L-Arginine has numerous functions in the body and is considered a semi-essential amino acid as the body cannot always manufacture enough for daily requirements. HealthWise® L-Arginine uses pure arginine hydrochloride as it is freely soluble in water and well absorbed. Did you know? An important clinical test uses arginine to trigger the secretion of HGH from the pituitary. This is used to identify levels of GH deficiency.