Introduction
5-Aminolevulinic Acid Hydrochloride (5-ALA HCl) is the hydrochloride salt form of 5-aminolevulinic acid, a naturally occurring non-proteinogenic amino acid and a key precursor in the biosynthesis of heme, chlorophyll, and other tetrapyrroles. In medical and agricultural applications, 5-ALA HCl is used in photodynamic therapy, fluorescence-guided surgery, and as a plant growth regulator. It is converted in cells to protoporphyrin IX, which exhibits photosensitizing properties for therapeutic and diagnostic purposes. Due to its well-defined chemical structure, water solubility, and metabolic significance, 5-aminolevulinic acid hydrochloride serves as an important reference compound in biochemistry, photodynamic research, and plant physiology studies.