Gibberellin A53 (GA53) is a tetracyclic diterpenoid carboxylic acid belonging to the gibberellin family of plant hormones. It is characterized by the molecular formula C20H26O5 and the specific stereochemistry (1S,4R,8S,12S)-12-hydroxy-4,8-dimethyl-13-methylidenetetracyclo[10.2.1.0^{1,9}.0^{3,8}]pentadecane-2,4-dicarboxylic acid. It is a biosynthetic intermediate in the gibberellin pathway. As a native gibberellin, GA53 serves as a key precursor in the biosynthesis of other bioactive gibberellins, such as GA1 and GA4, in plants. Its primary application and research interest lie in the field of agriculture as a plant growth regulator. Gibberellins, including intermediates like GA53, are studied for their ability to promote stem elongation, seed germination, fruit development, and flowering, making them valuable in horticulture and crop production. While not a final commercial product itself, GA53 is a crucial standard and reference compound for biochemical and metabolic studies of gibberellin pathways. It is used in research to understand plant development, hormone signaling, and to develop strategies for modulating plant growth. It is also isolated and studied as a natural product.