Gibberellin A4 is a C19-gibberellin, initially identified in Gibberella fujikuroi and differing from gibberellin A1 by the substitution of the OH at C-7 (gibbane numbering) by H. It has a role as a plant metabolite. It is a lactone, a gibberellin monocarboxylic acid and a C19-gibberellin.