Purpose Kratom (Mitragyna speciosa) is a tropical plant native to Southeast Asia, widely used for traditional and emerging therapeutic purposes. This review investigates the environmental and physiological determinants of phytochemical variation in Mitragyna speciosa (kratom), with a focus on optimizing alkaloid yield and raw material quality. As kratom gains commercial traction, particularly in Western markets, the need for standardizing cultivation practices becomes increasingly urgent. Findings Geographic origin significantly influences mitragynine content, with native Southeast Asian samples displaying higher and more consistent levels than those cultivated elsewhere. Environmental factors such as light exposure, temperature, soil acidity, and nutrient composition play crucial roles in modulating both plant morphology and secondary metabolite biosynthesis. Internally, leaf maturity, organ specificity, and vein color are linked to variable alkaloid profiles, reflecting genetic and developmental influences. Alkaloid biosynthesis is regulated not only by climate and geography but also at the molecular level through gene–environment interactions.  Studies across continents and related species further underscore the diversity and adaptability of the genus. These findings suggest that integrated, site-specific agronomic strategies are essential to support kratom’s evolution as a standardized phytopharmaceutical. Limitations Most existing studies are regionally constrained, lack standardized methodology, and rarely incorporate multi-site or molecular validation, limiting their broader applicability. Directions for future research: Future work should …