<p>Plant biostimulants are increasingly applied in agriculture to enhance crop performance and contribute to more sustainable production systems. Their adoption by farmers depends largely on product availability, regulatory accessibility, and demonstrated efficacy under field conditions. Under EU Regulation (EU) 2019/1009, plant biostimulants are defined as products that improve nutrient use efficiency, tolerance to abiotic stress, or crop quality traits, explicitly excluding direct plant protection claims. This paper reviews the current definition of plant biostimulants, outlines the development of the EU legal framework, and summarizes the requirements for market placement within the European Union. Particular attention is given to the coexistence of two regulatory pathways: the harmonized EU framework applicable since June 2022 and pre-existing national regulatory systems. Their respective advantages and limitations are critically assessed in relation to different market strategies. The biostimulants are known to influence plant physiology through multiple mechanisms and their effect may not always be clear when it comes to the distinction between biostimulation and plant protection. The harmonized EU procedure offers obvious advantages for manufacturers targeting multi-country markets and developing innovative products, whereas national pathways may remain more suitable for companies operating in localized markets with established distribution networks. Overall, this analysis highlights a conceptual and regulatory gap between the legally defined functions of biostimulants and their scientifically recognized multifunctionality, with implications for future policy development and product innovation.</p> Graphical abstract <p></p>