The PRODARE (PRObiotic human study Design And REporting) recommendations provide a structured framework to improve the design, conduct, and reporting of human studies involving probiotics. Developed by a multi-disciplinary expert group coordinated by ILSI Europe, PRODARE addresses key methodological challenges that have long limited the reproducibility, comparability, and interpretability of probiotic research.
Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. They are widely studied for their potential role in supporting human health. However, inconsistencies in study design, strain characterization, and reporting practices have led to heterogeneous and sometimes contradictory findings across studies. The recently published PRODARE framework supports a more consistent and transparent approach to probiotic research by complementing existing guidelines. Rather than redefining established clinical research methodologies, PRODARE complements existing study-design and reporting standards by integrating probiotic-specific considerations. These include strain-level identification, viability, stability, dosing, and product characterization — factors that are critical for the interpretation and reproducibility of probiotic studies.
The expert recommendations in PRODARE cover five major study types: exploratory studies, pilot studies, randomized controlled trials, real-world studies, and observational studies, and provide tailored guidance for each. In addition, a decision tree helps researchers select the most appropriate study design based on their research objectives.
Importantly, PRODARE emphasizes a fit-for-purpose approach, recognizing that different study designs contribute complementary evidence, from hypothesis generation to real-world effectiveness. The framework also highlights general and probiotic-specific challenges, including small effect sizes, inter-individual variability, and the need for improved biomarkers development.
By promoting standardized approaches while maintaining flexibility, PRODARE aims to strengthen the scientific basis for probiotic research and facilitate evidence synthesis, regulatory evaluation, and translation into clinical and public health applications.
Authors’ comments
Prof. Hania Szajewska (Department of Paediatrics, The Medical University of Warsaw, Warsaw, Poland), first author of the manuscript and chair of the Expert Group: “Progress in probiotics research will not come simply from conducting more studies, but from conducting better studies that address meaningful scientific and clinical questions. PRODARE was developed to support more rigorous, transparent, and standardised research practices.”
Dr. Nikoletta Vidra (previously affiliated to Science Department, Yakult Europe, Almere, The Netherlands), co-author and Expert Group member: “PRODARE contributes to the standardisation of the design and reporting of human studies involving probiotics, which is extremely relevant to advance the knowledge in that field.”
Dr. Arthur C. Ouwehand (Health R&D, IFF Health, Kantvik, Finland), co-author, co-chair of the Expert Group and chair of the ILSI Europe Probiotics Task Force: “PRODARE provides a much-needed framework for everyone conducting clinical studies with probiotics or interpreting their outcomes. Rather than imposing rigid rules, it offers guidance and flexibility to perform high-quality, fit-for-purpose research.”
Associated resources
Along with the publication, a set of resources are available on the ILSI Europe website for researchers conducting human studies involving probiotics: · A decision tree to select the study design type · A poster of the PRODARE recommendations
Citation
Szajewska H, Benninga M, Chatonidi G, et al. Probiotic human study design and reporting (PRODARE): recommendations to improve research practice. Advances in Nutrition. 2026. doi.org/10.1016/j.advnut.2026.100668
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