As of April 2019, there were 46 evaluation models for NPI in the scientific literature (Carbonnel and Ninot, 2019). These models were constructed by researchers for researchers, often from a monodisciplinary perspective and rarely from a patient-centered approach. This led to significant heterogeneity in study protocols and the way NPI were conceived (approach, method, technique, or materials). The results were scattered, debatable, poorly transferable, and rarely reproducible. Consequently, these practices were not widely recognized outside the study context (dependent on the establishment and/or practitioner). This situation raised doubts about their effectiveness (e.g., efficacy, safety, relevance, utility, cost-effectiveness), their content (e.g., heterogeneity in doses, procedures, ingredients, techniques, contexts, target populations), their approval (e.g., ethics committees), their dissemination (e.g., conflicting reviewer opinions), their teaching (e.g., protocols, best practices), and their recognition (e.g., authorization, integration into official classifications, reimbursement). This lack of a consensual evaluation model for NPI suggested that each professional had to reinvent their program for every new patient, given the wide or contradictory recommendations from authorities, agencies, and scientific societies. It also implied that only the patient-provider relationship mattered in the health effects induced (Ninot, 2020). Moreover, it left the door open for pseudoscientific practices and, more broadly, parallel medicine, along with all the obscurantist, health-related, sectarian, political, and judicial issues that are known in France (Miviludes, 2022; CNOI, 2023; CNOM, 2023) and around the world (Ernst and Smith, 2018). This idea was also gaining traction in the United States in the field of oncology, aiming to juxtapose two medical offerings: one based on experimental science, primarily focused on surgery, medication, radiotherapy, and medical devices, and the other described as "complementary, integrative, or traditional," based on individual experience, opinions, and traditions (Mao et al., 2022). This second offering claimed exclusivity in the domains of prevention and care, emphasizing care for the person versus cure for the disease. Thus, the NPIS Model was co-constructed with the idea that experimental science could demonstrate the existence of effective, safe, and reproducible prevention and care protocols. This work was supported by seed funding for participatory research from INSERM and involved over 1,000 participants under the guidance of a committee of 22 multidisciplinary experts, including two user representatives. This transdisciplinary innovation is currently supported by 30 French scientific societies, the National Center for Palliative Care and End of Life, INCa, and the French Platform for Clinical Research Networks.

An evidence-based data point is a theoretical or practical knowledge acquired through rigorous and integrated scientific methods and reasoning. The NPIS Model follows this logic in the health field (see Figure 3). It provides specific methodological and ethical recommendations for NPI for studies focusing on their mechanisms and explanatory processes (mechanistic study), their content (prototypical study), their evolution over time (observational study), their benefits and risks (interventional study), and their application and personalization modalities (implementation study).

Each NPI file in the NPI Registry has been submitted by a practitioner or researcher through the dedicated platform hosted by the NPIS. Each file undergoes review by an independent and integrated scientific committee. This committee invites relevant scientific societies and health authorities to validate the NPI files and/or to oversee the decisions made. Each validated file is then reviewed by a committee of users and professionals. Once labeled NPIS©, the file is translated into at least English and French and integrated into the NPI Registry.

The file contains standardized content supported by scientific studies that align with the NPIS definition of NPI, the expected specifications (Table 2), and the consensual evaluation framework for NPI, known as the NPIS Model. It includes a manual for professionals, an information notice for users, a section on funding options, and an area for anonymous user feedback. This ensures the file remains dynamic and part of a virtuous cycle of continuous improvement for the NPI.

A minimum of one prototypical study, one mechanistic study, two interventional studies, and one implementation study published in a peer-reviewed journal is required for an NPI proposal to be accepted by the expert committee tasked with validating the NPI file and awarding the NPIS© label. Specifically, experts must have evidence to anonymously vote on each criterion of the NPI file proposed to the NPIS by a submitter:

• Described (≥ 1 prototypical study)
• Explainable (≥ 1 mechanistic study)
• Effective (≥ 2 interventional studies)
• Safe (≥ 2 interventional studies)
• Implementable (≥ 1 implementation study in the country)

A professional must understand all the specifics of the NPI, the criteria justifying its use, how to implement its protocol, whom to contact, useful tips, required materials, and any prerequisite training needed.

Moving, eating, drinking, sleeping, talking, reading, writing, painting, listening to music, watching a movie, dancing, laughing, walking, singing, meditating, gardening, socializing, etc., are all activities of daily life. Some of these can generate joy, pleasure, personal growth, and well-being. In a democratic country, everyone is free to interpret and experience these activities in their own way. This relates to life philosophy, lifestyle, the art of living, and personal development. In other words, a daily activity is not an intervention, even if it can occasionally and randomly contribute to the health of certain individuals. Occupational activities and treatments for health problems identified by medicine are different.

The following products are not considered NPI:

• Hygiene and beauty products (shampoo, toothpaste, brush, body cream, etc.)
• Natural products (plants, food, mushrooms, essential oils, etc.)
• Health products (medications, implantable biological materials, dietary supplements, etc.)
• Medical devices (artificial organs, prosthetics, orthotics, digital applications, monitoring systems, etc.)

The following goods and services are not considered NPI:

• Cultural products or services (video games, books, podcasts, artistic practices, museum visits, theater, writing, etc.)
• Everyday consumer products or services (haircuts, aesthetic treatments, dining out, etc.)

The following actions are not considered NPI:

• Public health promotion activities (communication campaigns, videos, posters, booklets, websites, social media posts, etc.)
• Architectural adaptations (creating access ramps, etc.)
• Environmental adaptations (reforestation of a park, creation of a sports workshop, etc.)

The following approaches are not considered NPI:

• Professional disciplines (physiotherapy, psychology, dietetics, public health, etc.)
• Educational approaches (personal development, etc.)
• Esoteric practices (spiritual practices, religious worship, divination, witchcraft, etc.)

The following organizations are not considered NPI :

• Health organizations (networks, platforms, clinics, health centers, healthcare establishments, etc.)
• Health systems (digital platforms, etc.)

The following measures are not considered NPI :

• Health policies (strategies, plans, programs, etc.)
• Regulations (decrees, laws, etc.)
• Judicial decisions (warnings, convictions, etc.)

A scientific validation model for medications has existed since the 1960s, with specific regulations recognized worldwide (e.g., FDA, EMA, ANSM). A similar procedure has recently been implemented for medical devices in Europe. However, until now, no consensual model existed for nutritional, bodily, and psychosocial health services due to confusions between approach, protocol, and technique/ingredient. A participatory, pragmatic, and multidisciplinary consensus work followed international scientific health recommendations to address this for NPI (Ninot et al., 2023).

This work took into account the specificities of NPI, health risks, the balance between internal and external validity, the justification of explanatory mechanisms, ethical considerations in health, and respect for contexts of use. The NPIS Model accelerates research through the harmonization of methodological and ethical expectations in NPI. It also enhances the identification, referencing, transferability, and implementation of NPI for the benefit of user health and safety, improving the quality of training.

Ultimately, the NPIS Model distinguishes between individualized, science-based services aimed at addressing known health issues in Western medicine and occupational practices (lifestyle, art of living, work, sociocultural activity, personal development, pursuit of happiness, spiritual practice, etc.). In this sense, the model does not impede individuals' freedom to choose a particular lifestyle. It aims to address a specific health issue for an individual or a group of people within a limited timeframe and a framework regulated by the health sector. The NPIS Model encourages innovations across all other health sectors, particularly in health organizations and early identification actions for health problems.

The NPIS has outlined a roadmap from 2021 to 2030 aligned with the strategies of European and international health institutions. To this end, it has initiated discussions with the European Public Health Association (EUPHA), involved in health service innovation, the European Centre for Disease Prevention and Control (ECDC), which is planning to create a registry, the European Commission, which aims to promote "health, nutrition, mental health, and psychosocial support to communities," and WHO Europe, which intends to identify the "most effective health interventions" by 2030. The NPIS submitted several European projects in 2024.

The NPIS is also engaging with WHO, which has advocated for "self-care interventions" since 2022, included NPI in its Global Action Plan for Mental Health published in 2022, and identified "the most effective and feasible interventions in a national context" in a report published in 2021. Additionally, it is collaborating with other international organizations such as UNESCO, which has promoted "specific health and well-being education interventions" since 2016, UNICEF, which has advocated for sharing "effective health interventions" since 2016 and developing "primary healthcare" since 2018, the UN, which has called for "accelerating essential health services" since 2023, and the Coalition of Partnerships for Universal Health Coverage and Global Health, advocating for "people-centered, comprehensive, and integrated services" since 2021.

Thus, an ecosystem for NPI, from research to practice through training and delivery, is being constructed, with NPIS actively participating. It involves all stakeholders, both academic and non-academic, to create a true value chain benefiting personalized and precision medicine based on science, sustainable health, and equitable longevity. With over 2.1 billion people aged over 60 by 2050, multistakeholder collaborations will be the foundation of a sustainable and equitable longevity economy.

This is why forums on NPI have been organized since 2024 in France and Europe, called NPIS Forum. An international summit titled NPIS Summit takes place every year in October, and regional events called NPIS Satellite gather professionals and users around a health theme.