About Sacher AI

Specialists in behavioural AI for health, safety, and real-world impact

Sacher AI is a behavioural AI consulting and product partner for GLP-1 and digital health. We help providers design, evaluate, and deliver AI systems that drive behaviour change, support clinical and wellbeing outcomes, and meet safety and quality standards.

Who we work best with

Teams building serious health products where behaviour and trust matter.

Sacher AI is usually the best fit for teams working in higher-trust environments where user behaviour, clinical judgement, safety, and product performance all need to work together.

  • Digital health teams building patient-facing or operational AI agents
  • GLP-1, obesity, and behaviour-change programmes that need stronger engagement and retention
  • Founders and product leaders who need clearer AI strategy and safer delivery
  • Teams needing research, evaluation, or stronger external credibility for what they are building

Commercially grounded

We care about real adoption, retention, support pressure, product fit, and whether the work meaningfully changes outcomes.

Scientifically rigorous

Clinical, behavioural, and research thinking are built into the work from the start rather than added as a late review layer.

Hands-on where it matters

Some teams need strategic clarity. Others need real design, testing, delivery support, or evidence generation. We work across that full range.

Core team

Meet the people behind the work

Paul Sacher, PhD

Paul Sacher, PhD

Founder, Behavioural AI Scientist & Obesity Specialist

Founder and CEO of Sacher AI, co-founder and Research Director of the Behavioral AI Institute, and co-founder of MEND. A behavioural AI scientist and digital health clinician with 26 years across healthcare, academia, and industry.

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Emmie Fulton, DPsych

Emmie Fulton, DPsych

Health Psychologist, Behavioural Scientist & CBT Therapist

Former Global Head of Psychology at Allurion, spanning AI coach design, evaluation and safety, digital weight-loss intervention work, and the cognitive-behavioural phenotype scale. Former Assistant Professor at Coventry University, NHS clinical health psychologist, contributor to behaviour change work for Public Health England, and co-developer of the MyBarriers questionnaire.

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Gabriele Medeot

Gabriele Medeot

Machine Learning Researcher & AI System Architect

Applied AI architect with an MSc in Artificial Intelligence, focused on robust systems and practical model implementation.

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Enrico Varano, PhD

Enrico Varano, PhD

AI/ML Engineer & Predictive Modelling Researcher

AI and predictive modelling specialist for health products, with an Imperial PhD in AI and neuroengineering and published multimodal-AI research. Former Head of Data Science at a digital health startup, with postdoctoral research across Zurich and Geneva and earlier engineering experience at Airbus.

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Matthew Satterthwaite

Matthew Satterthwaite

Transformation Lead

Behavioural insight, adoption, and transformation lead with experience across large pharma, a background in neuroscience and behavioural science, and prior consulting experience.

Lev Perlman

Lev Perlman

Fractional CTO and Senior Technical Advisor

B2B and SaaS founder, mentor at Google for Startups, and architecture advisor helping teams scale execution without adding excess complexity.

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Our story and purpose

A team building the behavioural layer that makes AI work in practice

The Sacher AI story

After 26 years working across healthcare, academia, and global corporate settings, Dr Paul Sacher founded Sacher AI to do two things: help organisations build safe, effective AI systems and advance practical clinical and behavioural safety metrics for AI.

Independent by design

We do not own a front-end platform, patient app, or implementation product. That means our recommendations can be based on what gives a programme the highest likelihood of adoption, workflow fit, and long-term value.

Multidisciplinary by design

We bring together behavioural scientists, clinicians, technologists, and strategists. Everything is driven by real user needs and designed to be safe, responsible, and scalable from day one.

Leadership in behavioural AI and digital health

Dr Paul Sacher

Founder & CEO, Sacher AI · Senior Lecturer (hon), Imperial College London · Co-founder and Research Director, Behavioral AI Institute

I have spent my career on one problem: how to design programmes and products that help people change and sustain the behaviours that matter.

That work started in the clinic and in research. I co-founded MEND, a family-based obesity programme that grew to support more than 130,000 families worldwide, proven efficacious through multiple randomised controlled trials.

From there I moved into large-scale digital and AI leadership. I led the digital transformation and international expansion of Slimming World, one of the world's largest weight-management services, whose digital programme grew past a million members. At Allurion, as Global VP of Behavioural Science, I led the behavioural science team behind one of the first large-scale generative AI conversational health coaches in obesity care, and helped build the full provider and patient platform behind it. I have since advised companies in the UK and US on scaling behaviourally informed, AI-driven care.

Alongside the applied work, I publish peer-reviewed research on AI evaluation in high-stakes settings. I recently led a Wellcome Open Research open letter on behavioural science in AI, co-authored with colleagues at UCL, Harvard, Duke, Imperial, and the Alan Turing Institute, and I am a co-author of the FAST framework in Frontiers in Digital Health, a peer-reviewed framework for evaluating conversational AI health coaches.

At Sacher AI, we design and deploy behavioural AI systems for patients, clinicians, and care teams in real-world digital health, across obesity, metabolic health, and mental health.

Much of our current work is in GLP-1 care. The medications are effective for many patients, but the challenge is everything around them: keeping patients engaged, managing expectations and side effects, and supporting the behaviour change that determines long-term outcomes. More than half of patients discontinue within 12 months, even in well-resourced clinical settings. That is not a medication problem. It is a behavioural one.

What makes our approach different is that it is grounded in how people actually think and behave. We use cognitive and behavioural frameworks, including behavioural phenotyping, to understand why individual patients are likely to struggle, and design support that responds to those differences: the same pathway, delivered differently to different people. I am a named inventor on a pending US patent for digital phenotyping and personalised behavioural interventions in obesity.

Evaluation and monitoring are core to the work. We build AI systems, and we help teams see how they are performing and where the risks lie. PromptSafe is our tool for pre-deployment AI evaluation, and we are developing OVRSI for real-time monitoring of patient-facing AI.

Paul Sacher, PhD

Track record

Dr Sacher's accomplishments

  • As Global VP of Behavioural Science at Allurion, led the behavioural science team behind one of the first large-scale generative AI conversational health coaches in obesity care, and helped build the full provider and patient platform, deployed across 80 clinics in 22 countries.
  • As Chief Digital Research and Development Officer at Slimming World, led the digital transformation and international expansion of one of the world's largest weight-management services across the UK, Ireland, and the USA; its digital programme surpassed 1 million members.
  • Co-founded and scaled MEND, the largest international family-based weight-management provider, delivered across 7 countries to more than 130,000 families, and recognised by the CDC and the American Academy of Pediatrics.
  • As fractional SVP of Clinical Expansion at Lumen, supported the strategy to scale its healthcare-provider reach in the United States.
  • Directed the development of a health-span and longevity precision-medicine venture, from inception through pilot, as CEO.

Start a conversation

If you are building health AI that needs to work in the real world, we should talk.

We can quickly work out whether the right next step is strategy, delivery support, evaluation, or research.