The dominant narrative around dementia argues that progression cannot be halted or reversed. However, evidence on multimodal non-pharmacological treatments formulated around a ‘personalised medicine’ approach challenges this view. This paper reviews the current evidence for dementia prevention utilising such treatments and explains the logic of applying personalised medicine. The functional medicine treatment approach to ‘root cause’ analysis is presented as currently practiced with patients experiencing cognitive decline. We report six case reports including in-depth practitioner evaluations, recommendations and follow-ups. We cover the various presentations of memory and concentration problems and the screening process with advanced functional testing. The case reports appear in a table, followed by 11 key points, insights and findings. To our knowledge, this is the first paper reporting practitioner case reports documenting improvements in symptoms of memory decline in patients from the UK, Greece and New Zealand. Four patients had initial presentations and follow-up improvements verified by standardised screening instruments and/or formal diagnosis. Two patients had symptom improvements verified through selfreport and proxy-report. Practitioners reported improvements through biomarkers (normalisation of serum levels, folate and homocysteine, thyroid function, blood sugar levels), as well as weight loss, decreased blood pressure and reduction in medications. They also reported improved mental, physical, social, energetic, emotional and spiritual functioning. The next phase is an enhanced intervention alongside the existing UK National Health Service memory assessment pathway. This paper advocates for personalised medicine in the UK for persons living with memory problems and dementia, driven by this increasing evidence base.