A breakthrough diabetes jab already prescribed to thousands of NHS patients could slash the risk of developing Alzheimer's, promising research suggests. 

Liraglutide — sold under the brand name Saxenda — is offered to people with type 2 diabetes as it cuts blood sugar and aids weight loss.

Now, according to leading British experts, the once-a-day injections could also slow cognitive decline in Alzheimer's patients by as much as 18 per cent.

The researchers today said the findings 'provide hope' and could pave the way for new dementia treatments, meaning further research was vital. 

Dr Maria Carrillo, chief science officer and medical affairs lead at the Alzheimer's Association said: 'We are in an era of unprecedented promise, with new treatments in various stages of development that slow or may possibly prevent cognitive decline due to Alzheimer's disease. 

'This research provides hope that more options for changing the course of the disease are on the horizon. 

'Repurposing drugs already approved for other conditions has the advantage of providing data and experience from previous research and practical use — so we already know a lot about real-world effectiveness in other diseases and side effects.'

In the study, researchers from Imperial College London, tracked 204 patients with mild Alzheimer's at 24 clinics in the UK.  

Each took a daily injection for one year, with half receiving up to 1.8 mg of liraglutide — a standard dose given to diabetes patients — and the others a placebo.

Before the study began, all patients also underwent an detailed memory testing, PET scans and an MRI scan to evaluate brain structure and volume. These were repeated after a year. 

Over a follow-up of 12 months, researchers found patients who received liraglutide had an 18 per cent slower decline in cognitive function compared to those who got the placebo. 

Those on liraglutide also had nearly 50 per cent less volume loss in several areas of the brain, including frontal, temporal and total gray matter. 

These areas are responsible for a variety of critical functions that often are affected by Alzheimer's disease, including memory, language and decision-making.

Dr Sheona Scales, director of research at Alzheimer's Research UK, said: 'People with dementia desperately need treatments targeting the different aspects of the condition if we are to continue progress towards a cure.

'But developing drugs for diseases like Alzheimer's is costly, and can take many years. 

'This new research shows that people with early-stage Alzheimer's taking liraglutide had a slower decline in memory and thinking, and less brain shrinkage, over 12 months, compared to placebo. 

'However — the study was carried out in a small group of people. 

'Larger trials are now happening to see whether drugs like liraglutide are effective at slowing down the progression of Alzheimer's disease. 

'What remains unknown is the 'how', and more research into the mechanism behind liraglutide and its protective effect against dementia is needed.'

The scientists presented their data at the Alzheimer's Association International Conference (AAIC), in Philadelphia.  

Saxenda is already available on the health service as a weight loss treatment. 

But is only generally prescribed after a GP refers refers you to a specialist weight loss management service.

It works in a similar way to semaglutide — the active ingredient in Ozempic and Wegovy — by altering the body's metabolism, making people feel fuller and less hungry.

This leads them to eat less and, in theory, lose weight.

Saxenda, however, is one of a number of similar drugs that are experiencing a global supply shortage.

Side effects include aches and pains, diarrhoea, fever, frequent urination, and trouble sleeping.

Manufactured by Novo Nordisk, trials have found users lose an average of 6.4 per cent of their body weight over 68 weeks. 

Around 944,000 in the UK are thought to be living with dementia, with the figure is thought to be around 7million in the US.

Alzheimer's affects around six in 10 people with dementia.

It is thought to be caused by a build-up of amyloid and tau in the brain, which clump together and from plaques and tangles that make it harder for the brain to work properly.

Eventually, the brain struggles to cope with this damage and dementia symptoms develop.

Memory problems, thinking and reasoning difficulties and language problems are common early symptoms of the condition, which then worsen over time.

Dementia are expected to sky-rocket in the coming years, making a cheap screening tool vital to get to grips with the challenge.

Alzheimer's Research UK analysis found 74,261 people died from dementia in 2022 compared with 69,178 a year earlier, making it the country's biggest killer.