Metformin: From French Lilac to Cornerstone of Diabetes Care — Origins, Mechanism and Expanding Uses

Original publisher: Nature

Metformin's journey from a plant-based remedy to a global diabetes cornerstone is traced here, detailing its mechanism, clinical impact, and potential beyond glucose control. The piece also discusses safety considerations and evolving treatment guidelines, including the 2026 NICE update.

• Origin and historical role in type 2 diabetes
• Biguanide mechanism and AMPK activation
• Off-label uses for PCOS and potential in ageing and neuroprotection
• Guideline shifts toward earlier combination therapy with SGLT-2 inhibitors

Origins and clinical history

Metformin's story begins in galega officinalis, the French lilac, and spans decades of research that culminated in its introduction in the UK in the late 1950s. Metformin's strong claim to influence medicine is underscored by its role in diabetes care and its influence on research into ageing, cancer, and heart health.

"Metformin has a strong claim to being one of the most influential medicines of the past century." - Nature

Mechanism of action: AMPK activation and metabolic effects

Metformin is a biguanide drug that lowers blood sugar by improving insulin use, reducing hepatic glucose production via gluconeogenesis, enhancing glucose uptake in muscles, and limiting intestinal glucose absorption. It activates AMPK, the cellular energy sensor, which contributes to these effects.

"AMPK, often described as the cell’s energy sensor." - Nature

Beyond diabetes: potential uses and evidence

The article notes metformin's off-label use for PCOS, its potential effects on ageing and dementia, and possible neuroprotection with long-term use, though evidence remains mixed and further trials are needed. It stresses medical oversight and the need for robust clinical trials to confirm benefits beyond glycemic control.

"Metformin has also been studied for its possible effects on ageing and longevity." - Nature

Safety, side effects, and monitoring

Common side effects include nausea, stomach discomfort, diarrhoea, taste changes and loss of appetite; these may improve over time or with slow-release formulations, and taking with food can help. Vitamin B12 deficiency is a recognized issue, potentially leading to anaemia or neuropathy. Lactic acidosis is rare but serious, prompting monitoring in people with kidney or liver impairment and procedural precautions.

"The most common are nausea, stomach discomfort, diarrhoea, changes in taste, and loss of appetite." - Nature

Guidelines and the future of metformin in personalised care

The NICE guidelines in 2026 mark a shift toward earlier and more intensive treatment, recommending an SGLT-2 inhibitor alongside metformin from the start to protect heart and kidneys, reflecting a move toward personalized regimens while preserving metformin as a foundation.

"In 2026, however, the National Institute for Health and Care Excellence (Nice) updated its guidelines for type 2 diabetes, signalling a move towards earlier and more intensive treatment." - Nature

Conclusion

Metformin may be old, but its story continues as medicine becomes more personalized and integrated with new therapies, maintaining its status as a reliable, affordable foundation.