Metformin is a relatively inexpensive drug, commonly prescribed for the treatment of type 2 diabetes. It works by modifying the activity of pathways regulated by insulin, but interestingly, also modulates processes that are thought to underly ageing, including senescence, inflammation, mitochondrial function, epigenetic modification and telomere length. As such, there has been mounting interest in its potential anti-ageing properties.
Metformin can have a significant effect on ageing in animal models, with one study demonstrating a 40% increase in lifespan in worms. However, results from such research have been mixed: the effects of metformin are less pronounced in mice, and seemingly non-existent in fruit flies.
But what of the effects of metformin in humans? Research has suggested that metformin can slow cognitive decline, and lower risk of cancer. However, this does not mean that non-diabetics should be taking metformin. The majority of the aforementioned research is conducted in diabetics or prediabetics, and there is not enough data on the effects of metformin in healthy individuals to draw any firm conclusions.
Moreover, exercise and caloric restriction act through similar pathways to metformin, and offer greater health benefits. One study found that exercise was nearly twice as effective as metformin when it came to preventing progression of prediabetes, and there is also evidence that metformin actually counteracts some of the benefits of physical activity.
There is great appeal in a miracle pill that will slow ageing without any effort on our part. For the foreseeable future however, exercise, healthy eating, and abstinence from smoking are likely to remain the most potent pills available!