Metformin is the first-line medication prescribed for Type 2 Diabetes (the type caused by insensitivity to insulin). There are indications that it could also be linked with longevity. Patients taking metformin tend to be at low risk for certain age-related diseases such as non-alcoholic fatty liver disease and certain types of cancer. Diabetic patients, who have a lower lifespan than non-diabetics but who are on metformin tend to have a relatively higher life-expectancy as expected given their disease.

The drug has also been shown to be linked with increased lifespan in some types of rats, mice, and nematodes, also known as roundworms (insects resembling, but unrelated to, actual worms).

By lowering blood sugar levels metformin mimics a condition known to be linked with increased lifespan, that of restricted-calorie diets. Metformin also has to do with breakdown of certain amino acids (building blocks of protein) and with the balance of energy production in mitochondria (powerhouses of cells). Researchers at Ghent University in Belgium showed that this was the mechanism involved in metformin’s influence on longevity in nematodes. Researchers at the National Institutes of Health in the United States found similar results studying the effects of metformin on male mice. Mice given the medication had lowered cell damage and inflammation related to aging.

So, should we all be taking metformin to nudge our life spans into the three digits? This remains to be seen. Research involving human beings has not been fully conclusive yet and is therefore not routinely recommended. More research is needed to solve this question—but the medication certainly has some promise.