Metformin, used worldwide to treat Type 2 diabetes (in which the body does not appropriately respond to insulin in the bloodstream, leading to excessive amounts of insulin in the blood), may be one of the most prescribed drugs for this condition. This drug doesn't just treat the insulin; unlike most drugs, this one also helps prevent many of the cardiovascular problems associated with the hormonal imbalances of diabetes. It is also commonly used to treat polycystic ovarian disorder and metabolic syndrome, two disorders still not completely understood. A new study released in Nature Communication this month revealed that when fed in very low doses to middle aged mice, metformin actually did more. This drug seemed to mimic the effects of a low-calorie diet; namely, it increased the lifespan of the mice in the experimental group. However, in higher doses, metformin did enough kidney damage to significantly shorten lifespans - in fact, it shortened lives by more than the lower dose lengthened them.
It's still an interesting result, and it's worth remember that studying animal models allow us to discover which paths are worth pursuing in human models, with all the risks that entails, in a safer, faster, more humane manner.