That article discusses the earlier experiments on nematodes and mice and doubts the applicability to humans of some results. This new study provides data about

That article discusses the earlier experiments on nematodes and mice and doubts the applicability to humans of some results. This new study provides data about positive results in primates, so it removes some of the earlier objections. Nevertheless, it is not clear yet whether the risks of harmful effects of long-term treatment with high doses of metformin do not outweigh its beneficial effects. Where I agree with the article linked by you is that metformin is not the actual cause of lifespan extension, but it mimics the effects of some other primary cause, perhaps calorie restriction. Therefore, the studies on the metformin effects should concentrate on establishing which is the mechanism of its action, even if that is much more difficult than just establishing a correlation between metformin intake and ageing. When the mechanism of metformin action will be understood, it is likely that the same effects will be achievable in safer ways.