We’ve known it drops T. It’s used it the treatment of PCOS in women specifically for this purpose. I would say maybe it’s a factor for the natural folks… but for us? We’re manipulating that number anyway so health benefits of metformin still win.
VO2 max, was addressed by David Sinclair on multiple podcasts. If you have to perform high quality exercise or have high levels of performance output… simply take it after the event. The VO2 max dip has to do with the way it tricks the mitochondria into thinking the cell needs more mitochondria. Which In turn is enormous health benefit. He also goes onto to say, paraphrasing here, unless your competing in the Olympics, or a professional athlete etc…. You probably won’t notice a difference.