There&#x27;s no doubt about it that metformin does lower your BG. Depending on the person though the side-effects can be pretty nasty. Personally I had a lot of stomach problems (which I&#x27;ve never had before or since) and I found that I was unable to exercise because I would have a hypo after just 10 minutes. I also had trouble staying awake, I&#x27;d often be slumped in my chair and would need to take a 20min siesta after lunch. I&#x27;m a fit 36 year old who&#x27;s used to exercising a lot and having good energy levels so I found this situation difficult to get used to.