I had no adverse reaction to Metformin but some people do have negative reactions. If you have trouble with it you can ask for the slow release Metformin which is a little kinder on the system. Remember also, that Metformin has very little effect on blood glucose, it is prescribed to help with liver dumps, to give some protection to the organs and as a mild appetite suppressant. So it is up to you how you lower your blood glucose using your chosen dietary regime and excercise plan. Good luck.Next test in 3m been given metformin today