Metformin is a prescription medicine intended for the treatment of type 2 diabetes. It's most efficient when taken as recommended and combined with other medications only if your doctor thinks it is necessary. Take this drug exactly as prescribed and never exceed the dose recommended. If you happened to take too much of metformin and get symptoms like weakness, dizziness, vomiting, lightheadedness, discomfort, muscle pain, nausea, stomach pain, decreased appetite, or extreme tiredness, seek emergency medical help as those are the symptoms of an overdose. Make sure you report any serious side effects to your health care provider. However, in most cases you will get just a few mild ones - such as gas, runny nose, cough, headache, muscle pain, constipation, heartburn, diarrhea, bloating, flushing of the skin, metallic taste in mouth, sneezing, or stomach pain. Metformin side effects are usually mild and do not tend to last for too long - so there is no need for you to report them. You will need to report your side effects only if they get bothersome and interfere with your everyday life too much. Metformin is not expected to cure your diabetes - it will simply help you control the symptoms. You will need to continue taking it to feel fine.