Full muscles can be achieved if 500-1000 mg are taken within 1 hour after a large carbohydrate meal. The more carbohydrates there are in the meal, the higher the dosage should be taken, you should never exceed 1500 mg at a time. At least 100 grams of carbs must be taken for every 500mg of Metformin used or you could experience hypoglycemic symptoms. Nevertheless, Metformin can be taken with as many high-carb meals as you wish. The half-life is 4-6 hours.