Thank you for writing to us, Brief Answer- headaches for the first couple days and leg cramps. Detailed Answer- HCG drops has these side effects like headaches for the first couple days and leg cramps. Both of these effects are from the low calorie diet and your body detoxing and can be fixed easily. First, for the headache that’s just your body detoxing from all the bad food that you have been eating before the diet. It is leaving your body because you are drinking so much water and your body is feeding off of your stored fat which has these bad chemicals stored in your body. But don’t worry, it only last a day or two and you can take a headache medication to help with any discomfort. Now onto the leg cramps. Leg cramps are common while on the diet and that’s from a lack of potassium. You can’t eat bananas while on the diet so in order to fix this you take a simple potassium supplement and that always solves the problem.