National Geographic : 2012 Apr
Learn more at UnderstandBloodSugarControl.com or call 1.866.923.0210. Important Safety Information About Insulin: The most common side effect of insulin is low blood sugar. Some people may experience symptoms such as shaking, sweating, fast heartbeat, and blurred vision, while some experience no symptoms at all. That's why it's important to check your blood sugar often. Talk to your doctor about whether insulin is right for you.