SN instructed patient on Humalog 75-25, stated that it is used along with a proper diet and exercise program to control high blood sugar in people with diabetes. This product is a combination of two man - made insulins: intermediate - acting insulin lispro protamine and rapid - acting insulin lispro. This combination starts working faster and lasts for a longer time than regular insulin. Insulin is a natural substance that allows the body to properly use sugar from the diet. It replaces the insulin that your body no longer produces, thereby lowering your blood sugar. Controlling high blood sugar helps prevent kidney damage, blindness, nerve problems, loss of limbs, and sexual function problems. Proper control of diabetes may also lessen your risk of a heart attack or stroke. SN also instructed that pain, redness, swelling or itching at the injection site may occur. These effects usually go away after a few days or weeks. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.