Humulin N is the brand name for human isophane insulin, an insulin substitute used to treat diabetes, which was approved by the FDA in 1982. Isophane insulin is a prescription medication which is available as a generic and under brand names like Humulin N and Novolin N. This intermediate-acting synthetic insulin has a structure that is almost identical to natural human insulin. When isophane insulin is injected, it passes into the blood and allows blood sugar, or glucose, to be transferred from the blood stream into the body's cells to be used as energy. This results in reduced blood sugar levels. The drop in blood sugar that results from synthetic insulin makes it a good choice for treating Type 1 diabetics. Isophane insulin is intermediate-acting, which means it starts working about an hour and a half after injection and reaches peak efficacy between four to eight hours later. Humulin N must be injected into the body. Dosages vary depending on your doctor's assessment of your insulin needs. Intermediate-acting insulin should be shaken or rotated so that the product looks uniformly cloudy. Do not use synthetic insulin if the white material remains at the bottom of the vial after mixing. Insulin injections can cause irritation or redness at the insertion site and can result in low or high blood sugar levels, causing dizziness or confusion. Ask your doctor for a complete list of side effects. Remember: tell your physician immediately if you experience fruity breath, rapid breathing, fainting or any other significant changes. Isophane insulin should not be taken by people with allergies to insulin products and insulin use should be monitored carefully in people with kidney or liver disease. Ask your doctor for a full list of medications and conditions that should not be combined with isophane insulin. Humulin N can be useful for controlling blood sugar levels. However, this medication should always be used under the direct care of a physician. Please ask for and review all of the patient information provided by your doctor before taking isophane insulin. The information in this video is intended to supplement, not substitute for, the expertise of your physician. Always consult your doctor before using this drug.