Humalog (insulin lispro) is a fast-acting insulin that starts to work about 15 minutes after injection, peaks in about 1 hour, and keeps working for 2 to 4 hours. Insulin is a hormone that works by lowering levels of glucose (sugar) in the blood. Humalog is used to treat type 2 diabetes in adults. Humalog is also used to treat type 1 diabetes in adults and children who are at least 3 years old.
How to take Humalog. Your doctor will determine how much Humalog you should take, how often, and with which meals. Not all insulin acts the same, or works at the same rate. Humalog is a fast-acting insulin, and its results do not last for long periods of time, because it’s meant to keep your blood sugar from spiking after you eat. For best results, use Humalog within 15 minutes before eating, or at the very beginning of your meal.