Lantus (generic: insulin glargine) is a prescription medication used to treat type 1 and type 2 diabetes. Lantus, a long-acting form of insulin, works by replacing the insulin that is normally produced by the body and by helping the body to use sugar for energy. It also stops the liver from producing more sugar.

This medication comes in an injectable form and is usually used once daily.

Common side effects of Lantus include low blood sugar, redness and skin thickening at the injection site, and weight gain.