Lantus is a long-acting insulin analogue also known as insulin glargine. Similar to human insulin, it is produced using recombinant DNA techniques. Insulin glargine substitutes glycine for asparagine at position A21 of the insulin molecule and adds two arginine molecules at position B30. The isoelectric point of insulin glargine is close to a pH of 7.0. Altering these amino acids makes insulin glargine precipitate in subcutaneous tissue. Zinc is added to stabilize intrahexamer contact to prolong activity.

Lantus is given subcutaneously as a depot injection. The onset of action is 2 to 4 hours. There is no peak action. The duration of action is 20 to 24 hours. With a long duration of action, Lantus lends itself to once-a-day dosing in the morning—an attractive formulation for those not critically ill.