Yes, Humalog (insulin lispro) is a rapid-acting insulin analog.
Humalog is definitively classified as a rapid-acting insulin analog (RAA) with a quicker onset and peak and shorter duration of action than regular human insulin. 1, 2
Pharmacokinetic Profile
Humalog has the following time-action characteristics that define it as rapid-acting:
- Onset of action: 5-15 minutes after subcutaneous injection 3, 4
- Peak effect: 1-3 hours (most sources cite 1-2 hours for clinical purposes) 2, 4
- Duration of action: 3-5 hours (clinically 3-4 hours is most relevant for patient management) 2, 3, 4
These pharmacokinetic properties are achieved through a molecular modification where proline and lysine are reversed in the C-terminal portion of the B chain, which prevents self-association into hexamers and allows for more rapid absorption into the circulation. 5, 6
Clinical Classification Context
The American Diabetes Association explicitly categorizes insulin lispro (Humalog) as a rapid-acting analog (RAA), distinguishing it from:
- Short-acting insulin: Regular human insulin (slower onset, longer duration) 1
- Ultra-rapid-acting analogs (URAA): Newer formulations like Lyumjev (faster-acting insulin lispro) that have even more accelerated absorption profiles 1, 3
Clinical Implications
The rapid-acting profile means Humalog can be administered within 15 minutes before meals or even immediately after meals when food intake is unpredictable, unlike regular human insulin which requires 30-minute pre-meal administration. 7, 5, 6
The rapid onset combined with short half-life creates a critical safety consideration: hypoglycemia can develop quickly if food intake is delayed or inadequate after injection. 4
Humalog is recommended by the American Diabetes Association for use as prandial insulin in basal-bolus regimens and in continuous subcutaneous insulin infusion (insulin pumps) for both type 1 and type 2 diabetes management. 2