Half-Life of Humalog (Insulin Lispro)
The elimination half-life of insulin lispro (Humalog) is approximately 44 minutes following intravenous administration, with a clearance of 32 L/hour. 1
Pharmacokinetic Profile
The FDA label for LYUMJEV (insulin lispro-aabc), which shares the same active moiety as Humalog, provides the most precise pharmacokinetic data: 1
- Median half-life: 44 minutes (following 15 unit IV bolus in healthy subjects) 1
- Clearance: 32 L/hour (geometric mean, CV 22%) 1
- Volume of distribution: 34 L (geometric mean, CV 30%) 1
Clinical Pharmacodynamics
While the elimination half-life is under one hour, the clinical duration of action is 3-4 hours after subcutaneous injection, which is what matters for patient management. 2
Key time-action characteristics for subcutaneous administration: 2
Absorption Characteristics
After subcutaneous injection, insulin lispro demonstrates: 1
- Appearance in circulation: Approximately 1 minute after injection 1
- Time to 50% maximum concentration: 13 minutes 1
- Time to maximum concentration (Tmax): 57 minutes 1
- Absolute bioavailability: Approximately 65% (abdomen, deltoid, thigh) 1
Clinical Implications
The rapid elimination half-life and short duration of action provide important clinical advantages: 3, 4
- Better matching of insulin action to postprandial glucose excursions 3
- Reduced risk of delayed hypoglycemia, particularly nocturnal episodes 3, 5
- Ability to inject immediately before or even after meals (within 15 minutes) 3, 6
Important Caveats
Patients must understand that the rapid onset (5 minutes) combined with the short half-life means hypoglycemia can develop quickly if food intake is delayed or inadequate. 2, 7 This is a critical safety consideration distinguishing lispro from regular human insulin, which has a slower onset of 15 minutes and longer duration of 6-8 hours. 2
Day-to-day variability in pharmacokinetics is relatively low: 1