The difference in blood sugar drop between 1 unit of regular insulin (R) and 1 unit of rapid-acting insulin lies primarily in their onset, peak action, and duration, rather than their blood sugar-lowering potential per unit. Here’s how they compare:
- Regular Insulin (R):
Onset: Begins working in 30-60 minutes after injection.
Peak Action: Peaks in 2-4 hours.
Duration: Lasts for 5-8 hours.
Blood Sugar Drop: Typically lowers blood glucose by about 30-50 mg/dL per unit, but the effect is slower and more prolonged.
- Rapid-Acting Insulin (e.g., Lispro, Aspart, Glulisine):
Onset: Begins working in 10-15 minutes after injection.
Peak Action: Peaks in 30-90 minutes.
Duration: Lasts for 3-5 hours.
Blood Sugar Drop: Also lowers blood glucose by about 30-50 mg/dL per unit, but it works faster and clears from the system more quickly.
Key Differences:
Timing: Rapid-acting insulin has a much faster onset and peak compared to regular insulin. It is often used right before or during meals to control post-meal blood sugar spikes, whereas regular insulin is typically used 30-45 minutes before meals due to its delayed onset.
Flexibility: Rapid-acting insulin provides more flexibility in meal timing since it works quickly, while regular insulin requires more planning.
Duration: Regular insulin stays active longer, increasing the risk of delayed hypoglycemia compared to rapid-acting insulin.
Practical Impact:
The blood sugar drop per unit is similar, but the timing of the drop differs. The faster action of rapid-acting insulin makes it better suited for quick corrections or meal-related spikes, while regular insulin may be more appropriate for longer-acting needs.