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Insulins

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When Does My Insulin Peak and How Long Does It Last?

This table gives the start, peak, and end times for various insulins to help you choose which insulin you need to achieve your blood sugar goals. Humalog and NovoLog insulins start working in about 10 to 20 minutes. They can be taken immediately before eating, keep the blood sugar lower after meals, and are gone in about 4 hours. They balance meals better and improve control with fewer lows than Regular insulin.

Action Times for Insulins
Insulin Starts Peaks Ends Low most likely at:
Hum/Nov 10-20 m 1.5-2.5 h 4-5 h 2-5 h
Regular 30-45 m 2-4 h 5-7 h 3-7 h
NPH 1-3 h 4-9 h 14-20 h 4-16 h
Lente 2-4 h 8-14 h 16-24 h 6-16 h
UL 2-4 h 8-14 h 18-24 h 8-18 h
Lantus* 1-2 h 6 hr 18-26 h 5-10 h
Detemir* 1-3 h 8-10 18-24 h 8-16 h
* Lantus and Detemir have little peak, so lows are less likely unless dose is excessive.

Regular starts in about 30 minutes and keeps working for 5 to 8 hours after an injection. Most meals raise the blood sugar for only 2 hours, so Regular tends to let the blood sugar rise, with blood sugar drops seen long after a meal ends. Regular works better for slow carbs and for those who have gastroparesis (delayed digestion).

The figure below shows how long after an injection a low blood sugar is most likely to occur with each type of insulin.

Pumping Insulin provides much more pump information and is the most helpful book ever written on insulin use.

Using Insulin takes you step by step toward excellent control. Whether you use one injection and pills, or six injections, you'll learn far more from this book than from any other!