Rapid-Acting Insulin

This type of insulin, sold as Humalog, NovoLog and Apidra, begins to lower blood sugar in roughly 15 minutes, with it's sugar-lowering effects reaching their apex after about 60 to 90 minutes, and the effects lasting 4 to 5 hours. This kind of insulin should be taken just before meals.

Regular Insulin

This type of insulin, sold as Humilin R and Novolin R, also works relatively quickly, beginning to lower blood sugar approximately 60 to 90 minutes after injection, and peaking 2 to 3 hours after injection, with the effects lasting from 5 to 7 hours.

NPH

An intermediate insulin, sold as Humilin N and Novolin N, which begins to work about 2 to 4 hours after injection. It peaks after about 4 to 12 hours and lasts anywhere from 14 to 20 hours.

Insulin Glargine

Sold as Lantus, this form of insulin has a long-acting effect. It begins to work in roughly 1 to 2 hours, and lasts for 24 hours. Lantus has no peak effect and continually lowers blood sugar at a constant rate during it's effective period.

Mixing Insulin

Many use more than one type of insulin to control their blood sugar. For this reason, premixed combinations of regular and NPH insulin, in 70/30 and 50/50 mixes are available. These combination treatments provide the effects of both regular and NPH insulin injections, in one convenient dose.

Source:

Drugstore.com

More Information:

eMedTV