Understanding Insulin

Insulin is a hormone that is released by the beta cells of the pancreas in response to a rise in the level of glucose in the blood. Blood glucose levels rise when a person consumes carbohydrate-containing food or drinks, as well as during periods of physical and sometimes mental stress. Insulin prevents a further increase in the blood glucose level and causes it to fall gradually by enabling the glucose to enter the body’s cells, where it is burned for energy or stored as glycogen or fat for later use. While many hormones raise blood glucose levels, only insulin lowers them.

Types of insulin:

  • Rapid-acting insulin begins to work about 15 minutes after injection, peaks in about 1 hour, and continues to work for 2 to 4 hours.
  • Example: Insulin lispro (Humalog), insulin aspart (NovoRapid)
  • Regular or Short-acting insulin: usually reaches the bloodstream within 30 minutes after injection, peaks anywhere from 2 to 3 hours after injection, and is effective for approximately 3 to 6 hours.
  • Example: Humulin R
  • Intermediate-acting insulin: generally reaches the bloodstream about 2 to 4 hours after injection, peaks 4 to 12 hours later, and is effective for about 12 to 18 hours.
  • Example: NPH (Humulin N)
  • Long-acting insulin reaches the bloodstream several hours after injection and tends to lower glucose levels evenly over a 24-hour period.
  • Example: Insulin detemir (Levemir) and insulin glargine (Lantus)

Insulin and Type of diabetes:

In Type 1 diabetes, an autoimmune process destroys the insulin-producing beta cells of the pancreas, leaving it unable to make insulin. People with Type 1 diabetes must, therefore, inject or infuse insulin for survival.

In Type 2 diabetes, some degree of insulin resistance is typically present. Initially, the pancreas may release more insulin than normal to compensate for the insulin resistance, but eventually, the pancreas is believed to “burn out” from overproduction, and blood glucose levels rise. In most cases, insulin resistance can be improved with moderate weight loss, so treatment recommendations generally include lifestyle adjustments such as changes in diet and increased physical activity. If dietary changes, increased physical activity, and oral medicines are unable to keep blood glucose levels adequately controlled, insulin therapy may be added to the diabetes treatment regimen or substituted for the oral drugs

5 important things you should know about insulin:

  1. Insulin isn’t the last resort.

You may be worried about starting insulin because you feel you have failed in controlling your disease, or you believe it is a sign your health is on a fast decline. Insulin is just another approach in managing diabetes. A lot of people think insulin is the last resort. But in some cases, it is the first therapy used in diabetes management.

  1. Insulin doesn’t have to hurt.

Unlike other diabetes medications, insulin must be injected to work. Some people are reluctant to take insulin because they are afraid of painful pokes. But it doesn’t have to hurt. Today’s insulin pens use such tiny needles which are pretty much painless. You can also rotate your site of injection – that is, avoid injecting into the same exact injection site you last used. This will help avoid scarring and reduce skin irritation and pain.


  1. Insulin isn’t so inconvenient.

Devices used to deliver insulin are simpler and more portable than in the past. Most people use pens, which are easy to carry around. Some even come preloaded with insulin cartridges.

  1. Insulin has improved dramatically.

Back in 1920s, insulin was made from the pancreatic tissue of pigs and cows. In fact, animals were used in the manufacture of insulin up until the 1980s. But today, insulin used to treat diabetes is very different. Most insulin is made by combining simple cells like bacteria with the human gene for producing insulin.



  1. Insulin needs to be handled with care.
  • Keep your insulin refrigerated. All insulin must be kept refrigerated when not in use. Once an insulin pen is opened or used, it should be kept at room temperature. It can remain in room temperature for 28 days (Levemir:42 days) after opening after which it should be thrown
  • Write the date on the insulin vial or pen on the day you open it or start keeping it outside the fridge. This will help you remember when to stop using it.
  • Do not keep in hot places. Do not leave insulin in a hot closed car. Heat makes insulin break down and will not work well to lower your blood sugar.
  • Do not keep in freezing places. Never store in a freezer. If insulin is frozen, do not use. You will not be able to inject the insulin if it is frozen. Do not use even after thawing. Freezing temperature will break down the insulin and then it will not work well to lower your blood sugar. Throw frozen insulin in the garbage.
  • Do not leave in sunlight. Light can make insulin break down and then it will not work well to lower your blood sugar.
  • Never use insulin if expired. The expiration date will be stamped on the vial or pen. Remember if not in the fridge, the date on the vial or pen does not apply.
  • Inspect your insulin before each use. Look for changes in colour or clarity. Look for clumps, solid white particles or crystals in the bottle or pen. Insulin that is clear should always be clear and never look cloudy.
  • Be aware of unusual or weird smells. Insulin should not have an odour or bad smell. If you can smell an odour do not use the insulin.


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