Side Effects of Insulin

Side Effects of Insulin

People with Type 1 Diabetes, need one or more types of insulin, several times a day, and people with Type 2 Diabetes, in some cases may also require insulin in addition to treatment with oral medications. When people take insulin they should be aware of some of the side effects it may cause. If they occur, our recommendation is to immediately seek medical assistance.

Hypoglycemia or low blood glucose levels.

Hypoglycemia or low blood sugar level, is at the top of the list of side effects caused by insulin use. Hypoglycemia is a condition that occurs when blood sugar levels (glycemia) fall below normal levels, turning into a very dangerous situation, if these values decrease too much. This can cause unconsciousness, irreversible neurological damage and even death, if the problem isn’t reversed as soon as possible.

Fortunately, this situation can be easily and quickly reversed by ingesting fast absorption glucose sources such as sweets, sugary drinks, sugar sachets, syrup and glucose tablets or gels, among others. Thus, if insulin is used, it’s very important that you always, have fast absorbing glucose sources, be aware of the symptoms of Hypoglycemia, and take action as soon as you feel any of them.

Hypoglycemia symptoms can occur suddenly; these are: dizziness, cold sweats, confusion, pale complexion, hunger, lack of attention, lack of coordination, headaches, sweating, drowsiness, inappropriate responses, tremors, irritability and blurred vision.

The main goal should be to avoid or prevent Hypoglycemic episodes. Hypoglycemia occurs when too much insulin is injected, when exercising for too long, not eating enough, when skipping meals or snacks, and not eating at the scheduled times. For this reason, it’s very important to take the dose prescribed by your doctor, don’t do more physical activity than you should, and follow your nutritional plan and schedule as advised. A very useful tool to avoid Hypoglycemia is to check your blood sugar levels (glycemia) on a daily basis, especially if you plan to exercise, in which case, you should monitor your blood glucose levels before, during, and after exercising.


Other side effects caused by insulin use.

Below is a description of some of these adverse effects.

Atrophy or Lipoatrophy: Atrophy, also known as lipoatrophy (wasting of the fatty tissue located under the skin), usually occurs when one uses impure insulin, or when injection sites aren’t rotated.

Hypertrophy or Lipohypertrophy: (swelling or bulging of fatty tissue) appears due to insulin effects because it can facilitate fatty tissue formation on the skin, generating swollen and soft areas. It can also be caused by using the same needle or syringe more than once, and also, by not rotating the daily injection sites.

Atrophy and hypertrophy usually don’t present any redness or pain. If you have any of these dystrophies (atrophy and hypertrophy) it’s advisable for you to rotate injection sites daily, on your arms, abdomen, thighs and buttocks. Use a new needle for each injection and don’t use impure insulins. Be sure to use the new human or RNA insulins, which are characterized by a high purity percentage.

It’s very important to make sure not to inject in areas that have atrophy or hypertrophy, because it will make insulin action unpredictable, and could require twice the dose in some cases. Therefore, we recommend to check by touching the skin and ensuring there’s no bulging or sagging, and if so, don’t use that injection site until this disappears.


When a person begins to use insulin, they may get irritation and itching at the injection site. Generally, these reactions tend to disappear after a few weeks. However, nowadays, insulin is purer, reducing the incidence of allergic reactions. If insulin use gives you any allergies, be sure to use human insulin because these are purer.

Insulin allergy: Sometimes people with Diabetes can be allergic to insulin itself. These people need to be desensitized through injection therapy by progressively increasing the doses, i.e., they are injected with small amounts of insulin and, gradually, they increase the dose to the indicated dose. Tell your doctor if you have an allergic reaction to insulin.

Insulin resistance: For people with Type 1 Diabetes (insulin-dependent), insulin resistance occurs when their bodies create a lot of insulin antibodies from the insulin injected. The new insulins can reduce this problem.

For people with Type 2 Diabetes (non-insulin-dependent), obesity is usually the cause of insulin resistance. Maintaining a proper body weight, can help sensitize the cells so they can be more susceptible to insulin signals making the problem subside.

Although insulin can cause certain side effects, these can be solved with the help of your physician. Therefore, it’s very important to check if you have any of these side effects, and if you do, ask your doctor to find a solution, so you can use insulin without any problems, allowing you to enjoy a healthy, productive and happy life.


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