Insulin Side Effects | Adverse Effects of Insulin With Other Medicines

Medically Reviewed By DR. HARDIK BAMBHANIA, MBBS, MD October 15, 2023

Last updated on October 16th, 2023

Insulin – it’s that hormone that keeps many people with diabetes in the game, helping to maintain blood sugar levels and keep them in check. But here’s the scoop: even insulin isn’t immune to side effects. While the benefits of insulin are well-documented, it’s essential to understand and manage the potential adverse effects that may accompany its use. In this article, we will explore the various insulin side effects, ranging from common and mild to rare. But severe, providing you with valuable information to make informed decisions about your diabetes management. So, whether you know about insulin or you’ve just been diagnosed with diabetes, it’s essential to know the ins and outs of these side effects.

What Is Insulin?

Insulin hormone we believe you must be most familiar with when dealing with diabetes. It’s the insulin that makes your body transfer sugar or glucose from the bloodstream into different body cells. The cells then use the sugar for their normal functioning as fuel. In type 1 diabetics, the pancreas is simply unable to secrete or produce insulin. However, in type 2 diabetes, the body can’t secrete adequate amounts of insulin. Or simply cannot use it properly. When insulin is not put to use, the sugar will stay in the bloodstream, inflating sugar levels. 

To control the rising sugar levels, doctors can often prescribe external insulin. The external insulin is simply called insulin for convenience. There are many versions of this man-made insulin, including rapid-acting types, short & long-acting types, etc. This external insulin imitates your body’s reaction to food, as done by natural insulin. Thus bringing down the amount of sugar in the bloodstream or simply the blood sugar. However, you may experience side effects to insulin injections (external). In this blog, we will discuss that in detail.

Insulin And Side Effects

Side Effects of InsulinAs the insulin is artificially prepared in the lab, your body might experience some adverse effects of insulin. Below are some major injectable insulin side effects. However, they are general insulin drug side effects and may not include side effects that you may experience. For particular side effects of taking insulin, have a chat with your doctor. Insulin and side effects vary from person to person. 

Read More: How To Stimulate Your Pancreas to Produce Insulin Hormones in the Body? 


The insulin shot intended to make your sugar levels fall within the safe range may act more powerfully. This results in ultra-low blood sugar or hypoglycemia. According to Mayo Clinic, taking insulin or other medications can lead to hypoglycemia. In hypoglycemia, sugar levels fall even below 70 mg/dL. So insulin overdose side effects may have symptoms like:

  • Excessive sweat
  • Confusion
  • Shivering
  • Excessive hunger
  • Dizziness
  • Increased heartbeat

This is one of the top insulin disadvantages. And if you experience any of these signs, go for a blood sugar test immediately! After diagnosis, when you find side effects of high insulin follow the 15-15 rule. In this rule, you eat 15 grams of simple carbs or 3 to 4 glucose pills. It can also include ½ glass of any fruit juice or any aerated drink or simply 1 tablespoon of white sugar.

After 15 to 20 minutes, again check your blood sugar. If your sugar level is still below 70 mg/dL, repeat the process once more. Even after this, if the blood sugar doesn’t rise, seek medical help immediately. To prevent side effects of insulin therapy, finding the right dosage is of utmost importance. Your diabetologist will help you figure out the right dosage of insulin. The normal range of blood sugar (fasting) in diabetics is between 80 mg/dL and 140 mg/dL. The postprandial blood sugar in diabetics is less than 180 mg/dL. To avoid major side effects of insulin, you and the doctor can also engage in trial and error methods. 

Read More: Insulin Resistance Diet: What to Eat & What to Avoid

Weight Gain

Rapid or Lantus insulin side effects include weight gain as a major side effects of insulin therapy. Injecting insulin enables your cells to absorb extra sugar from the bloodstream. This sugar gets accumulated and converted into fats. Despite helping your body use insulin more effectively, it results in an increase in body weight. According to Diabetes UK, you’re more likely to gain weight if you take human or animal insulin. On average, people dependent on insulin put on more than 2 kg of weight. This is one of the long term side effects of insulin use. Insulin causes weight gain. Therefore, to prevent these insulin side effects, include in your schedule some diabetes-friendly diet plan

Along with this, start a daily session of muscle-building workouts. Gaining muscles will help you use the stored fats and also absorb sugar from the bloodstream. Therefore, if you are on insulin therapy and witness this, taking insulin side effects of weight gain at once, connect with your doctor. These lifestyle modifications suggested above will help you in influencing your sugar levels. Along with it, these will lower the chances of insulin medication side effects.

Read More: Types of Insulin Chart

Insulin Injection Side Effects

Other common injecting insulin side effects include discomfort, swelling, and redness at the injection site. Some symptoms include itching, redness and swelling. This happens due to multiple metallic injections at the same spot. However, this isn’t considered allergic side effects from taking insulin rather, it is irritation of the skin.

What’s good about this is injectable insulin side effects are not that concerning. To relieve yourself from this swelling and pain, you can apply ice packs, ointments and medicines like Benadryl. To lessen the pain and discomfort, change the spot of application. You also bring insulin at room temperature before application, cold insulin gives more pain.


Another side effects from Lantus insulin and other types is developing headaches. While fluctuations in blood sugar can lead to headaches. A momentous drop of insulin can also be the cause which is caused by an insulin shot. However, this definitely doesn’t mean that every time you have a headache, it is because of insulin glargine side effects. But you should know about it. For headaches, you can take any headache pill like Advil or Motrin. However, once you figure out the ideal dosage of insulin for you, these insulin uses and side effects will go away. The diabetes insulin injection side effects can become complex, and there can be multiple reasons involved. Always stay in touch with your doctor to monitor your health.


Lipodystrophy comes next on the list of side effects of insulin medication. In this, the distribution of fats in your body will get uneven. There are two kinds of lipodystrophy caused by the side effects of regular insulin usage. First is lipoatrophy, in which there is a loss of fat from the skin. Second is lipohypertrophy, which is an enlargement of fatty skin. This happens on the spot where insulin injection is injected. According to the National Institutes of Health, subcutaneous insulin injections can cause lipodystrophy. Therefore, changing your spot of insulin injection becomes necessary. Injecting areas with uneven fat distribution affects how well your sugar level is controlled in your body. Therefore, to avoid these side effects of insulin injection for diabetes, keep rotating the injection spots.


In commonly occurring side effects, lantus insulin now comes Edema. In edema, arms and legs get swollen up. Insulin has the ability to hold sodium and other fluids. As you are taking external insulin, this can lead to retaining excessive fluid, thus affecting your arms and limbs. According to Oxford Academic, it’s one of the rare insulin shot side effects, but having the knowledge of it is always beneficial. When treating edema the diabetologist will recommend some lifestyle modifications. These modifications will include leg and arm exercises and movements and limiting salt intake. If there are still no improvements in side effects on insulin, the doctor will further adjust the dosage. 

Read More: 15 Ways To Lower Your Insulin Levels Naturally

More Insulin Shot Side Effects

Apart from the above side effects of injecting insulin, there are also other insulin side effects on kidney, heart, veins, etc. As per the NHS, insulin can cause the following side effects:

  • Blurred vision
  • Stuttering
  • Tingling sensation in palms, lips, tongue, etc
  • Anxiety
  • Mood changes and swings
  • Shakiness
  • Increase in thirst
  • Increase in hunger
  • Swelling in spots
  • Sleepiness 
  • Weakness
  • Bad dreams
  • Seizures
  • Loss of consciousness
  • State of confusion
  • Emotional outburst
  • Drop in blood potassium (hypokalemia)
  • Muscle cramps
  • Breathing problems
  • Allergic reactions

Considering other long term side effects of insulin use there are heart ailments, too. The symptoms include:

  • Breathing difficulty
  • Swelling in ankles
  • A sudden increase in weight

Read More: How to Reverse Prediabetes Naturally?

Adverse Effects of Insulin on Interaction with Other Medicines

Insulin drug side effects can also occur when insulin reacts with other kinds of medicines you take. Each interaction will result in different results, like aggravating insulin shot side effects. Or simply interfering with the efficacy of other medicines you take. Below are the possible insulin and side effects that are bound to happen:

Other Diabetic Medications

As per the findings of NLM, taking thiazolidinediones along with insulin can result in fluid retention and heart stroke. Examples of such medicines are:

Taking these along with taking insulin side effects may go towards hypoglycemia. Therefore, always consult with a doctor before taking both.


Intake insulin injection side effects include causing hypoglycemic sugar levels when taken with antidepressants. Examples include fluoxetine and MAOIs.

High BP Medicines

Blood pressure pills with insulin shots result in low B.P.

Taking blood pressure pills along with insulin shots can result in making BP levels extra low. To remove these side effects of taking insulin, a doctor’s consultation is mandatory. The drug examples include:

  • Lisinopril
  • Captopril
  • Enalapril
  • Valsartan
  • Propranolol
  • Metoprolol, etc.

Read More: Is Type 2 Diabetes Curable?

Heart And Cholesterol Medicines

Taking heart medicines like disopyramide with insulin may cause low blood sugar levels. According to the Sage Journals, disopyramide-induced hypoglycemia can be life-threatening. However, taking cholesterol drugs like Niacin may increase BP levels. To remove these adverse effects of insulin, always reveal to your doctor your dependence on such meds. Other heart ailment medicines which can get disturbed are:

  • Beta-blockers
  • Guanethidine
  • Reserpine
  • Clonidine

Specific Antibiotics

According to the NIH, taking these antibiotics along with insulin shots can result in sugar level fluctuations. Examples include:

  • Pentamidine
  • Sulfonamide antibiotics

Pain Relieving Drugs 

Taking drugs like aspirin with insulin may result in a dip in sugar levels. 

Blood Thinning Medicines

Major side effects of insulin cause hypoglycemia. However, when taking blood thinning meds like pentoxifylline, this can happen, too. 

Asthma And Allergy Meds

Taking insulin shots with asthma and anti-allergic medicines can increase sugar levels. These medicines include:

  • Corticosteroids
  • Sympathomimetic agents

Read More: 15 Foods To Lower Blood Sugar Levels

Precautions To Take to Avoid Side Effects of Injecting Insulin

Switching to insulin comes with specific precautions to be taken by different individuals.

People with Kidney Problems

As stated by Clinical Diabetes and Endocrinology, insulin side effects on kidney-related diseased individuals are high. Insulin is secreted out by the body with the help of the kidney. When the kidney is not working well, insulin gets deposited in the body. This causes a greater decrease in blood sugar than required. Therefore, with kidney patients, the doctor may adjust the insulin dosage accordingly.

People With Liver Ailments

Lantus insulin side effects are greater in liver patients. When there is liver failure, there is insulin accumulation in the body. The doctor may accordingly balance the dosage initially and then gradually increase it. 

Read More: 10 Best Glucometers in India

People With a History of Heart Attacks

Side effects of taking insulin are greater in heart patients. Taking medicines like thiazolidinediones (TZDs) with insulin may deteriorate your heart condition. So, always tell your doctor about your heart condition when switching to insulin therapy.

People with Hypokalemia

Another side effects to insulin injections is that it causes fluctuations in potassium levels. Insulin may lower blood potassium levels in the body. So, if you are on potassium-lowering medications, seek medical help. 

Allergic Reactions

Allergic Reactions to Insulin

Some individuals can be allergic to external insulin. These side effects on insulin allergic individuals can be like:

  • Itching
  • Breathing problems
  • Skin rashes
  • Chest stiffness
  • Sweating
  • Swelling in face, lips, tongue, etc.
  • Rise in heart rate

Read More: What Is Type 2 Diabetes Management?

When To Seek Medical Help On Side Effects On Insulin Injection?

Many insulin side effects can be resolved once the body gets accustomed to insulin. However, if the side effects persist after a couple of weeks, it’s high time to consult your doctor. A doctor will be able to devise a perfect suitable insulin dosage according to your body. However, never take insulin shots without a doctor’s prescription. Or you may do more bad than good. 

Insulin and side effects can vary, and different insulin types will have different side effects. We suggest you discuss in detail all your body conditions before starting the course of any type of insulin in your body. 

Read More: What Is Sliding Scale Insulin Therapy Chart For Diabetics


In conclusion, our fellow diabetes warriors, we’ve taken a deep dive into the world of insulin side effects. While it’s true that insulin can be a game-changer in diabetes management, it’s not all sunshine and rainbows. From the occasional bumps in the blood sugar and pressure to rise in them. But here’s the thing: knowledge is power. By being aware of these potential side effects, you’re already one step ahead in managing your diabetes like a pro. It’s all about striking that balance between reaping the benefits of insulin and dealing with any curveballs it might throw your way. In the end, insulin might have its quirks, but it’s also a lifesaver. So, keep rocking those blood sugar levels, stay healthy, and continue living your best life, one finger prick at a time.

FAQ’s(Frequently Asked Questions)

How many units of insulin is normal?

Normally, to avoid side effects to insulin injections, 1 gram of rapid-acting insulin is fine. The general measurement is 12 to 15 grams of carbs consumption per 1 g of insulin. However, this measurement will differ according to your body weight and your response to insulin. Therefore, consult your diabetologist before taking insulin.

Can insulin cause health problems?

When talking of insulin disadvantages, insulin, if taken without proper monitoring, can cause side effects like:
Swelling in arms and legs
Weight gain
Skin problems
Uneven fat distribution

Is insulin harmful to kidneys?

Yes, insulin side effects on kidney are many. A perfectly functioning kidney will efficiently rinse out insulin if taken under a doctor’s supervision. However, kidney patients should be cautious when they are about to take insulin shots.

What are the negative effects of insulin?

Insulin drug side effects are many. But here are some common negative side effects of insulin:
Blurred vision
Increase in heartbeat
Tingling in hands, feet, tongue, etc.
Increase in hunger

What is the most serious side effect of insulin?

Hypoglycemia is among the top side effects on insulin. Hypoglycemia occurs in around 16% of type 1 diabetics and 10% of type 2 diabetics. Therefore, it’s very important to consult with your doctor before figuring out the insulin dose.

Last Updated on by Dr. Damanjit Duggal 


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