Everything a Person with Diabetes Needs to Know About Insulin

02 Sep 2025

Everything a Person with Diabetes Needs to Know About Insulin Insulin is a critical hormone for regulating blood sugar levels, and understanding its r...

Everything a Person with Diabetes Needs to Know About Insulin

Insulin is a critical hormone for regulating blood sugar levels, and understanding its role and management is essential for individuals with diabetes. This article will cover everything you need to know about insulin, from its functions to different types, administration, and common challenges. Whether you're newly diagnosed or looking to refine your knowledge, this guide provides a comprehensive overview of insulin therapy.

What is Insulin and Why is it Important?

Insulin is a hormone produced by the pancreas that allows glucose from the food we eat to enter cells and be used for energy. In people with diabetes, the pancreas either doesn’t produce enough insulin (Type 1 diabetes) or the body cannot effectively use the insulin it produces (Type 2 diabetes). This leads to elevated blood sugar levels, which can cause a range of health problems if not managed properly.

Related reading: The Beginner S Guide To Reading A Blood Sugar Range Chart

Why is insulin important?

  • Regulates blood glucose: Insulin acts like a key that unlocks cells to allow glucose in, maintaining healthy blood sugar levels.
  • Prevents hyperglycemia: Without enough insulin, blood sugar levels rise too high (hyperglycemia), leading to complications such as nerve damage, kidney damage, and heart disease.
  • Prevents ketoacidosis: In Type 1 diabetes, a lack of insulin can cause the body to break down fat for energy, producing ketones, which can lead to a dangerous condition called diabetic ketoacidosis (DKA).

Related reading: Hyperglycemia Uncovered How To Safely Lower High Blood Sugar

| Condition | Explanation | Role of Insulin | | :--------------------------- | :------------------------------------------------------------------------------------------------ | :-------------------------------------------------------------------------------------------- | | Type 1 Diabetes | The body's immune system destroys the insulin-producing cells in the pancreas. | Requires insulin injections to survive because the body makes little to no insulin. | | Type 2 Diabetes | The body becomes resistant to insulin and/or doesn't produce enough insulin. | May require insulin injections to manage blood sugar levels when other treatments fail. | | Gestational Diabetes | Diabetes that develops during pregnancy. | May require insulin injections if diet and exercise are not sufficient to control blood sugar. | | Other Diabetes Conditions | Diabetes may develop as a result of certain other medical conditions, medications, or genetic syndromes. | May require insulin depending on the condition. |

Different Types of Insulin

There are various types of insulin available, each working at different speeds and lasting for different durations. The type of insulin prescribed depends on individual needs, lifestyle, and blood sugar patterns.

Rapid-Acting Insulin

  • Onset: Starts working within 15 minutes.
  • Peak: Reaches maximum effect in 1-2 hours.
  • Duration: Lasts for 2-4 hours.
  • Examples: Insulin lispro (Humalog), insulin aspart (NovoLog), insulin glulisine (Apidra)
  • Usage: Taken before meals to cover the carbohydrate intake.

Short-Acting Insulin

  • Onset: Starts working within 30 minutes to 1 hour.
  • Peak: Reaches maximum effect in 2-3 hours.
  • Duration: Lasts for 3-6 hours.
  • Examples: Regular insulin (Humulin R, Novolin R)
  • Usage: Taken before meals; often used less frequently now due to the availability of rapid-acting options.

Intermediate-Acting Insulin

  • Onset: Starts working within 2-4 hours.
  • Peak: Reaches maximum effect in 4-12 hours.
  • Duration: Lasts for 12-18 hours.
  • Examples: NPH insulin (Humulin N, Novolin N)
  • Usage: Used for basal (background) coverage; typically taken once or twice a day.

Long-Acting Insulin

  • Onset: Starts working within several hours.
  • Peak: Has a relatively steady effect without a pronounced peak.
  • Duration: Lasts for 24 hours or longer.
  • Examples: Insulin glargine (Lantus, Basaglar, Toujeo), insulin detemir (Levemir), insulin degludec (Tresiba)
  • Usage: Provides basal insulin coverage; usually taken once a day.

Pre-Mixed Insulin

  • Description: A combination of two types of insulin, typically a rapid- or short-acting insulin mixed with an intermediate-acting insulin.
  • Examples: Humulin 70/30 (70% NPH, 30% Regular), NovoLog Mix 70/30 (70% Insulin Aspart Protamine, 30% Insulin Aspart)
  • Usage: Simplifies insulin regimens by providing both mealtime and basal coverage in one injection.

Related reading: Diabetic Diet Swaps To Help You Manage Blood Sugar Today

Choosing the right type and dose of insulin is highly individualized. Here is an illustrative table for a better understanding.

| Insulin Type | Onset | Peak | Duration | Usage | | :------------------ | :-------- | :-------- | :-------- | :-------------------------------------------- | | Rapid-Acting | 15 mins | 1-2 hours | 2-4 hours | Before meals | | Short-Acting | 30 mins | 2-3 hours | 3-6 hours | Before meals | | Intermediate-Acting | 2-4 hours | 4-12 hours| 12-18 hours| Basal coverage | | Long-Acting | Several hours | No peak| 24+ hours | Basal coverage |

Insulin Delivery Methods

Insulin can be administered through various methods, each with its advantages and considerations.

Syringes

  • Description: Traditional method using a needle and syringe to inject insulin.
  • Pros: Affordable and readily available.
  • Cons: Requires manual drawing of insulin, potential for dosing errors, and multiple injections.

Insulin Pens

  • Description: Pre-filled or refillable devices that deliver insulin via a dial-a-dose mechanism.
  • Pros: More convenient and discreet than syringes, easier to use, and can deliver precise doses.
  • Cons: More expensive than syringes, requires proper storage, and each pen contains a limited amount of insulin.

Insulin Pumps

  • Description: Small, computerized devices that deliver a continuous, controlled dose of insulin throughout the day.
  • Pros: Provides more precise insulin delivery, reduces the need for multiple daily injections, and can be programmed for different insulin needs.
  • Cons: More expensive, requires training and monitoring, and potential for pump malfunction or site infections.

Jet Injectors

  • Description: Devices that use high pressure to deliver insulin through the skin without a needle.
  • Pros: Needle-free, reduces anxiety associated with injections.
  • Cons: Can be painful, may cause bruising, and insulin absorption may vary.

Inhaled Insulin

  • Description: A rapid-acting insulin that is inhaled into the lungs.
  • Pros: Quick onset of action, convenient for mealtime insulin.
  • Cons: Limited to rapid-acting insulin, potential for lung-related side effects, and not suitable for everyone.

Administering Insulin: A Step-by-Step Guide

Whether you're using a syringe, pen, or pump, proper insulin administration is crucial for managing blood sugar levels effectively. Here’s a step-by-step guide:

Using an Insulin Pen

  1. Prepare the Pen:
    • Wash your hands.
    • Check the insulin type and expiration date.
    • Attach a new pen needle to the pen.
    • Prime the pen by dialing 2 units and injecting into the air to ensure the needle is working.
  2. Select the Dose:
    • Dial the correct dose as prescribed by your doctor.
  3. Inject the Insulin:
    • Clean the injection site with an alcohol swab.
    • Pinch the skin and insert the needle at a 90-degree angle.
    • Press the injection button fully and hold for 10 seconds to ensure the full dose is delivered.
    • Remove the needle and dispose of it properly in a sharps container.

Using a Syringe

  1. Prepare the Syringe:
    • Wash your hands.
    • Check the insulin type and expiration date.
    • Gently roll the insulin vial to mix (do not shake).
    • Clean the top of the vial with an alcohol swab.
  2. Draw the Insulin:
    • Pull back the plunger to draw air into the syringe, matching the dose you need.
    • Insert the needle into the vial and inject the air.
    • Turn the vial upside down and slowly pull back the plunger to draw the correct dose of insulin.
    • Check for air bubbles and tap the syringe to remove them.
  3. Inject the Insulin:
    • Clean the injection site with an alcohol swab.
    • Pinch the skin and insert the needle at a 45- or 90-degree angle (depending on your body size).
    • Push the plunger fully to inject the insulin.
    • Remove the needle and dispose of it properly in a sharps container.

Injection Sites

Common injection sites include:

  • Abdomen
  • Thighs
  • Upper arms
  • Buttocks

Rotating injection sites helps prevent lipohypertrophy (fatty lumps under the skin), which can affect insulin absorption.

Managing Blood Sugar Levels

Insulin management is closely tied to monitoring and maintaining stable blood sugar levels. Here are some critical considerations:

Regular Monitoring

  • Blood Glucose Meters: Use a blood glucose meter to check your blood sugar levels regularly. Follow your healthcare provider’s recommendations for testing frequency.
  • Continuous Glucose Monitoring (CGM): CGMs provide real-time glucose readings and trends, helping you make informed decisions about insulin doses.

Understanding Insulin-to-Carb Ratios and Correction Factors

  • Insulin-to-Carb Ratio: The amount of insulin needed to cover a specific amount of carbohydrates. This ratio helps determine the correct insulin dose for meals.
  • Correction Factor: The amount by which one unit of insulin will lower your blood sugar. This factor is used to correct high blood sugar levels.

Adjusting Insulin Doses

  • Work with Your Healthcare Provider: Adjusting insulin doses should be done under the guidance of your doctor or diabetes educator.
  • Keep a Log: Record your blood sugar levels, insulin doses, meals, and physical activity to identify patterns and make informed adjustments.

Common Challenges and Solutions

Living with diabetes and managing insulin can present various challenges. Here are some common issues and potential solutions:

Hypoglycemia (Low Blood Sugar)

  • Symptoms: Shakiness, sweating, dizziness, confusion, and hunger.
  • Causes: Too much insulin, skipped meals, excessive exercise.
  • Solutions: Consume 15-20 grams of fast-acting carbohydrates (e.g., glucose tablets, juice) and recheck blood sugar after 15 minutes.

Hyperglycemia (High Blood Sugar)

  • Symptoms: Increased thirst, frequent urination, blurred vision, and fatigue.
  • Causes: Not enough insulin, illness, stress, dietary indiscretions.
  • Solutions: Take additional insulin as directed by your healthcare provider and monitor blood sugar levels closely.

Dawn Phenomenon

  • Description: An early-morning rise in blood sugar levels due to natural hormonal changes.
  • Solutions: Adjust insulin doses, switch to a different insulin type, or modify eating habits.

Somogyi Effect

  • Description: Rebound hyperglycemia after an episode of hypoglycemia, often during the night.
  • Solutions: Adjust insulin doses and eating habits to prevent nighttime hypoglycemia.

Injection Site Issues

  • Problem: Lipohypertrophy (fatty lumps under the skin).
  • Solutions: Rotate injection sites regularly and avoid injecting into affected areas.

The Role of Diet and Exercise

Diet and exercise are integral to managing blood sugar levels and maximizing the effectiveness of insulin therapy.

Balanced Diet

  • Carbohydrate Counting: Learning to count carbohydrates can help you match your insulin doses to your food intake.
  • Healthy Foods: Focus on consuming whole grains, lean proteins, fruits, vegetables, and healthy fats.
  • Limit Sugary Drinks: Avoid sugary drinks, processed foods, and excessive alcohol consumption.

Regular Exercise

  • Benefits: Improves insulin sensitivity, lowers blood sugar levels, and promotes overall health.
  • Types of Exercise: Include both aerobic activities (e.g., walking, running, swimming) and strength training exercises.
  • Monitor Blood Sugar: Check your blood sugar levels before, during, and after exercise, and adjust insulin doses as needed.

Emerging Technologies and Treatments

The field of diabetes management is continually evolving, with new technologies and treatments emerging to improve insulin delivery and blood sugar control.

Artificial Pancreas Systems

  • Description: Closed-loop systems that automatically adjust insulin delivery based on continuous glucose monitoring data.
  • Benefits: Improved blood sugar control, reduced burden of diabetes management.
  • Examples: Medtronic MiniMed 670G, Tandem Control-IQ.

Smart Insulin Pens

  • Description: Insulin pens that track insulin doses and provide dose reminders.
  • Benefits: Improved adherence, better data tracking for healthcare providers.
  • Examples: InPen, Companion Medical InPen.

Novel Insulin Formulations

  • Description: Ultra-rapid-acting insulins and once-weekly insulin injections.
  • Benefits: Faster onset of action, reduced injection frequency.
  • Examples: Fiasp (ultra-rapid-acting), insulin icodec (once-weekly).

Final Thoughts

Managing diabetes with insulin can be complex, but with the right knowledge, tools, and support, you can live a healthy and fulfilling life. Regularly consult with your healthcare provider, stay informed about the latest advancements, and adopt healthy lifestyle habits to optimize your insulin therapy. By understanding your insulin, how to administer it correctly, and how to manage your blood sugar levels, you can take control of your diabetes and improve your overall well-being.