If you live with diabetes, insulin administration may feel like a standard aspect of daily life. If, however, you recently received a diabetes diagnosis and/or insulin prescription, you likely have many questions about this life-saving medication.

Insulin medications have been used to treat and manage diabetes for a little more than a century.

In the 1920s, insulin was extracted from the pancreas of cows and pigs to treat diabetic patients. Lab-produced synthetic insulin that closely mimicked natural pancreatic insulin (known as human insulin) was first developed in the early 1980s and widely used for decades. Today, new types of synthetic insulin, known as insulin analogs, have also become increasingly prevalent. Insulin analogs are similar to human insulin but have been engineered to impact the body in slightly different and more advanced ways.

Understanding your insulin needs and developing a treatment plan is something you will navigate with the support of your doctor or healthcare provider. Effective diabetes management is a highly individualized process, and many patients continually adapt their insulin usage to the changing needs and characteristics of their condition over time.

The information below provides an overview of insulin’s characteristics, the various types of insulin available, insulin administration, dosing, side effects, storage, and more. For further information about insulin as it pertains to your specific diagnosis, speak directly with your doctor.

Key Takeaways

  • Natural insulin is a hormone produced in the human pancreas that allows blood glucose to enter body cells and be metabolized into energy.
  • Many diabetic patients take synthetic insulin medications (human insulin or insulin analogs) to maintain healthy blood sugar levels.
  • Insulin medications are categorized by their onset, peak, duration, and concentration. The main types include rapid-acting insulin, short-acting insulin, intermediate-acting insulin, long-acting insulin, and pre-mixed insulin.
  • Insulin is often administered by injection, though other administration methods also exist. The drug’s dosing schedule is determined based on the individual needs of each patient.
  • Your doctor or healthcare provider will help you determine what type and dose of insulin is the best fit for your particular circumstances.

Insulin Characteristics

Insulin medications are defined and categorized according to several different characteristics. We’ve listed the main ones below and defined them in simple terms:

  • Onset – This refers to how quickly insulin acts in the body.
  • Peak – This refers to the length of time insulin takes to reach its maximum strength.
  • Duration – This refers to the length of time insulin takes to wear off.

In addition, insulin may also be categorized according to its concentration. In the U.S., most standard insulins have a concentration of 100 units per mL (also known as U-100), but it’s always important to double-check the concentration of any insulin you’re using for the first time to ensure you are receiving the correct dosage.

Types of Insulin

Your doctor or healthcare provider will tell you what type of insulin you are being prescribed and explain how to properly administer it. In some cases, patients may be prescribed a combination of different insulins and/or other antidiabetic medications to be used at different times throughout the day.

The different types of insulin include:

Rapid-Acting Insulin

Rapid-acting insulin (also known as fast-acting or mealtime insulin) covers mealtime insulin needs and can be taken at the same time you start eating a meal. It is often taken in combination with longer-acting insulin.

  • Onset: 5-30 minutes
  • Peak: 30-90 minutes
  • Duration: 1-4 hours

Rapid-acting insulin brand names include Humalog (insulin lispro), Novolog (insulin aspart), and Apidra (insulin glulisine).

Regular (Short-Acting) Insulin

Regular insulin (also known as short-acting insulin) covers mealtime insulin needs and should be taken 30-60 minutes before you start eating a meal.

  • Onset: 30 minutes to 1 hour
  • Peak: 1-5 hours
  • Duration: 2-8 hours

Short-acting insulin brand names include Novolin R and Velosulin (insulin pump only).

Intermediate-Acting Insulin

Intermediate-acting insulin covers insulin needs for approximately one-half of the day and is commonly used overnight. It may also be used in combination with a short-acting insulin.

  • Onset: 1-2 hours
  • Peak: 4-12 hours
  • Duration: 18-24 hours

Intermediate-acting insulin brand names include Humulin N and Novolin N.

Long-Acting Insulin

Long-acting insulin covers insulin needs for a full day or more and may be delivered at a steady level with no peak time. It is often prescribed in combination with short-acting insulin(s) for mealtimes.

  • Onset: 30 minutes to 2 hours
  • Peak: 6-8 hours (some types have no peak)
  • Duration: 20-42 hours

Long-acting insulin brand names include Basaglar, Lantus, and Toujelo (all insulin glargine), Levemir (insulin detemir), and Tresiba (insulin degludec).

Pre-Mixed Insulin

Pre-mixed insulins combine a short-acting insulin and an intermediate-acting insulin in a single dose. They are usually administered before meals two or three times per day.

  • Onset: 10-30 minutes
  • Peak: 30 minutes to 12 hours (dependent on the mix of insulins)
  • Duration: 14-24 hours

Pre-mixed insulin brand names include Humulin 70/30, Novolin 70/30, Novolog 70/30, Humulin 50/50, and Humalog Mix 75/25.

How Insulin Is Administered

Insulin is most commonly administered via subcutaneous injection (injection into the fatty tissue just below the skin). Many patients use needles and syringes, cartridge systems, or prefilled pens to inject insulin, but other administration options are also available. These include insulin pumps and insulin inhalers, which each have their own unique advantages and disadvantages.

Ultimately, the best insulin administration method for your particular needs is something to discuss with your doctor or healthcare provider. Some patients use a combination of administration methods (for instance, an insulin inhaler at mealtimes along with long-acting insulin injections once daily).

How Dosing Is Scheduled

Because every patient has unique needs and responds differently to insulin, the medication’s dosing is determined and scheduled on an individual basis. It’s also common for patients’ insulin dosing schedules to evolve and change over time as they live with diabetes.

You and your doctor will work together to monitor your blood sugar levels and ensure that your insulin-dosing schedule meets your health needs continuously. Maintaining a consistent insulin-dosing schedule is fundamental to managing diabetes and living a healthy, active life.

Insulin Side Effects

Like any medication, insulin is associated with possible side effects. The most well-known of these is low blood sugar (hypoglycemia), which can occur when insulin reduces blood glucose levels to a greater degree than intended. Symptoms of hypoglycemia can include:

  • Shakiness
  • Sweating
  • Disorientation/confusion
  • Rapid pulse
  • Dizziness
  • Loss of consciousness (in severe cases)

Mild hypoglycemia can usually be mitigated by consuming fast-acting carbohydrates and monitoring your blood sugar levels, but if you are regularly experiencing this condition, speak with your doctor about adjusting your insulin dosage and schedule. Severe hypoglycemia (also known as insulin shock) is considered a medical emergency and should always be treated with immediate medical attention.

Other side effects of insulin may include:

  • Injection site reactions
  • Weight gain
  • Headache
  • Edema (swelling of the arms and legs)

Storing and Disposing of Insulin

Injectable insulin should be stored in the refrigerator (between 36°F to 46°F) before being opened. Never allow insulin to freeze and do not inject insulin that has been frozen. Many patients prefer not to inject cold insulin, and most injectable insulins can safely be stored at room-temperature for approximately a month (be sure to read the manufacturer’s instructions). Take note of the insulin’s expiration date and keep the medication away from extreme temperatures and direct sunlight. Dispose of insulin immediately if it appears clumped, discolored, or otherwise irregular.

Used insulin syringes and pen needles should always be safely disposed of in an FDA-approved sharps disposal container. Check with your doctor and/or local municipality for further guidelines specific to your area.

What Type of Insulin Do I Need?

The type (or types) of insulin that your doctor prescribes for you will depend on a variety of factors including:

  • Your body’s response to insulin
  • Your age and lifestyle choices (diet, exercise, alcohol consumption, etc.)
  • Your health goals
  • Your ability/willingness to regularly inject insulin

You and your doctor will work together to determine the best type(s) of insulin for your specific needs. Always follow the recommendations of your doctor and take insulin exactly as prescribed.


To conclude, insulin is a life-saving medication that can enable people with various forms of diabetes to lead active, healthy lives. Many different types of insulin are available, and patients may take one or more of these regularly to control their blood sugar levels, as recommended by their doctor.

Often, rapid-acting or short-acting insulin is taken to cover mealtime blood sugar spikes in combination with intermediate-acting or long-acting insulin, which functions to keep blood glucose levels under control throughout the rest of the day and overnight. In addition, other non-insulin antidiabetic medications (such as Ozempic or Mounjaro) may also comprise an important aspect of diabetes management and treatment for some patients.

At Bisonpharmacy.com, we are dedicated to helping Americans access high-quality insulin and other antidiabetic medications at affordable prices. Our experienced team is here to answer any questions you may have and to ensure a professional and streamlined customer experience from start to finish. Contact us today to learn more and order insulin and/or other medications directly to your doorstep!

About the Author

Ida Edlweiss Gumpal is a licensed Pharmacist and medical writer. She took her internships at Mercury Drug Corporation, Inc., a Hospital internship at De Vera Medical Center, Inc., and a Manufacturing internship at Philmed Laboratories, Inc. She has plans on attending medical school with the goal of specializing in Neurosurgery or Cardiothoracic surgery.