Generic Name: Insulin Brand Name(s): Generics only. No brands available.

Know the basics

What is insulin used for?

If your blood sugar levels are higher than normal, insulin helps store the sugar in your liver and releases it when your blood sugar levels are low or when your body need more sugar, such as in between meals or during physical activity. Therefore, insulin helps balance out blood sugar levels and keeps them in a normal range.

Various types of insulin are used to treat diabetes, including:

  • Rapid-acting insulin:
    • It starts working approximately 15 minutes after injection and peaks at approximately 1 hour but continues to work for two to four hours.
    • This is usually taken before a meal and in addition to a long-acting insulin.
    • Types: Insulin glulisine (Apidra), insulin lispro (Humalog), and insulin aspart (NovoLog).
  • Short-acting insulin:
    • It starts working approximately 30 minutes after injection and peaks at approximately 2 to 3 hours but will continue to work for three to six hours.
    • It is usually given before a meal and in addition to a long-acting insulin.
    • Types: Humulin R, Novolin R.
  • Intermediate-acting insulin:
    • It starts working approximately 2 to 4 hours after injection and peaks approximately 4 to 12 hours later and continues to work for 12-18 hours.
    • It is usually taken twice a day and in addition to a rapid- or short-acting insulin.
    • Types: NPH (Humulin N, Novolin N).
  • Long-acting insulin: 
    • It starts working after several hours after injection and works for approximately 24 hours.
    • If necessary, it is often used in combination with rapid- or short-acting insulin.
    • Types: Insulin detemir (Levemir) and insulin glargine (Lantus).

How should I take insulin?

Insulin is injected just under the skin. Your doctor or his or her office staff will show you how and where to give an insulin injection. The usual places to inject insulin are the upper arm, the front and side parts of the thighs, and the abdomen. Don’t inject insulin closer than 2 inches from your belly button.

To keep your skin from thickening, try not to inject the insulin in the same place over and over. Instead, rotate injection places.

How do I store insulin?

Take steps to store your insulin correctly, or it might not work.

  • Keep your insulin away from heat and light. Any insulin that you don’t store in the refrigerator should be kept as cool as possible (between 13°C and 26°C).
  • Never let your insulin freeze. If your insulin freezes, don’t use it, even after it’s thawed.
  • Keep unused bottles, cartridges, and pens of insulin in the refrigerator (between 2,2°C and 7,8°C). If stored properly, these will be good until the expiration date listed on the insulin.
  • Keep insulin cartridges and pens that you’re currently using at room temperature (between 13°C and 26°C).

Know the precautions & warnings

What should I know before using insulin?

Before using insulin, tell your doctor and pharmacist:

  • If you are allergic to insulin, any of the other ingredients or medications.
  • What prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take.
  • Having nerve damage caused by your diabetes or any other medical conditions, including kidney or liver disease.
  • If you are pregnant, plan to become pregnant, or are breastfeeding.
  • You are having surgery, including dental surgery.
  • If you get sick, experience unusual stress, or change your exercise and activity level.

Is it safe during pregnancy or breastfeeding?

There are no adequate studies in women for determining risk when using insulin during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking insulin. Insulin is pregnancy risk category B according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk;
  • B=No risk in some studies;
  • C=There may be some risk;
  • D=Positive evidence of risk;
  • X=Contraindicated;
  • N=Unknown.

Know the side effects

What side effects can occur from insulin?

Hypoglycemia is the name for a condition in which the level of sugar in your blood is too low. When you use insulin, your blood sugar level can get too low if you exercise more than usual, if you don’t eat enough, if you don’t eat on time or if you take too much insulin. Most people who take insulin have insulin reactions at some time. Signs of an insulin reaction and hypoglycemia include the following:

  • Feeling very tired;
  • Yawning frequently;
  • Being unable to speak or think clearly;
  • Losing muscle coordination;
  • Sweating;
  • Twitching;
  • Having a seizure;
  • Suddenly feeling like you’re going to pass out;
  • Becoming very pale;
  • Losing consciousness.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Know the interactions

What drugs may interact with insulin?

Insulin may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Some of the medicines that may cause dangerously low blood sugar with symptoms such as dizziness, hunger, or sweating when combined with insulin include:

  • Alcoholic beverages;
  • Angiotensin-converting enzyme inhibitors (ACE inhibitors): lisinopril, quinadril, captopril, enalapril;
  • Beta-blocker medications, such as: metoprolol, propranolol, glaucoma eye drops such as timolol;
  • Disopyramide;
  • Fibrate cholesterol medications;
  • Sulfonamide antibiotics, such as: Sulfadiazine, Sulfamethoxazole;
  • Salicylates, such as: Aspirin;
  • Monoamine oxidase inhibitors (MAOIs), such as: Isocarboxazid, phenelzine;
  • Other medications: Octreotide, Oral diabetes medications, Propoxyphene, Reserpine.

Does food or alcohol interact with insulin?

Insulin may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with insulin?

Insulin may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.

Understand the dosage

The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using insulin.

What is the dose of insulin for an adult?

Rapid-acting insulin (insulin glulisine)

Usual range: 0.5-1 units/kg/day.

Short-acting insulin (Humulin R)

Type 1 Diabetes

  • Initial: 0.2-0.4 units/kg/day.
  • Maintenance: 0.5-1 unit/kg/day; in insulin-resistant patients (e.g, due to obesity), substantially higher daily insulin may be required.

Type 2 Diabetes

Suggested beginning dose of 10 units/day (or 0.1-0.2 unit/kg/day).

Intermediate-acting insulin (Humulin N)

Type 1 Diabetes

  • Suggested guidelines for beginning dose.
  • Usual daily maintenance range is 0.5-1 unit/kg/day; nonobese may require 0.4-0.6 unit/kg/day; obese may require 0.8-1.2 units/kg/day.

Type 2 Diabetes

  • Suggested guidelines for beginning dose: 0.2 unit/kg/day.
  • Morning: give two thirds of daily insulin and ratio of regular insulin to NPH insulin 1:2.
  • Evening: give one third of daily insulin and ratio of regular insulin to NPH insulin 1:1.

Long-acting insulin (insulin detemir)

Type 1 Diabetes

Initial dose

  • Type 1 diabetes: approximately one third of the total daily insulin requirements; rapid-acting or short-acting, premeal insulin should be used to satisfy the remainder of the daily insulin requirements.
  • Usual daily maintenance range is 0.5-1 unit/kg/day in divided doses; nonobese may require 0.4-0.6 unit/kg/day; obese may require 0.6-1.2 units/kg/day.

Type 2 Diabetes

  • Type 2 diabetes inadequately controlled on oral medication: 10 units/day (or 0.1-0.2 unit/kg/day).
  • Type 2 diabetes inadequately controlled on GLP-1 receptor agonist: 10 units/day.

What is the dose of insulin for a child?

Rapid-acting insulin (insulin glulisine)

  • <4 years: safety and efficacy not established.
  • 4-17 years: may require 0.8-1.2 units/kg/day during growth spurts; otherwise use adult dosing (0.5-1 unit/kg/day).

Short-acting insulin (Humulin R)

Type 1 Diabetes

  • Initial: 0.2-0.4 unit/kg/day.
  • Maintenance: 0.5-1 unit/kg/day; in insulin-resistant patients (eg, due to obesity), substantially higher daily insulin may be required.

Adolescents: may require up to 1.5 mg/kg/day during puberty.

The average total daily insulin requirement for prepubertal children varies from 0.7-1 unit/kg/day but may be much lower

Intermediate-acting insulin (Humulin N)

Type 1 Diabetes

  • <12 years: Safety and efficacy not established
  • >12 years: Suggested dose is 0.5-1 unit/kg/day; usual daily maintenance range in adolescents is ≤1.2 units/kg/day during growth spurts.

Long-acting insulin (insulin detemir)

Type 1 Diabetes

  • <2 years: Safety and efficacy not established.
  • ≥2 years: Approximately one-third of the total daily insulin requirements; rapid-acting or short-acting, premeal insulin should be used to satisfy the remainder of the daily insulin requirements; usual daily maintenance range in adolescents is ≤1.2 units/kg/day during growth spurts.

How is insulin available?

Insulin is available in the following dosage forms and strengths:

  • Syringe;
  • Injection pen;
  • Insulin pump;
  • Inhaler;
  • Injection port;
  • Jet injector.

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services (115) or go to your nearest emergency room.

What should I do if I miss a dose?

If you remember your dose before or shortly after your meal, inject the missed dose right away. If sometimes has passed since your meal, follow the instructions provided by your doctor or call your doctor to find out whether you should inject the missed dose. Do not inject a double dose to make up for a missed one.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: January 4, 2017 | Last Modified: January 4, 2017

Want to live your best life?
Get the Hello Doktor Daily newsletter for health tips, wellness updates and more.