What is regular insulin?

Regular insulin, with alternative names soluble insulin and neutral insulin, refers to a short-acting insulin which is used with exercise and diet program to manage high blood sugar in diabetic patients. However, it can be taken in combination with other long-acting or intermediate insulin. This medication can be used alone or with other diabetes medication like metformin. Insulin regular is used to treat diabetes type 1 and diabetes type 2, in addition to gestational diabetes and other conditions such as diabetic ketoacidosis. Insulin regular refers to man made insulin that works the same as the insulin produced by the pancreas. Insulin is a hormone that works by lowering the level of blood sugar in the body. If high blood sugar is not properly managed, it can lead to severe health conditions such as heart attack and stroke.

For our bodies to properly utilize glucose found in carbohydrate rich foods, insulin is supposed to be present to facilitate the process of glucose absorption. Regular insulin works by helping glucose get into the cells so that our bodies can use to produce energy. This medication should not be used to treat type 2 diabetes in children of any age. Also, you should not use this medication if you are allergic to insulin or experience low levels of blood sugar. Hypoglycemia or low blood sugar usually happens in patients that are diabetic.

Symptoms of low blood sugar include:

  • Sweating
  • Shakiness
  • Fatigue or weakness
  • Impaired vision
  • Headache
  • Hunger
  • Loss of consciousness
  • Irritability
  • Difficulty in concentration

If you experience these symptoms and you think they are life threatening, you need to inform your doctor immediately. It is advisable you keep sugar sources such as fruit juice, non diet soda or hard candy in case you

experience low blood sugar. However, if you are experiencing severe low blood sugar and cannot eat or drink, your doctor can prescribe a glucagon injection kit and show you how to use it.

Regular insulin peak times, onset and duration of action

After injection, neutral insulin will take 30 minutes to reach your bloodstream. It usually takes 2 to 3 hours to peak and remains effective for up to 8 hours.

The onset of regular insulin is mostly 30 minutes and can last up to 8 hours.


Regular insulin is an injectable solution that is taken three or more times every day before meals. It is recommended you take insulin regular 30 minutes before your meal. For adults the average dosage requirement is between 0.5 to 1 unit/ kg every day. However, if you are starting the dosage, it is usually lower, i.e. between 0.2 to 0.4 units/ kg every day. Patients are required to inject this medicine under the skin of thigh, buttocks or back of the arm. These are part of the body where insulin gets absorbed quickly. Avoid injecting the same place twice in a row. It is important to note that you are not supposed to inject insulin soluble into a muscle or vein. In case you missed a dose, you should take it as soon as you remember. If it is time to take the next dose, you should skip the missed dose and continue with normal dosing. You should not take a double dose to make up for the missed dose. In case of an overdose, you should seek medical attention immediately. Overdose of insulin can lead to hypoglycemia, which can be life threatening.

The dosage of insulin regular is normally individualized based on factors like blood sugar levels, level of physical activity, your medical condition and other drugs you are using. To avoid side effects, you should not use smaller or larger amounts of this medication than what is prescribed by your doctor. Also, you should not change your dosage schedule without your doctor’s advice.

Side effects

Insulin regular is associated with side effects such as swelling or redness where an injection was given.

Other possible side effects include:

  • Fast heartbeats
  • Swelling of the throat or tongue
  • Difficulty breathing
  • Weight gain
  • Low blood sugar

NPH and regular insulin

NPH refers to an intermediate-acting insulin while insulin regular is a short acting insulin taken by injecting it subcutaneously. When insulin regular is taken in combination with NPH, it has a shorter onset of action compared to NPH. Insulin soluble and NPH differ in terms of duration of effects they have on the body. It takes 30 minutes to 1 hour for the medication to have effects in the body. However, NPH insulin takes 2 hours to have effects in the body. Neutral insulin has an appearance that is clear and can be taken through intramuscular injections. On the other hand, NPH has a cloudy appearance and is only taken through subcutaneous injections. Prescription that involves NPH and regular insulin is effective at reducing the level of blood sugar to a normal range.

Is regular insulin clear?

This type of insulin should have a clear appearance. You should not use this medication in case the color has changed to cloudy or has particles contained in it. In this case, you should ask for a new prescription from your doctor.

Can you mix NPH and regular insulin?

Regular insulin can be mixed with NPH and taken by patients to reduce high blood sugar in diabetic patients.

Disclaimer: Please note that the contents of this community article are strictly for informational purposes and should not be considered as medical advice. This article, and other community articles, are not written or reviewed for medical validity by Canadian Insulin or its staff. All views and opinions expressed by the contributing authors are not endorsed by Canadian Insulin. Always consult a medical professional for medical advice, diagnosis, and treatment.