Basal Insulin: Why Should I Consider It?

Insulin is a vital hormone present in everyone’s body. Its primary role is to regulate the level of sugar, or glucose, circulating in your bloodstream at any given moment.

Our livers constantly release glucose for our bodies to use for everyday activities. If the glucose level goes unchecked, it can get very high quickly. Dangerously high glucose levels can cause damage in the body and lead to strokes, eye damage, kidney damage, and nerve damage.

Basal insulin is the amount of insulin our bodies produce during periods of fasting. Basal insulin levels ensure our glucose levels stay manageable while sleeping or between meals.

People with type 1 or type 2 diabetes have an issue with insulin production or sensitivity. For this reason, they often need to inject themselves with insulin daily to regulate their glucose levels.

Basil Insulin Types

There are three types of basal insulin medications available. This includes intermediate-acting insulin, long-acting insulin, and ultra-long-acting insulin.

Intermediate-acting insulin (NPH)

Intermediate-acting insulin, NPH, is a suspension of human insulin, protamine, and zinc that delays insulin release into the bloodstream. This delay helps keep insulin levels steady and usually only needs to be injected once or twice daily for basal coverage.

Humulin N and Novolin N are the two brands of intermediate-acting insulin. They begin working between 2 to 4 hours after injection and stay in the bloodstream for 12 to 18 hours. This type of insulin has a peak concentration when it is most effective, typically around 4 hours after injection.

Humulin N and Novolin are both injectable solutions. They are both subcutaneous injections that are administered under the skin.

Long-acting insulin

Two types of long-acting insulins are available, including glargine and detemir. Glargine is sold under the brand names Lantus, Toujeo, and Basaglar. Detemir is sold under the brand name Levemir.

Glargine and detemir are basal insulin analogs that are absorbed slower and work for longer in the body. They begin working between 90 minutes to 4 hours after injection and can stay in the bloodstream for 24 hours. These medications do not have a peak concentration and remain equally effective while they are in circulation. Everyone’s body is different, so the time it takes for the medication to be broken down can vary.

Glargine and detemir cannot be mixed with rapid-acting insulins because they can alter the mediations properties by making them less effective or not last as long.

Ultra-long-acting insulin

The only ultra-long-acting insulin on the market is degludec, sold under the brand name Tresiba. This medication will begin working between 30 to 90 minutes after injection.

Degludec will remain in your bloodstream for up to 42 hours – the longest of the basal insulin medications. This medication also does not have a peak concentration, so it will maintain steady glucose concentrations as long as it is in circulation.

It can safely be mixed with rapid-acting insulins without changing the medication’s properties.


When deciding which basal insulin to choose, many factors exist, such as your personal needs, willingness to inject, and lifestyle.

Living a more active lifestyle might mean you want to select a medication that needs to be administered less frequently, such as long-acting or ultra-long-acting insulin. Choosing one of these medications means less time spent administering injections.

Another critical factor is the patient’s willingness to administer multiple injections a day. You typically want a medication schedule with the lowest number of injections possible when using insulin injections. Intermediate-acting insulin and long-acting insulin might need to be injected twice a day. Ultra-long acting is always only one injection daily, and sometimes patients can safely go longer than 24 hours between doses. Choosing a medication with only one injection a day will result in fewer needle sticks.

Additionally, long-acting insulin medications can’t be mixed with rapid-acting insulins. For this reason, you can’t administer them both simultaneously in one syringe. This is important to note if you must also administer rapid-acting insulin injections. This factor might make an ultra-long-acting insulin a better choice. Ultra-long-acting insulin can be mixed with rapid-acting insulin injections so you can administer them both simultaneously, leading to fewer needle sticks.


The exact dosage you will need depends on your metabolic needs, results of blood glucose monitoring, and glycemic control goals. Dosing should never be changed on your own and should always be discussed with your doctor.

If you have type 1 diabetes or type 2 diabetes, your exact basal insulin needs will differ. Below are the general recommendations for each type of basal insulin.

Intermediate-acting insulin (NPH) dosing

Although intermediate-acting insulin provides basal insulin requirements, it still usually has to be injected twice daily. The typical dosing schedule would be administering intermediate-acting insulin at bedtime, in the morning, or both. This schedule helps to prevent blood glucose spikes.

Humulin N comes in 100 units/mL either in a 10 mL multiple-dose vial, 3 mL multiple-dose vial, or 3 mL single-use prefilled pen. The exact dosage will need to be measured before administration. Novolin N is available as 100 units/mL in a 10 mL multiple-dose vial or a 3 mL single-use prefilled pen.

Long-acting insulin dosing

One of the major benefits of long-acting insulin is its continuous long-lasting effects. This means you will likely only need to inject long-acting insulin once daily, resulting in fewer needle sticks.

Glargine (Lantus, Toujeo, and Basaglar) is injected once a day at any time, but it must be administered at the same time each day. Detemir (Levemir) may be injected once or twice daily, depending on your specific needs.

Ultra-long-acting insulin dosing

Ultra-long-acting insulin has the most prolonged duration, so it is usually injected the least. Desgludac (Tresbia) is available in 2 concentrations: 100 units/mL and 200 units/mL. It is usually administered once daily. It is essential to discuss your exact dosing needs with your physician.

Those with type 1 diabetes already taking insulin typically start with 1/3  to 1/2 of the total daily insulin requirement once a day. Type 2 diabetics usually start with 10 units once daily. These dosages may vary based on your doctor’s recommendations.


Basal insulin has many benefits, making it an attractive medication addition for many diabetic patients.

Greater Flexibility

Basal insulin allows for flexibility and freedom in those with diabetes. Due to their longer duration of action, basal insulin makes it easier to manage blood sugar between meals and usually means patients need to give themselves fewer injections. Fewer injections mean less pain, less risk of injection side effects, and less time spent administering medications. This can all result in a more flexible and free lifestyle!

Better Glucose Control

Basal insulin can be particularly helpful in those who struggle with high glucose levels in the morning. Adding basal insulin can help prevent nighttime blood sugar elevations and keep insulin levels more steady over a 24-hour period.

Side Effects

Low Blood Sugar (Hypoglycemia)

Insulin is a powerful medication because it impacts glucose levels in our bodies. Injecting too much can lead to low blood glucose, also known as hypoglycemia. Hypoglycemia can be life-threatening if left untreated. Signs and symptoms of hypoglycemia include light-headedness, dizziness, sweating, headache, confusion, blurred vision, slurred speech, shakiness, rapid heartbeat, anxiety, irritability, mood changes, and hunger. It is important to be on the lookout for these symptoms while taking basal insulin, particularly intermediate-acting and ultra-long-acting forms, which carry a higher risk of hypoglycemia.

Allergic Reactions

Allergic reactions can occur with all medications, including basal insulin medications. An allergic reaction to basal insulin can include symptoms such as rash, hives, itching, fatigue, and heart palpitations. This is not an exhaustive list, so it is important to speak with your doctor if you experience any new symptoms when starting basal insulin injections.

Medication Interactions

Certain medications may interact with basal insulin, making it unsafe to use. Medications that are known to cause reactions include other antidiabetic agents, ACE inhibitors, corticosteroids, antipsychotics, MAO inhibitors, pentoxifylline, pramlintide, salicylates such as aspirin, octreotide, sulfonamide antibiotics, and many more. Each medication has specific interactions, so always check with your pharmacist or doctor when adding new medications to your routine, including over-the-counter medications and herbal supplements.


Basal insulin injections can be a life-changing medication addition for many people with diabetes. It can help manage blood glucose throughout the day better, leading to fewer glucose spikes and injections.

There are many options to choose from when selecting a basal insulin injection, each with its pros and cons. Ultra-long-acting insulin may sound ideal due to the low number of injections needed, but it also carries a higher risk of hypoglycemia. This is why it is important to discuss your options with a doctor knowledgeable about your medical history, current medications, and lifestyle so they can help you make the best decision.


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