More than eighty years ago, insulin was discovered, marking a significant milestone in medical history. Today, that discovery has become even more crucial as diabetes, a condition affecting blood sugar levels, ranked as the eighth leading cause of death in the US in 2021.

Managing diabetes requires a careful approach involving medication, lifestyle changes, and regular monitoring. Long-acting insulin analogs like Levemir and Lantus are vital medications for many individuals striving to control their blood sugar levels.

In this comparison, we explore the differences between Levemir and Lantus, including how they work, how effective they are, possible side effects, and factors to consider when choosing treatment. Whether you’re newly diagnosed or experienced in managing diabetes, understanding these differences can help you make better decisions about your health.

Key Differences Between Levemir and Lantus

Cost (manufacturer’s suggested retail price)$161.77 for pre-filled pens and $107.85 for a 10 ml vial$438.07 for pre-filled pens and $292.07 for a 10 ml vial
Prescription requirementPrescription-onlyPrescription-only
Active ingredientInsulin detemirInsulin glargine
BiosimilarsNot availableAvailable (Semglee and Rezvoglar)
Approved indicationsType 1 and type 2 diabetesType 1 and type 2 diabetes
FormsPrefilled pen and vialPrefilled pen and vial
Route of administrationInjectionInjection
EffectivenessHbA1c lowered by an average of 0.1% to 0.8% for type 1 diabetes and 0.6% to 2% for type 2 diabetes.HbA1c lowered by an average of 0% to 0.7% for type 1 diabetes and up to 1.7% for type 2 diabetes.
Side effectsHypoglycemia, allergic

reactions, injection site reactions, lipodystrophy, rash, and pruritus.

Hypoglycemia, allergic reactions, injection site reactions, lipodystrophy,

pruritus, rash, edema, and weight gain.

Dosage frequencyOnce or twice per dayOnce per day
Duration of actionLong-acting insulinLong-acting insulin

Efficacy and Safety

Levemir (insulin detemir) and Lantus (insulin glargine) work similarly in controlling blood sugar levels and have similar levels of efficacy. Both are effective and generally well-tolerated.

A 2017 study compared the efficacy and safety of glargine and detemir insulin in non-intensive care unit (non-ICU) hospital patients with diabetes. The results showed no significant difference in mean daily blood glucose levels, mortality rates, hospital complications, or readmission rates between the two groups.

After adjusting for potential confounding variables, there was no statistically significant difference in hypoglycemia rates. Although glargine was associated with a slightly longer hospital stay, this difference may not be clinically important.

Another study focused on the efficacy of insulin detemir versus insulin glargine, specifically for type 2 diabetes mellitus. The analysis revealed no significant differences in glycemic control, as measured by HbA1c levels, or in achieving an HbA1c of 7% or lower, with or without hypoglycemia. Rates of overall, nocturnal, or severe hypoglycemia were also similar between the two treatment groups.

However, insulin detemir was associated with less weight gain compared to insulin glargine. Additionally, patients on insulin glargine required a lower daily basal insulin dose and experienced fewer injection site reactions than those on insulin detemir. No significant differences were found in fasting plasma glucose (FPG) or 24-hour glucose profiles between the groups.

To further investigate, a 2018 systematic review and meta-analysis examined the effectiveness and safety of insulin glargine versus detemir in patients with type 1 diabetes. Out of 705 publications, 8 cohort studies were included, all classified as high quality. The analysis found no statistically significant difference in HbA1c levels between the two insulins.

While insulin detemir had some favorable outcomes, such as fewer episodes of severe hypoglycemia and lower fasting glucose levels, the overall effectiveness and safety of the two insulins were not significantly different.

Side Effects of Levemir vs. Lantus

Levemir and Lantus have similar side effects, with the most common being hypoglycemia (low blood sugar). Hypoglycemia is a significant barrier and limiting factor in managing diabetes, as it can cause unpleasant physical symptoms, potential cognitive impairment in children, and fear and anxiety over future episodes. It can also lead to serious complications, including cardiac arrhythmia, which may result in mortality.

An older study compared the risk of hypoglycemia between twice-daily insulin detemir (Levemir) and once-daily insulin glargine (Lantus) in individuals with type 1 diabetes. The study found that the overall risk was similar for both insulins. However, severe and nocturnal hypoglycemia was significantly less common with insulin detemir (Levemir).

Both medications can also cause allergic reactions and injection site reactions. A randomized, 52-week trial compared insulin detemir with insulin glargine in people with type 2 diabetes who have not yet initiated insulin treatment.

The trial found that injection site reactions were more frequent with detemir compared to glargine (4.5% versus 1.4%). Additionally, the withdrawal rate was higher in the detemir group (21% versus 13%), partly due to adverse effects like injection site reactions.

Other common side effects of Levemir and Lantus include:

  • Upper respiratory tract infections
  • Headache
  • Edema (swelling in the arms or legs)
  • Lipodystrophy (abnormal or degenerative conditions of the body’s fat tissue)
  • Rash
  • Pruritus (itching)

These side effects should be monitored by healthcare providers to manage and adjust treatment as necessary.

Weight Gain as a Side Effect

healthcare provider measuring the weight of patient, weight gain due to medication

Many ask, “Will Levemir cause weight gain?” or “Will Lantus cause weight gain?” Unfortunately, weight gain is a common side effect of insulin therapy or intensifying insulin doses. On average, insulin therapy is associated with a weight gain of 8.8-11 lbs.

So, why does Lantus or Levemir cause weight gain? This can be due to reduced glycosuria, which is the loss of glucose through urine, and overeating in response to low blood sugar. Additionally, insulin promotes the creation and storage of fat (lipogenesis) and can affect brain receptors that control appetite.

Potential weight gain can be a psychological barrier to starting insulin, and actual weight gain can affect patients’ willingness to continue treatment, leading to poor adherence and suboptimal blood sugar control. Weight gain is not just a cosmetic concern; it can also negatively impact cardiovascular health by worsening blood pressure and cholesterol levels.

Insulin detemir (Levemir) has been shown in high-quality studies to help prevent weight gain in people with both type 1 and type 2 diabetes. This weight-loss benefit is most noticeable in people with higher body fat (measured by BMI).

In a 2008 study, it was found that detemir led to slightly less weight gain compared to glargine, with reported increases of 6.6 lbs and 8.6 lbs, respectively. This was supported by a 52-week, multinational, open-label, parallel-group, noninferiority, treat-to-target trial, which reported a weight gain of 6.2 lbs with detemir versus 8.4 lbs with glargine.

The exact reasons for this weight-loss effect are not fully understood, but researchers found that insulin detemir tends to act more in the brain than in other parts of the body. This might be because it can more easily cross the barrier that protects the brain. Since insulin can reduce appetite when it acts in the brain, this might help explain why detemir helps prevent weight gain.

Active Ingredient and Mechanism of Action

Insulin detemir and insulin glargine are both long-acting insulins, but due to their unique molecular modifications, they achieve their prolonged action through different mechanisms.

Levemir (insulin detemir)

Insulin detemir is a recombinant DNA-produced human insulin analog. The key modification is attaching a 14-carbon fatty acid (myristic acid) to the B29 lysine residue. This modification increases the molecule’s affinity for binding to albumin in the bloodstream.

This means that insulin detemir is modified with a fatty acid attached. When injected, much of it binds to a protein in the blood called albumin. This binding acts like a storage, releasing the insulin slowly over time. Because it’s released slowly, it provides a steady insulin level, helping control blood sugar over a long period.

Lantus (insulin glargine) | Pharma Giant

Lantus (insulin glargine)

Insulin glargine is also a recombinant DNA-produced human insulin analog, but with different structural modifications. It has two extra arginine molecules attached to the B-chain (B31 and B32) and a substitution of glycine for asparagine at the A21 position. These modifications make glargine soluble at an acidic pH (around pH 4) but less soluble at the physiological pH (around pH 7.4).

This means that when injected, it forms tiny particles (microcrystals) because of the body’s pH level. These particles dissolve slowly, gradually releasing insulin into the bloodstream. This results in a consistent insulin level throughout the day without sharp peaks.

To summarize, insulin detemir binds to a blood protein and is released slowly, while insulin glargine forms tiny particles under the skin that dissolve over time. Both provide long-lasting insulin action.

Approved Indications

In the spring of 2001, the first long-acting insulin analog, insulin glargine, was launched in the US. Following this, insulin detemir was also introduced and is now accessible.

Both Levemir (insulin detemir) and Lantus (insulin glargine) are prescription medications that have received FDA approval for controlling high blood sugar levels in adults and children with type 1 or type 2 diabetes.

Specifically, Lantus is approved for use in children (aged 6 and above) and adults with type 1 diabetes, and adults with type 2 diabetes. In contrast, Levemir is approved for adults and children aged 2 years and older with type 1 diabetes, as well as adults with type 2 diabetes.

Dosing and Administration

Both Levemir and Lantus are administered via subcutaneous injection. However, their dosing frequencies differ, with Lantus typically given once daily and Levemir administered twice daily, based on the patient’s requirements and their healthcare provider’s guidance.

Dosage adjustments should be tailored to individual metabolic demands, regular blood glucose monitoring, glycemic management goals, diabetes type, and prior insulin therapy. Below is a summary of the dosage and administration guidelines for treating both type 1 and type 2 diabetes with Levemir and Lantus.

  • 3mL FlexPen prefilled pen
  • 10mL multi-dose vial
  • 3mL SoloStar prefilled pen
  • 10mL multi-dose vial
Strength100 units per mL100 units per mL
FrequencyOnce or twice per dayOnce per day
Dosage for type 1 diabetes (starting dose)About 1/3 of the total daily insulin requirementAbout 1/3 to 1/2 of the total daily insulin requirement
Dosage for type 2 diabetes (starting dose)0.1 to 0.2 units/kg or 10 units per day, which may be adjusted over time based on the patient’s blood sugar levels0.2 units/kg, up to 10 units per day, which may be adjusted over time based on the patient’s blood sugar levels

Source: Lantus Website and Levemir Website

For most individuals with type 1 diabetes, the typical insulin requirement ranges from 0.5 to 1 unit per kilogram (kg) of body weight per day. Patients should consult their healthcare provider for personalized guidance on determining their daily insulin needs and calculating the appropriate dosage of Lantus or Levemir. Dosage adjustments may be made over time in response to changes in blood sugar levels.


The Levemir FlexTouch pen was discontinued in February 2023. Moreover, Novo Nordisk is discontinuing Levemir FlexPens and vials in the US, effective December 31, 2024.

Switching to Other Insulin Therapies

Switching to other insulin therapies may be done for various reasons, such as achieving better glycemic control, managing side effects, or adapting to lifestyle changes.

Clinical ScenarioRecommendation
Levemir to Lantus conversionConsider converting unit-per-unit. A lower once-daily dose may be needed.
Levemir to Tresiba conversionPerform a unit-per-unit conversion of the total daily dose and administer it once daily. Alternatively, reduce the dose by 20% and administer once daily, particularly applicable for patients with type 1 diabetes (in Canada), those using twice-daily basal insulin (in Canada), or pediatric patients (in the US).

Do not increase the Tresiba dose more frequently than every 3 to 4 days.

Levemir to Toujeo conversion
  • Levemir once daily: convert unit-per-unit and give Toujeo once daily.
  • Levemir twice daily: reduce the total daily dose by 20% and give Toujeo once daily.

It may take ?5 days to see the maximum effect of the selected dose of Toujeo. Do not increase the Toujeo dose more frequently than every 3 to 4 days.

Levemir to NPH conversion
  • Convert unit-per-unit, or reduce dose by 20%.
  • Give NPH twice daily (e.g., 50:50 or 2/3 in the morning and 1/3 before dinner or bedtime).
Levemir to Basaglar conversionConsider converting unit-per-unit. A lower once-daily dose may be needed.
Lantus to Tresiba conversionPerform a unit-per-unit conversion of the total daily dose and administer it once daily. Alternatively, reduce the dose by 20% and administer once daily, particularly applicable for patients with type 1 diabetes (in Canada), those using twice-daily basal insulin (in Canada), or pediatric patients (in the US).

Do not increase the Tresiba dose more frequently than every 3 to 4 days.

Lantus to Toujeo conversionConvert unit-per-unit and give once daily. To maintain control, expect to need a higher daily dose (about 10% to 18%) of Toujeo.

It may take ?5 days to see the maximum effect of the selected dose of Toujeo. Do not increase the Toujeo dose more frequently than every 3 to 4 days.

Lantus to Basaglar conversionHas no dosing differences for insulin initiation.
Lantus to Semglee conversionInterchangeable biosimilar.
Lantus to NPH conversion
  • Convert unit-per-unit, or reduce dose by 20%.
  • Give NPH twice daily (e.g., 50:50 or 2/3 in the morning and 1/3 before dinner or bedtime).

Source: Pharmacist’s Letter

It’s essential to consult with a healthcare provider before making any adjustments to insulin therapy to ensure a smooth transition and minimize potential risks. They can provide personalized advice based on individual health status, medication history, and treatment goals.

Levemir vs. Lantus Biosimilar Availability

Another key distinction between Levemir and Lantus is the availability of biosimilars. Levemir currently lacks any available biosimilars, while Lantus has two FDA-approved interchangeable biosimilars, namely:

  • Semglee (insulin glargine-yfgn)
  • Rezvoglar (insulin glargine-aglr)

Biosimilars are biological products that are highly similar to an already approved biological medicine, known as the reference product. However, they are not identical due to the inherent complexity of biological molecules. Biosimilars are created to be comparable in terms of quality, safety, and efficacy to the reference product.

Note that biosimilars are not the same as generic versions of a medication. Biosimilars and generics offer cost-effective alternatives to brand-name drugs, but they differ in their replication process and regulatory pathways.

Generics are identical copies of small-molecule drugs produced once patent protection expires, while biosimilars are similar but not identical versions of biologics undergoing rigorous testing to ensure similarity in safety, efficacy, and quality.

Interchangeable biosimilars are a designation in the US that signifies a higher level of similarity to the reference biologic drug than standard biosimilars. To be designated as interchangeable, a biosimilar must demonstrate that it produces the same clinical result as the reference product in any given patient and that switching between the interchangeable biosimilar and the reference product does not result in any additional risks compared to using the reference product alone.

This designation allows pharmacists to substitute the interchangeable biosimilar for the reference product without needing prescriber intervention, similar to how generic drugs are substituted for brand-name drugs. It provides added assurance to healthcare providers and patients regarding the safety and efficacy of interchangeable biosimilars.

Cost of Levemir vs. Lantus

The list price of Lantus is $438.07 for pre-filled pens and $292.07 for a 10 ml vial. The retail price for a pack of 5 Lantus SoloStar pens in the US varies between $408 and $550, each SoloStar pen contains 3 mL of Lantus.

The list price for a Levemir FlexPen package of 5 prefilled pens, each containing 3 mL, is $161.77. The list price for a 10 mL vial of Levemir is $107.85. Retail prices are approximately $553.99 for the FlexPens and $127.84 for the vial.

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Duration of Action of Levemir and Lantus

Levemir and Lantus are classified as long-acting insulins, beginning to take effect within 1 to 2 hours and maintaining a steady level of action for 12 to 24 hours. Typically administered in the evening following meals, their extended duration of action minimizes the need for frequent dosing throughout the day.

Final Thoughts on Levemir vs Lantus

Levemir (insulin detemir) and Lantus (insulin glargine) are long-acting insulins prescribed for both type 1 and type 2 diabetes. While they share similarities in effectiveness and side effects, one key difference is their dosing frequency. Levemir may require two daily doses, whereas Lantus is typically injected once daily.

Additionally, Levemir may be preferred by individuals concerned about nocturnal hypoglycemia and weight gain, whereas Lantus has shown fewer injection site reactions. Both glargine and detemir offer promising options as basal insulin analogs, consulting with your healthcare provider can help determine the most suitable insulin for your needs.

Frequently Asked Questions

Which insulin is better, Levemir or Lantus?

Studies have shown similar efficacy between Levemir and Lantus in lowering blood sugar levels. However, Levemir appears to be associated with reduced weight gain and nocturnal hypoglycemia.

Can Levemir and Lantus be used together?

No. Levemir and Lantus should not be used together in a treatment regimen, but they are often prescribed alongside short or rapid-acting insulins, such as Humalog (insulin lispro), Novolog (insulin aspart), and Apidra (insulin glulisine).

How long does Lantus last?

The duration of Lantus’s effect on the body is approximately 24 hours. In essence, each dose of Lantus continues to work in the body for up to 24 hours following injection. Lantus does not act rapidly.

Does Lantus or Levemir need to be refrigerated?

Both Levemir and Lantus require refrigeration until they are opened. Once opened, both pens and vials can be stored outside of the refrigerator. It’s important to note that Levemir remains usable for up to 42 days after opening, whereas Lantus has a shorter shelf life of only 28 days once it’s been opened.

Are there any Levemir or Lantus alternatives?

Yes, there are alternatives to Levemir and Lantus available on the market. Some examples include:

  • Toujeo (insulin glargine): Toujeo is a long-acting insulin similar to Lantus but with a longer duration of action.
  • Tresiba (insulin degludec): Tresiba is a long-acting insulin that provides a consistent level of insulin action over a 24-hour period and has the flexibility to be taken at any time of day.
  • Basaglar (insulin glargine): It has the same active ingredient as Lantus.
  • Humulin N (insulin isophane): Humulin N is an intermediate-acting insulin that lasts for a shorter duration compared to Levemir and Lantus.

These alternatives may be prescribed by healthcare providers based on individual patient needs, preferences, and insurance coverage. It’s important to consult with a healthcare professional to determine the most appropriate insulin therapy for each individual.

What are the contraindications of Lantus and Levemir?

The contraindications of Lantus (insulin glargine) and Levemir (insulin detemir) include:

  • Hypersensitivity: Individuals with known hypersensitivity or allergy to insulin glargine (Lantus) or insulin detemir (Levemir) should not use these medications.
  • Hypoglycemia: Lantus and Levemir should not be used in patients with hypoglycemia (low blood sugar) or those who are experiencing an episode of hypoglycemia.
  • Diabetic ketoacidosis (DKA): Lantus and Levemir are contraindicated in patients with diabetic ketoacidosis, a serious complication of diabetes characterized by high blood sugar levels and the presence of ketones in the blood.
  • Pregnancy: While both Lantus and Levemir are generally considered safe for use during pregnancy, their use should be carefully monitored and adjusted as needed under the guidance of a healthcare provider. However, it’s important to discuss the risks and benefits with a healthcare professional before using these medications during pregnancy.
  • Breastfeeding: It is not recommended to use Lantus or Levemir while breastfeeding without consulting a healthcare provider, as insulin requirements may change during lactation.

These contraindications highlight situations where the use of Lantus or Levemir may not be appropriate or may require careful monitoring and adjustment under the supervision of a healthcare professional.

How long does it take for Lantus to work?

Lantus is classified as long-acting insulin, beginning to take effect within 1 to 2 hours.

When does Lantus or Levemir peak?

Levemir typically reaches peak concentration in the bloodstream six to eight hours after administration, with levels remaining close to peak for up to 24 hours. In contrast, Lantus does not exhibit a clear peak concentration. It absorbs into the body more gradually and consistently compared to Levemir.

How long is Lantus good for after opening?

Lantus has a short shelf life of only 28 days once opened.

Why is Levemir being discontinued?

Novo Nordisk, the manufacturer of Levemir, announced that it would gradually phase out and ultimately discontinue Levemir in the United States by December 31, 2024. The decision stems from several reasons, including global manufacturing constraints, substantial formulary losses affecting patient access starting in January 2024, and the presence of alternative treatment options in the US market.

What’s the optimal time during the day to administer Levemir?

If you’re taking Levemir once daily, the ideal time is either at bedtime or during the evening meal. If your Levemir dosage is twice daily, it’s recommended to administer it in the morning and then again 12 hours later.

Where should Levemir be injected for best results?

Administer Levemir subcutaneously (beneath the skin) at any of the following injection sites: the thigh, upper arm, or abdomen. Always use a fresh needle for each injection.

What contributes to the high cost of Levemir?

Insulin, including Levemir, is expensive. Insulin falls under the category of biologics, intricate molecules derived from living cells. Certain insulin variants are deemed “preferred” and incur lower costs on your healthcare plan. Your healthcare provider can assess whether there’s a suitable alternative available for you.


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