Levemir vs. Lantus – What is the Difference?

Authored by The Rx Advocates, / Medically Reviewed by Dr. Conor Sheehy, PharmD, BCPS


Levemir and Lantus are both brand-name medications. They are long-acting insulin medicines used in the treatment of diabetes. Patients who have diabetes may benefit from these medications.

Diabetes is an endocrine disorder. It occurs because the body cannot produce enough insulin on its own. When this happens, a person may be prescribed many different types of treatment. This will usually include the use of medication to control symptoms.

There are many similarities in how Levemir and Lantus work. There are also differences and interactions with other drugs.

Understanding how these medications work is essential. It is a critical aspect of the successful treatment of diabetes.

What is Levemir?

Levemir is man-made. It’s a form of the hormone insulin that’s used to regulate the body’s sugar levels. Those sugar levels are known as glucose.

Once injected under the skin, Levemir works over an extended period of time. As a long-acting insulin, it begins working within hours of injection. It then dispenses consistently over the following 20-24 hours, moderating glucose levels.

Levemir is intended for children and adults. For those with type 1 diabetes, it’s safe for ages two and older. With type 2 diabetes, Levemir is only intended for adults. It isn’t meant for sharing with others and you should only use what is prescribed to you.

Levemir Side Effects

As with any medication, Levemir can create side effects. Be aware of these potential reactions that can occur after using this drug. If you have any questions or concerns, contact your doctor or pharmacist immediately.

The most common side effects are:

  • Low blood sugar (hypoglycemia)
  • Reaction at the injection site
  • Having an allergic reaction
  • Gaining weight
  • Increased thickened skin at sites of injection (lipodystrophy)

There can be severe side effects such as low blood sugar. Talk with your doctor and pharmacist so they are able to recognize the symptoms because they can be life threatening. If hypoglycemia symptoms occur, seek emergency treatment immediately.

What is Lantus?

Created to help regulate glucose levels, Lantus is man-made insulin. Used correctly, it can manage the symptoms of diabetes.

Lantus is a subcutaneous injection. This drug can come in a vial or in a pre-filled needle pen called SoloStar.

It’s designed for people with type 1 diabetes aged six or older or adults diagnosed with type 2 diabetes.

Lantus Side Effects

Side effects for Lantus are similar to the side effects of Levemir. Direct questions or concerns about potential side effects to a doctor or pharmacist.

Some of the most common side effects include:

  • Reactions at the site of injection (such as itching, redness, or pain)
  • Low blood sugar or hypoglycemia
  • Gaining weight
  • Signs of an allergic reaction (these can include: hives, itching, swelling, or rash)

Never ignore the more severe side effects that are possible. If any of the following symptoms occur, please seek immediate medical help. Call 911 or go to a nearby hospital as soon as possible.

  • Severe allergic reaction (like swelling or difficulty breathing)
  • Severe low blood sugar
  • Severe low potassium levels

What Makes Levemir and Lantus Different?

While Levemir and Lantus are similar in many ways, there are some critical differences between the two. Recognizing those differences equals importance for knowing how they are alike. Through this awareness, patients can get everything they need to manage diabetes.

The way that these medications differ are:

  • Absorption Rate: Levemir peaks between 6-8 hours after injection, yet Lantus steadily stays at peak level for up to 24 hours.

Levemir vs. Lantus: Which Medication is More Effective?

Studies show that the effectiveness of Levemir and Lantus is evenly matched. This means that the choice of medication is a simple matter of preference or insurance coverage. It’s a decision made between the doctor and patient.

Also, follow-up blood tests and doctor evaluations will reveal necessary information. In this way, the drug most effective for each individual is shown in managing diabetes.

Medication Interactions for Levemir and Lantus

Knowing if another medicine, food, or illness will interact with Levemir and Lantus is a necessary part of treatment.

  • Medications: Unfortunately, over 300 other medicines can potentially interact with Levemir and Lantus. This can make using these drugs more challenging to balance with different medical needs. Examples of what drugs can interfere with the effectiveness of these diabetic insulins include:
    • Aspirin
    • Carvedilol (Coreg)
    • Ciprofloxacin (Cipro)
    • Doxycycline (Adoxa CK)
    • Furosemide (Lasix)
    • Hydrochlorothiazide (HCTZ)
    • Levofloxacin (Levaquin)
    • Levothyroxine (Synthroid)
    • Losartan (Cozaar)
    • Metformin (Fortamet)
    • Metoprolol (Lopressor)
    • Prednisone (Deltasone)
    • Valsartan (Diovan)
  • Illnesses: Diseases known to have interactions with Levemir and Lantus include:
    • Hypoglycemia (dangerously low blood sugar)
    • Renal or liver disease
    • Severely low potassium (hypokalemia)

The Rx Advocates Can Help You Pay for Both Levemir and Lantus

At The Rx Advocates, we understand the importance of having the necessary medication. We also understand that not everyone can cover the associated costs. Sometimes, the best medicines for the treatment are also the most expensive.

Are you one of the many taking Levemir or Lantus to treat their type 1 or type 2 diabetes? Does the cost overwhelm you? Do you find yourself choosing between monthly living expenses and taking your prescriptions?

We can help. Many people qualify for assistance through our prescription advocacy program. There is an application process that includes a review of annual income. Then, many people receive the help they need to pay for their medication.

Has your doctor prescribed either Levemir or Lantus? If you’re finding it challenging to cover the cost, The Rx Advocates may be able to help. Contact us today to see if you are eligible for assistance through our program.

  1. ADA. Diabetes. April 28, 2022. Available at: ada.com.
  2. Drugs. Lantus (insulin pen): Usage, Dosage, Side Effects. March 25, 2022. Available at: drugs.com.
  3. Drugs. Levemir: Uses, dosage, and side effects. May 2, 2022. Available at: drugs.com.
  4. Medical News Today. Levemir (insulin detemir). April 15, 2022. Available at: medicalnewstoday.com.
  5. Medical News Today. Lantus (insulin glargine). October 1, 2021. Available at: medicalnewstoday.com.
  6. Drugs. Levemir Interactions Checker. May 16, 2022. Available at: drugs.com.
  7. Drugs. Lantus and alcohol/food interactions. May 16, 2022. Available at: drugs.com.
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