Lantus vs. Basaglar: Are They Really the Same Insulins? Here Are 6 Ways They Compare

Lantus (insulin glargine) is a popular long-acting insulin that has been around for over 20 years. 

But for many people, the price of insulin sometimes makes it difficult to access. Fortunately, there are now programs in place that help make insulins such as Lantus more affordable. And there are several Lantus alternatives to consider, too.

The first Lantus alternative on the market was Basaglar (insulin glargine). In 2015, it became the first follow-on insulin to Lantus. Follow-on insulins are “copies” of insulins that are already FDA approved. They’re sometimes less expensive, providing lower-cost options. However, as with Lantus and Basaglar, they’re not identical to the original medication. Here are six ways Lantas and Basaglar compare.

1. Lantus and Basaglar both contain insulin glargine

Insulin glargine is the active ingredient in both Lantus and Basaglar. It’s a long-acting insulin that takes about 1.5 to 2 hours to start working, but it provides steady amounts of insulin for about 24 hours.

This is in contrast to rapid- and short-acting insulins that you may inject at mealtimes to prevent blood glucose (sugar) spikes after you eat. These insulins kick in fast but last a shorter amount of time. You may be prescribed a faster-acting insulin with a long-acting insulin.

2. Lantus and Basaglar are made differently

Basaglar has the same chemical structure as Lantus. But the two insulins are made differently, which means there may be slight variations between the products.

It’s common for manufacturers to make generics by copying the formulations of brand-name medications when their patents expire. But insulin is a biologic, meaning it’s a medication derived from living organisms. Biologics are more complicated to make than traditional medications, such as oral pills made from chemicals. So manufacturers aren’t able to copy them in the same way they would for traditional generics.

So, even with the same active ingredient, Basaglar isn’t technically a generic equivalent of Lantus. In fact, Lantus doesn’t have a generic equivalent; it has biosimilars, or insulins that have been shown to be highly similar and deliver clinically equivalent results.

Basaglar was on the market before biosimilar approval was established for insulins. So it’s not technically classified as a biosimilar, even though the two are very similar. Currently, there are two FDA-approved Lantus biosimilars: Semglee (insulin glargine-yfgn) and Rezvoglar (insulin glargine-aglr), which are interchangeable with Lantus.

3. Lantus and Basaglar are similarly effective at lowering blood glucose

Lantus and Basaglar both provide consistent blood glucose-lowering effects for about 24 hours. They’ve been shown to be similarly effective and have comparable side effects.

However, studies haven’t tested whether you can switch back and forth between Lantus and Basaglar without issues. For this reason, they aren’t considered interchangeable. 

4. Lantus and Basaglar are administered the same way, but are available in different dosage forms

Both Lantus and Basaglar are injected under the skin (subcutaneous) in the upper arm, stomach, or thigh. You’ll usually inject a dose once daily, at the same time each day. The amount you inject will depend on your individual needs. But the dose is typically the same whether you’re injecting Lantus or Basaglar.

One difference between Lantus and Basaglar is their dosage forms. Lantus is available in a vial and a SoloStar injection pen. Basaglar comes in two different injection pens: a KwikPen and Tempo Pen. The two Basaglar pens are similar, but the Tempo Pen can connect to your smartphone to track your doses.

5. Lantus and Basaglar can cause similar side effects

Whether you’ve been prescribed Lantus or Basaglar, you can expect similar side effects. The most common is hypoglycemia, or low blood glucose levels. This can cause symptoms such as sweating, shaking, and a fast heartbeat. Other possible Lantus and Basaglar side effects include:

• Injection site reactions

• Hardening of the skin around the injection site

• Headache

• Upper respiratory tract infection

• Weight gain

• Low potassium levels

• Allergic reactions

6. Lantus and Basaglar can interact with similar medications

Several medications can interact with insulins such as Lantus and Basaglar, making them less effective or causing them to lower blood glucose more than expected.

Examples of medications that increase the risk of hypoglycemia with Lantus and Basaglar include:

• Insulin-releasing medications, such as sulfonylureas and meglitinides

• Glucagon-like peptide-1 agonists, such as semaglutide (Rybelsus, Ozempic, Wegovy)

• Fluoroquinolone antibiotics, such as ciprofloxacin (Cipro)

Examples of medications that can increase blood glucose levels include:

• Corticosteroids, such as prednisone

• Thiazide diuretics, such as hydrochlorothiazide (Microzide)

• Beta blockers, such as atenolol (Tenormin)

Be sure to provide your current medication list to your healthcare team. That way, they can check for potential interactions and manage them in advance.

Who shouldn’t take Lantus or Basaglar?

You shouldn’t take Lantus or Basaglar if you’re allergic to any of their ingredients. If you are allergic to one of the ingredients (active or inactive), you may need to take a different insulin. If you have Type 2 diabetes, an oral diabetes medication or a non-insulin injectable medication may be a potential alternative.

Can Lantus be substituted for Basaglar (or vice versa)?

As mentioned above, Basaglar is not a generic equivalent of Lantus. It’s also not considered interchangeable with Lantus. If you’re prescribed Lantus and would like to switch to Basaglar, your prescriber will need to write you a new prescription. Your pharmacist cannot automatically substitute one for the other without their approval.

However, Lantus is interchangeable with Semglee and Rezvoglar. That’s because studies have shown that you can switch between products without issues. This means your pharmacist may be able to substitute Semglee or Rezvoglar for your Lantus prescription (depending on your state’s laws).

How to save on Lantus and Basaglar

There are ways to save on Lantus and Basaglar. GoodRx can help you navigate the ways to save on your insulin prescription.

How to save on Lantus

There are ways to save on Lantus, which is available as a reference biologic. GoodRx can help you navigate between GoodRx coupons, copay savings cards, and patient assistance programs to save money on your prescription.

• Save with GoodRx: Anyone with a valid prescription, regardless of insurance status, can use GoodRx to purchase a 30-day supply of Lantus at an exclusive cash price of $35.

• Save with a copay savings card: If you have commercial insurance, you may be eligible to pay as little as $35 per month for Lantus using a savings card from the manufacturer.

• Save with patient assistance programs: If you’re uninsured or underinsured, you may be eligible for Lantus’ patient assistance program, which offers the medication free of charge.

• Save with a biosimilar. Depending on your location, your pharmacist may be able to switch you to a Lantus biosimilar. Semglee (insulin glargine-yfgn) and Rezvoglar (insulin glargine-aglr) are two biosimilars that are considered interchangeable with Lantus.

How to save on Basaglar

There are also ways to save on Basaglar:

• Save with GoodRx: With GoodRx discounts, Basaglar’s price is as low as $261.53.

• Save with a copay savings card: If you’re eligible, you could pay as little as $35 per month for Basaglar using a savings card from the manufacturer.

• Save with patient assistance programs: If you’re uninsured or underinsured, you may be eligible for the patient assistance program Basaglar, which offer the medications free of cost.

Why trust our experts?

Written by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Our editorial standards

Meet our experts