Alternatives to Semglee If You Can't Fill Your Prescription

When Semglee Isn't Available, You Still Have Options

If you've been prescribed Semglee and your pharmacy can't fill it — whether due to a shortage, insurance issues, or cost — you may feel stuck. But you're not. Several other long-acting insulins work very similarly to Semglee and may be available right now.

In this post, we'll cover what Semglee is, how it works, and walk through the best alternative medications your doctor might consider. We'll also explain what to watch out for when switching insulins.

What Is Semglee?

Semglee is the brand name for Insulin Glargine-yfgn, a long-acting basal insulin manufactured by Viatris. It was the first FDA-approved interchangeable biosimilar to Lantus (Sanofi's brand-name insulin glargine).

Semglee is prescribed for:

• Type 1 diabetes in adults and children ages 6 and older
• Type 2 diabetes in adults

It's available as a pre-filled pen (100 units/mL) and a 10 mL vial. For a detailed overview, read our post on what Semglee is, its uses, and dosage.

How Does Semglee Work?

Semglee contains insulin glargine, which is a modified form of human insulin. When injected under the skin, it forms tiny clusters (microprecipitates) that dissolve slowly over approximately 24 hours. This provides a steady, "peakless" release of insulin throughout the day and night.

This basal insulin works by:

• Helping your cells absorb glucose from the bloodstream
• Reducing the amount of glucose your liver releases
• Keeping blood sugar levels stable between meals and overnight

For a deeper explanation, check out how Semglee works: mechanism of action explained.

Alternatives to Semglee

If you can't get Semglee, the following medications are the most common alternatives. All are long-acting basal insulins used for the same conditions.

1. Lantus (Insulin Glargine)

Lantus is the original brand-name insulin glargine made by Sanofi. Semglee was designed to be interchangeable with Lantus, so the two medications are essentially the same active ingredient at the same concentration (100 units/mL).

• How it's given: Subcutaneous injection, once daily
• Key difference from Semglee: Lantus is the reference (originator) product. It's been on the market since 2000.
• Cost: Lantus typically costs more than Semglee — around $250–$400 per vial without insurance. However, Sanofi has reduced list prices in recent years.
• Best for: Patients whose pharmacy has Lantus in stock and whose insurance covers it

2. Basaglar (Insulin Glargine)

Basaglar is another insulin glargine product, manufactured by Eli Lilly. It was approved as a "follow-on" biologic to Lantus (not technically labeled as an interchangeable biosimilar, but clinically very similar).

• How it's given: Subcutaneous injection via KwikPen, once daily
• Key difference from Semglee: Basaglar uses a different pen device (KwikPen). It's not officially "interchangeable" like Semglee, so your doctor needs to write a new prescription for it.
• Cost: Comparable to Semglee. Eli Lilly has capped insulin prices at $35 per month for many patients.
• Best for: Patients looking for an affordable insulin glargine option with strong insurance coverage

3. Levemir (Insulin Detemir)

Levemir is a long-acting basal insulin made by Novo Nordisk. It uses a different insulin analog — insulin detemir — rather than insulin glargine.

• How it's given: Subcutaneous injection, once or twice daily
• Key difference from Semglee: Levemir may not last a full 24 hours for all patients, which is why some people take it twice daily. It has a slightly different side effect profile and may cause less weight gain than glargine in some studies.
• Cost: Around $250–$400 per vial without insurance. Discount cards may lower the price.
• Best for: Patients who experience issues with insulin glargine or who need a twice-daily dosing option

4. Toujeo (Insulin Glargine 300 units/mL)

Toujeo is a concentrated insulin glargine product made by Sanofi. It contains 300 units/mL — three times the concentration of Semglee, Lantus, and Basaglar.

• How it's given: Subcutaneous injection via SoloStar pen, once daily
• Key difference from Semglee: The higher concentration means the insulin is absorbed more slowly and evenly. Studies show Toujeo may cause fewer episodes of low blood sugar (hypoglycemia), especially at night.
• Cost: Toujeo tends to be more expensive — around $300–$500 per pen pack without insurance.
• Best for: Patients who need higher insulin doses or who experience frequent hypoglycemia on standard glargine

Important Things to Know About Switching Insulins

Switching from Semglee to another insulin should always be done under your doctor's guidance. Here's why:

• Dose adjustments may be needed. Even when switching between insulin glargine products, your doctor may want to monitor your blood sugar closely for the first few days.
• Switching to a different insulin type (like Levemir) definitely requires medical supervision. The dosing isn't always 1:1.
• Pen devices differ. If you're switching from Semglee pens to Basaglar KwikPens or Toujeo SoloStar, make sure you understand how the new device works.
• Insurance coverage varies. Your new insulin may be on a different formulary tier, which could affect your copay. Check with your insurance before filling.

Never stop taking insulin or change your dose on your own. Always work with your healthcare provider.

Final Thoughts

Not being able to fill your Semglee prescription is stressful, but it doesn't mean you're out of options. Lantus, Basaglar, Levemir, and Toujeo are all proven alternatives that your doctor can prescribe.

Before switching, use Medfinder to check if Semglee is available at another pharmacy near you — it might save you the hassle of changing medications entirely. And if cost is a concern, read our guide on how to save money on Semglee for coupons, discount cards, and patient assistance programs.

For more on the current supply situation, check out our Semglee shortage update for 2026.