| Active Ingredient | Insulin glargine 100 units/mL |
| Duration of Action | ~24 hours |
| Lantus Pen Max Dose | 80 units/injection |
| Basaglar Pen Max Dose | 60 units/injection |
| Vial Option | Lantus only |
| FDA Interchangeable? | No β prescriber approval required |
| Typical Price Difference | Basaglar ~15β20% cheaper |
Key Takeaways
- Lantus and Basaglar both contain insulin glargine 100 units/mL β the same active ingredient.
- Basaglar is a biosimilar (follow-on biologic) to Lantus, typically 15β20% cheaper.
- They use different delivery devices and are not automatically interchangeable without prescriber approval.
- Both provide ~24-hour basal coverage with a relatively flat action profile.
What Are Lantus and Basaglar?
Lantus (insulin glargine, Sanofi) was FDA-approved in 2000 and became the world's best-selling insulin. Basaglar (insulin glargine, Eli Lilly/Boehringer Ingelheim) was approved in 2015 as the first biosimilar basal insulin in the United States. Both deliver 100 units/mL of insulin glargine and work by providing steady, long-acting background insulin for people with Type 1 or Type 2 diabetes.
Side-by-Side Comparison
| Feature | Lantus | Basaglar |
|---|---|---|
| Active ingredient | Insulin glargine U-100 | Insulin glargine U-100 |
| Manufacturer | Sanofi | Eli Lilly |
| FDA approval | 2000 | 2015 |
| Pen device | SoloSTAR pen | KwikPen |
| Vial available | Yes | No |
| Typical list price | ~$300/vial | ~$250/vial |
| Duration of action | ~24 hours | ~24 hours |
| Peak action | Relatively flat | Relatively flat |
Are They Interchangeable?
Despite having the same active molecule, the FDA classifies Basaglar as a biosimilar, not an interchangeable biosimilar. This means pharmacists cannot automatically substitute one for the other without explicit prescriber authorization β unlike generic small-molecule drugs. Always confirm with your doctor before switching. Clinical studies have shown comparable glycemic outcomes between the two products.
Cost and Insurance Coverage
Cost is often the deciding factor. Basaglar's list price runs approximately 15β20% lower than Lantus. However, your actual out-of-pocket cost depends on insurance formulary placement. Some plans now prefer Basaglar and charge higher copays for Lantus. Sanofi's Insulins Valyou Savings Program and Lilly's Insulin Value Program can reduce costs significantly for eligible patients.
Device Differences
Lantus uses the SoloSTAR pen (3 mL cartridge, max 80 units/injection) while Basaglar uses the KwikPen (3 mL cartridge, max 60 units/injection). Lantus is also available in 10 mL vials β useful for syringe users or high-dose patients β while Basaglar is pen-only. Patients requiring more than 60 units per injection must use Lantus or split their Basaglar dose.
Which Should You Choose?
For most patients, clinical effectiveness is equivalent. The best choice depends on: insurance coverage (check your formulary), dose requirements (Lantus if >60 units/injection), device preference (pen ergonomics differ), and cost (Basaglar is generally cheaper). MDS Diabetes offers a range of compatible pen needles and blood glucose monitors to support your basal insulin routine β visit mdsdiabetes.com for supplies compatible with both SoloSTAR and KwikPen devices.
Important Safety Notes
- Never mix either insulin with other insulins in the same syringe.
- Both should be injected subcutaneously β never IV.
- Rotate injection sites to prevent lipodystrophy.
- Store unopened pens/vials in the refrigerator (36β46Β°F); in-use pens can be kept at room temperature for 28 days.