If your doctor mentioned switching your insulin from Lantus to Basaglar — or your pharmacy told you your insurance now prefers one over the other — you're probably wondering whether anything actually changes for you day to day. The short version: not much clinically, but potentially a lot financially, and the switch isn't automatic the way a generic substitution would be.
Both Basaglar and Lantus are long-acting "basal" insulins built around the same active ingredient, insulin glargine. They were developed by different companies using different manufacturing processes, which is why regulators treat them as distinct products rather than one being a generic of the other. This guide breaks down what's actually different, what stays the same, and how to think through cost, coverage, and switching.
If you're weighing insulin costs more broadly, our insulin savings programs guide covers options beyond these two brands, including biosimilars and state-level copay caps.
Table of Contents
- Basaglar vs Lantus at a Glance
- What's the Same
- What's Different
- Cost Comparison: List Price, Insurance, and Cash Pay
- Savings Programs Compared
- Insurance and Formulary Coverage
- Medicare Part D Coverage
- Pen and Dosing Differences
- Pros and Cons of Each
- How to Switch Between Them, Step by Step
- Decision Tree: Which One Fits Your Situation
- Common Mistakes When Comparing or Switching
- Practical Examples
- Frequently Asked Questions
Basaglar vs Lantus at a Glance
| Feature | Basaglar | Lantus |
|---|---|---|
| Manufacturer | Eli Lilly | Sanofi |
| Active Ingredient | Insulin glargine | Insulin glargine |
| FDA Approval | 2015 (follow-on biologic) | 2000 (original brand) |
| Regulatory Status | Follow-on biologic (not interchangeable) | Reference brand-name biologic |
| Available Forms | KwikPen, Tempo Pen (smart pen) | SoloStar pen, multi-dose vial |
| Approved Age Range | 6 years and older | Adults and children (broader pediatric approval) |
| Typical List Price | Generally lower | Generally higher |
What's the Same
Because both medications deliver the same active molecule, the core clinical experience is very similar for most patients.
- Both are long-acting basal insulins providing roughly 24-hour coverage with one daily injection
- Both are approved for Type 1 and Type 2 diabetes
- Both are injected subcutaneously and appear as a clear, colorless solution
- Clinical studies have found comparable effectiveness and safety profiles between the two
- Common side effects — low blood sugar, injection site reactions, weight changes — are similar for both
- Dosing pens for both deliver 1–80 units per injection in 1-unit increments
What's Different
The differences that matter most to patients are regulatory status, available forms, and price — not how the drug behaves in your body.
- Basaglar cannot be automatically substituted for Lantus by a pharmacist — it requires a specific prescription
- Basaglar is not available as a vial — only prefilled pens
- Lantus has a longer track record on the market (since 2000) versus Basaglar (since 2015)
- The Basaglar Tempo Pen includes smartphone dose-tracking; Lantus pens do not have this feature
- Manufacturing processes differ slightly between facilities, which is part of why they're regulated as distinct products rather than one being a copy of the other
Cost Comparison: List Price, Insurance, and Cash Pay
List price is only the starting point — what you actually pay depends heavily on insurance, pharmacy, and whether a savings program applies. As a general pattern, Basaglar has historically launched and remained priced below Lantus.
| Price Type | Basaglar | Lantus |
|---|---|---|
| Typical list price (5-pack of pens) | Lower | Higher |
| With commercial insurance | Often preferred/lower tier | Varies by plan; sometimes non-preferred |
| With manufacturer savings program (2026) | As low as $35/month | As low as $35/month |
| Uninsured, no savings program applied | Lower than Lantus, but still costly | Higher than Basaglar, but discount cash options exist |
Important: List prices and cash prices change frequently and vary by pharmacy. Before filling either prescription, use a drug price checker to compare your specific pharmacy's cash price against your insurance copay and any manufacturer savings card, since the cheapest option isn't always obvious.
Savings Programs Compared
Both manufacturers run savings programs that can make the sticker-price gap between these two drugs mostly irrelevant for eligible patients. As of January 1, 2026, both programs cap eligible patients at $35 per month.
| Program | Sponsor | What It Covers | Monthly Cap |
|---|---|---|---|
| Lilly Insulin Value Program | Eli Lilly | All Lilly insulins, including Basaglar, for insured and uninsured patients | $35/month |
| Insulins Valyou Savings Program | Sanofi | All Sanofi insulins, including Lantus, regardless of insurance status | $35/month (expanded January 2026) |
| Lilly Cares Foundation | Eli Lilly | Free Lilly insulins for uninsured patients, generally ≤400% FPL | $0 for eligible patients |
| Sanofi Patient Connection | Sanofi | Free Lantus for eligible uninsured patients, generally ≤400% FPL | $0 for eligible patients |
Good to know: Neither of these commercial savings programs typically works with Medicare or Medicaid — those beneficiaries already benefit from the $35/month Medicare Part D insulin cap under the Inflation Reduction Act. If you're uninsured and don't qualify for the commercial savings cards, look at the manufacturer's patient assistance program directory instead.
Insurance and Formulary Coverage
Insurance plans negotiate rebates with manufacturers, and that often determines which insulin glargine product is the "preferred" option on a given formulary — this can shift year to year and plan to plan.
| Coverage Scenario | What Typically Happens |
|---|---|
| Plan prefers Basaglar | Lower copay/tier for Basaglar; Lantus may require prior authorization or cost more |
| Plan prefers Lantus | Lower copay/tier for Lantus; Basaglar may require prior authorization or cost more |
| Plan covers an interchangeable biosimilar (e.g., Semglee) | Pharmacist may substitute automatically without contacting your doctor |
| Neither is preferred | Ask your doctor about a formulary exception or check the manufacturer savings program |
If your plan requires approval before covering your preferred insulin glargine brand, our prior authorization guide explains what that process generally involves and how long it takes.
Medicare Part D Coverage
Since the Inflation Reduction Act took effect, Medicare Part D enrollees pay no more than $35 per month for each covered insulin product — including insulin glargine, regardless of whether their plan's preferred brand is Basaglar or Lantus.
- The $35 cap applies per covered insulin product, not per prescription fill size.
- Your specific Part D plan still determines which insulin glargine brand is on its formulary — check your plan's formulary or call Medicare directly to confirm which one your plan covers before assuming both are included.
- If your plan doesn't cover your preferred brand, ask your prescriber about switching to the one your plan does cover, since both are clinically similar for most patients.
For a full walkthrough of how insulin fits into Medicare drug coverage, see our Medicare Part D guide. If your income is limited, our Extra Help (LIS) guide explains how that program can lower costs further.
Pen and Dosing Differences
| Device | Brand | Format | Notable Feature |
|---|---|---|---|
| SoloStar Pen | Lantus | Prefilled, disposable | Standard prefilled pen; also available as a vial |
| KwikPen | Basaglar | Prefilled, disposable | Standard prefilled pen; pen-only, no vial option |
| Tempo Pen | Basaglar | Prefilled, disposable | Connects to a smartphone app to track insulin doses |
Each pen holds 3 mL of solution containing 300 units of insulin glargine and can deliver doses from 1 to 80 units per injection in 1-unit increments. If a single dose exceeds 80 units, more than one injection is needed — this applies to both brands equally.
Pros and Cons of Each
Basaglar
- Typically lower list price than Lantus
- Often preferred by insurance plans, meaning a lower copay for many patients
- Tempo Pen option adds smartphone dose tracking
- No vial option — pen only, which some patients find less flexible or more expensive per unit
- Shorter track record on the market compared with Lantus
- Not automatically substitutable if your prescription says "Lantus"
Lantus
- Available as both a pen and a multi-dose vial, useful for patients who prefer vial-and-syringe dosing
- Longest track record of the two, in use since 2000
- Sanofi's expanded 2026 savings program covers all Sanofi insulins at $35/month regardless of insurance status
- Typically higher list price than Basaglar
- May sit on a higher formulary tier on plans that prefer Basaglar
- No smart-pen tracking option under the Lantus brand
How to Switch Between Them, Step by Step
Check your insurance formulary first
Before asking your doctor to switch, confirm which insulin glargine brand your plan currently prefers — this often determines your actual out-of-pocket cost more than anything else.
Talk to your prescriber
Explain why you're considering a switch — cost, insurance preference, or pen features — and ask whether a new prescription for the other brand makes sense for your treatment plan.
Get a new prescription
Since Basaglar and Lantus are not interchangeable biosimilars, your doctor needs to write (or e-prescribe) a prescription specifically naming the new brand.
Confirm dosing hasn't changed
Most patients switch unit-for-unit between the two since they contain the same active ingredient, but confirm your specific dose with your prescriber rather than assuming.
Monitor blood sugar closely for the first week
Even with comparable products, individual response can vary slightly. Check your blood sugar as directed and report any unexpected highs or lows to your care team.
Apply any relevant savings program
Once your new prescription is active, register for the matching manufacturer savings card (Lilly Insulin Value Program for Basaglar, or Sanofi's Insulins Valyou Savings Program for Lantus) if you're not already enrolled.
Decision Tree: Which One Fits Your Situation
Step 1: Does your insurance plan already prefer one brand over the other?
✔ Yes → Sticking with the preferred brand usually means the lowest copay — ask your doctor about switching if you're currently on the non-preferred one.
✖ No preference / uninsured → Continue to Step 2.
Step 2: Do you need a vial-and-syringe option instead of a pen?
✔ Yes → Lantus is the only one of the two available as a vial.
✖ No, pen is fine → Continue to Step 3.
Step 3: Would you like smartphone dose tracking?
✔ Yes → Ask your doctor about the Basaglar Tempo Pen.
✖ No preference → Compare current cash and savings-card pricing for both at your pharmacy before deciding, since prices shift.
Common Mistakes When Comparing or Switching
- Assuming a pharmacist can swap Basaglar and Lantus automatically, the way generics are substituted.
- Comparing only list prices instead of your actual copay or savings-card price.
- Forgetting that Basaglar has no vial option before switching a patient who relies on vial-and-syringe dosing.
- Not re-enrolling in a manufacturer savings program after switching brands, since each program is brand-specific.
- Assuming Medicare automatically covers both brands — check your specific Part D formulary.
- Switching doses without confirming with a prescriber, even though most patients switch unit-for-unit.
The savings-card mistake is the most common one Refill Relay hears about: patients switch brands for cost reasons, but forget the old manufacturer's discount card doesn't apply to the new brand. Re-enroll in the matching program as soon as your new prescription is active.
Practical Examples
Example 1 — Insurance-preferred switch: A patient on Lantus finds out their new plan year moved Basaglar to the preferred tier. Their doctor writes a new prescription for Basaglar, dosing stays the same, and their copay drops from $60 to $25 per fill.
Example 2 — Uninsured, cash-pay: An uninsured patient compares cash prices at three pharmacies. Basaglar's list price is lower, but after applying Sanofi's Insulins Valyou Savings Program, Lantus comes out to $35/month too — so the patient stays on Lantus rather than switching prescribers.
Example 3 — Medicare beneficiary: A Medicare Part D enrollee pays $35/month for whichever insulin glargine brand their plan covers, regardless of brand, thanks to the Inflation Reduction Act cap — so brand choice comes down to their plan's formulary rather than price.
Bottom Line
Basaglar and Lantus are close enough clinically that the decision usually comes down to cost and convenience rather than effectiveness. Check your insurance formulary first, then compare cash and savings-card pricing for both before assuming one is automatically cheaper. If you do switch, it takes a new prescription — not a pharmacist substitution — so loop your doctor in early.
If cost is the main driver, look at both manufacturer $35/month programs and, if you're uninsured with limited income, the free patient assistance programs from Lilly Cares and Sanofi Patient Connection before paying full cash price.
Ready to compare your actual cost?
Use our free tool to check real-time pricing for Basaglar and Lantus at pharmacies near you before you fill your next prescription.
Compare Prices Now → See All Insulin Savings OptionsFrequently Asked Questions
Usually, yes. Basaglar's list price runs lower than Lantus's list price, and it is often the preferred insulin glargine on insurance formularies. However, cash-paying patients sometimes find Lantus discount pricing through pharmacy programs that beats Basaglar's cash price, so it's worth comparing both at your specific pharmacy.
No, not automatically. Basaglar was approved as a follow-on biologic, not an FDA-designated interchangeable biosimilar, so a pharmacist cannot substitute one for the other without a new prescription from your doctor. This is different from Semglee or Rezvoglar, which are FDA-designated interchangeable biosimilars to Lantus.
In most states, no. Because Basaglar is a follow-on biologic rather than an interchangeable biosimilar, your prescriber typically needs to write a new prescription specifically for Basaglar rather than having the pharmacy make an automatic substitution.
Both contain insulin glargine and are approved as once-daily, long-acting basal insulins with a similar 24-hour duration of action. Clinical studies have found comparable effectiveness and safety profiles between the two, though your individual response can vary.
Lantus is available in both a SoloStar prefilled pen and a multi-dose vial, while Basaglar is only available as a prefilled KwikPen or the Basaglar Tempo Pen, which connects to a smartphone app to track doses. Neither Basaglar pen option comes in a vial format.
Both are commonly covered under Medicare Part D plans, and under the Inflation Reduction Act, Medicare beneficiaries pay no more than $35 per month per covered insulin product regardless of which insulin glargine brand their plan covers. Formulary tier and specific coverage still vary by plan.
Cash prices for a box of five Basaglar KwikPens vary by pharmacy, but manufacturer savings programs can cap monthly out-of-pocket costs at $35 for eligible patients, with or without insurance, through Eli Lilly's Insulin Value Program.
Neither has a traditional generic, since both are biologic medications. However, FDA-approved biosimilars to Lantus exist, including Semglee and Rezvoglar, both designated interchangeable, meaning a pharmacist can substitute them for Lantus without a new prescription in most states.
Insurance plans periodically renegotiate manufacturer rebates, which can shift which insulin glargine brand is "preferred" from year to year. If your plan drops Lantus mid-year or at renewal, ask your doctor about switching to whichever brand — Basaglar or a biosimilar — is now preferred, or request a formulary exception.
Lantus has broader pediatric approval, while Basaglar is approved for children ages 6 and older. Your child's endocrinologist can advise on which is appropriate based on age and specific treatment needs.
Check both manufacturers' free patient assistance programs — Lilly Cares Foundation for Basaglar and Sanofi Patient Connection for Lantus — which provide free insulin to eligible uninsured patients, typically at or below 400% of the federal poverty level. NeedyMeds and BenefitsCheckUp can also help locate additional assistance programs.
How We Researched This Guide
References
- Eli Lilly and Company. Basaglar Prescribing Information and Insulin Value Program.
- Lilly Cares Foundation. Patient Assistance Program Overview.
- Sanofi. Lantus Prescribing Information and Insulins Valyou Savings Program.
- U.S. Food & Drug Administration. Biosimilar and Interchangeable Products Guidance.
- Medicare.gov. Insulin Cost-Sharing Under the Inflation Reduction Act.
- Centers for Medicare & Medicaid Services. Medicare Part D Coverage Guidance.
Related Resources
Related Insulin & Diabetes Savings Guides
- Insulin Savings Programs Compared
- Patient Assistance Programs: Full Directory
- Drug Price Checker: Compare Costs Instantly
- Manufacturer Savings Cards: How They Work
- Medicare Part D: Complete Coverage Guide
- Extra Help (LIS): Medicare Part D Low-Income Subsidy
- GoodRx vs Inside Rx: Which Saves You More?
- Express Scripts Prior Authorization Requirements
Editorial Policy: Refill Relay content is researched using publicly available manufacturer materials, federal guidance, and standard industry pricing practices. Every article is reviewed for clarity, accuracy and usefulness before publication. This content is educational and is not medical advice — always talk with your doctor or pharmacist before switching insulin products.