Yes, there are several lower-cost alternatives to Lantus available in the United States. Three insulin glargine products can be used in place of Lantus: Semglee, Rezvoglar, and Basaglar. All contain the same active ingredient and work the same way, though they differ in how easily your pharmacist can swap them in.
Your Three Options
Insulin is a biologic medication, which means it’s made from living cells rather than synthesized chemically like most pills. Because of that distinction, alternatives to Lantus aren’t called “generics” in the traditional sense. They’re called biosimilars. The practical difference for you is small: biosimilars go through rigorous testing to confirm they work just as well as the original, and clinical trials consistently show no meaningful difference in blood sugar control or safety between these products and Lantus.
Semglee (insulin glargine-yfgn) was approved by the FDA in July 2021 and was the first insulin product of any kind to receive an “interchangeable” designation. It’s available as both a 10 mL vial and a 3 mL prefilled pen.
Rezvoglar (insulin glargine-aglr) received its interchangeable designation in November 2022. Like Semglee, it can legally be swapped in at the pharmacy counter.
Basaglar was approved under older regulatory rules before insulin was classified as a biologic. It’s sometimes called a “follow-on” insulin rather than a true biosimilar. This matters because Basaglar cannot be substituted at the pharmacy the way Semglee and Rezvoglar can. Your prescriber must write for Basaglar by name.
What “Interchangeable” Means for You
The interchangeable label is the key detail that affects your experience at the pharmacy. When a biosimilar is designated interchangeable, your pharmacist can substitute it for Lantus without calling your doctor first, much like a pharmacist would swap a brand-name pill for a generic. Semglee and Rezvoglar both carry this designation.
There’s one caveat: substitution rules are set at the state level. Most states allow pharmacists to make the switch, but some require the pharmacist to notify your prescriber after the fact, and a handful have additional restrictions. If your pharmacist says they can’t make the swap, state law is likely the reason. In that case, ask your doctor to write a new prescription specifying the biosimilar by name.
How Biosimilars Compare to Lantus
Clinical trials have found no clinically meaningful differences between Lantus and its biosimilars. In a phase 3 trial of 576 people with type 1 diabetes, the difference in A1C reduction between a biosimilar glargine and Lantus after 26 weeks was just 0.08 percentage points, well within the range considered equivalent. Safety profiles and immune responses were also comparable.
Real-world data backs this up. A study tracking patients who switched from Lantus to Basaglar found no statistically significant change in A1C levels after the switch (mean difference of 0.18, which was not statistically significant). A larger study of 225 adults confirmed the same finding over 12 months of follow-up. In short, you should not expect any change in how well your blood sugar is controlled.
Switching Is Straightforward
When moving from Lantus to any of its biosimilars, the conversion is typically one-to-one. If you take 30 units of Lantus at bedtime, you’ll take 30 units of the biosimilar at bedtime. Your doctor may still want to monitor your blood sugar a bit more closely in the first few weeks, but dose adjustments are rarely needed based on the clinical evidence.
The pens and vials may look and feel slightly different from what you’re used to. The injection technique and storage requirements are essentially the same. Check the packaging for any differences in how the pen mechanism works so you’re comfortable before your first dose.
Cost Considerations
Biosimilars generally carry a lower list price than the brand-name product, but what you actually pay depends on your insurance plan and pharmacy. If you have commercial insurance, the copay difference between Lantus and a biosimilar can range from modest to substantial. For people without insurance, biosimilars are often meaningfully cheaper.
It’s also worth knowing that Sanofi, the maker of Lantus, offers a savings program that caps out-of-pocket costs at $35 per 30-day supply for commercially insured patients. Starting January 1, 2026, that $35 cap will expand to all Americans regardless of insurance status, including those on Medicare and those without coverage. Depending on your situation, this program could make Lantus itself competitive with biosimilar pricing. Compare both options before assuming the biosimilar is automatically cheaper for you.
If cost is the primary reason you’re looking for an alternative, call your pharmacy and ask for the cash price of each option, or use a price comparison tool. The cheapest choice varies by pharmacy and by whether you use a vial or pen.