Lantus Is a Long-Acting Insulin Used to Manage Type 1 and Type 2 Diabetes

Lantus (Insulin Glargine) is a long-acting basal insulin that provides steady blood sugar control for approximately 24 hours with a single daily injection. If you've been prescribed Lantus — or your doctor has mentioned it — this guide covers everything you need to know: what it is, how it's used, dosing basics, who shouldn't take it, and what it costs in 2026.

What Is Lantus?

Here are the key facts:

• Brand name: Lantus, Lantus SoloStar
• Generic name: Insulin Glargine
• Drug class: Long-acting basal insulin analog
• Manufacturer: Sanofi
• FDA approval: Originally approved by the FDA in 2000
• Controlled substance: No — Lantus is not a controlled substance

Lantus is a recombinant human insulin analog, meaning it's made in a lab to mimic the insulin your body naturally produces, but with modifications that give it a much longer duration of action. Unlike rapid-acting insulins that cover meals, Lantus provides a baseline level of insulin throughout the day and night — which is why it's called a "basal" insulin.

For a deeper explanation of how it works in your body, see our guide: How Does Lantus Work? Mechanism of Action Explained.

What Is Lantus Used For?

Lantus is FDA-approved to improve blood sugar control in:

• Adults and children (6 years and older) with type 1 diabetes mellitus — In type 1 diabetes, the body doesn't produce insulin. Lantus provides the baseline insulin these patients need, typically alongside a rapid-acting insulin for meals.
• Adults with type 2 diabetes mellitus — In type 2 diabetes, the body doesn't use insulin effectively. When oral medications and lifestyle changes aren't enough, Lantus helps maintain steady blood sugar levels throughout the day.

Lantus is also used off-label for gestational diabetes (diabetes during pregnancy) when lifestyle changes alone don't control blood sugar. It's considered a first-line insulin option for this use.

How Is Lantus Taken?

Lantus is injected subcutaneously (under the skin) once daily, at the same time each day. Here's what you need to know about taking it:

Available Forms

• 10 mL vial (100 Units/mL) — Used with insulin syringes
• 3 mL SoloStar prefilled pen (100 Units/mL, box of 5 pens) — Convenient, pre-filled, and doesn't require a separate syringe

Dosing

Your doctor will determine the right dose for you based on your diabetes type, blood sugar levels, weight, and other medications. Some general guidelines:

• Type 2 diabetes starting dose: Typically 0.2 units per kilogram of body weight per day, or about 10 units once daily
• Type 1 diabetes: Lantus usually covers about 40–50% of total daily insulin, with the rest covered by rapid-acting insulin at meals
• Dose range: Varies widely — from 10 to 80+ units per day depending on individual needs
• Adjustments: Your doctor will adjust your dose gradually based on blood sugar monitoring

Important Instructions

• Inject into the fatty tissue of your abdomen, thighs, upper arms, or buttocks
• Rotate injection sites with every injection to prevent lipodystrophy
• Do NOT inject Lantus intravenously (into a vein)
• Do NOT use Lantus in an insulin pump
• Do NOT mix Lantus with any other insulin in the same syringe
• Do NOT use if the solution is cloudy or contains particles

Storage

• Unopened: Refrigerate at 36°F–46°F (2°C–8°C). Do not freeze.
• Opened (in use): Store at room temperature (up to 86°F/30°C) for up to 28 days. Discard after 28 days.

Who Should Not Take Lantus?

Lantus is not right for everyone. You should not use it if you:

• Are allergic to Insulin Glargine or any of the ingredients in Lantus
• Are currently experiencing hypoglycemia (low blood sugar) — treat the low first

Tell your doctor before starting Lantus if you:

• Have kidney or liver disease (may need lower doses since insulin clears more slowly)
• Are pregnant, planning to become pregnant, or breastfeeding
• Take thiazolidinediones like Pioglitazone or Rosiglitazone (increased risk of heart failure when combined with insulin)
• Take any medications that affect blood sugar — see our Lantus drug interactions guide

For a complete overview of side effects, read: Lantus Side Effects: What to Expect and When to Call Your Doctor.

How Much Does Lantus Cost?

Here's what you can expect to pay in 2026:

• Without insurance: $80–$360 per vial or box of pens (after Sanofi's 78% list price reduction in 2024)
• With GoodRx coupons: As low as $35–$100
• Sanofi Valyou Savings Program: No more than $35 per 30-day supply for eligible insured and uninsured patients
• Medicare Part D: Capped at $35/month under the Inflation Reduction Act
• Generic/biosimilar Insulin Glargine: $35–$150 per vial or box of pens with coupons

If cost is a barrier, Sanofi's Patient Connection program provides free Lantus to eligible uninsured or underinsured patients who meet income requirements. For a full breakdown of savings options, see: How to Save Money on Lantus.

You may also want to ask your doctor about alternatives to Lantus like Basaglar, Semglee, Toujeo, or Tresiba, which may be more affordable depending on your insurance plan.

Final Thoughts

Lantus has been a cornerstone of diabetes management for over two decades. It's effective, well-studied, and available in convenient forms that make once-daily dosing straightforward. Whether you're newly prescribed or refilling a long-standing prescription, knowing how to take it correctly, what side effects to watch for, and how to save money puts you in control of your care.

Need help finding Lantus at a pharmacy near you? Medfinder can show you which pharmacies have it in stock — no phone calls required.