Semglee (Insulin Glargine)

What Is Semglee and What Is It Used For?

Semglee (insulin glargine) is a long-acting basal insulin analog used to control blood sugar in people with type 1 and type 2 diabetes mellitus. It is injected subcutaneously once daily and provides a relatively flat, peakless insulin action for approximately 24 hours, helping regulate glucose levels between meals and overnight.

Semglee is a pre-filled disposable insulin pen containing insulin glargine, a long-acting human insulin analog produced by recombinant DNA technology in non-pathogenic laboratory strains of Escherichia coli. It belongs to the pharmacological class of long-acting basal insulins and is widely used worldwide for the management of diabetes mellitus. The product is manufactured by Biocon Biologics in partnership with Viatris (formerly Mylan), and is approved as a biosimilar to the reference insulin glargine product Lantus.

The prolonged action of insulin glargine is achieved through a unique mechanism. The molecule has been modified from human insulin by substituting the asparagine at position A21 with glycine and adding two arginine residues to the C-terminus of the B chain. These changes shift the isoelectric point of the insulin molecule closer to a neutral pH. The product is formulated as a clear, acidic solution (pH approximately 4.0), but once injected into the subcutaneous tissue – which has a neutral pH – insulin glargine forms microprecipitates from which small amounts of insulin are slowly and steadily released into the bloodstream over approximately 24 hours.

Semglee is indicated for the treatment of diabetes mellitus in adults and in children aged 6 years and older (with type 1 diabetes). In type 1 diabetes, Semglee is used as the basal component of a basal-bolus insulin regimen, alongside rapid-acting mealtime insulin such as insulin aspart, insulin lispro, or insulin glulisine. In type 2 diabetes, it may be used alone or in combination with oral antidiabetic medicines (such as metformin, sulfonylureas, DPP-4 inhibitors, or SGLT2 inhibitors) and/or GLP-1 receptor agonists, depending on the patient's individual needs and glycemic control.

What is a biosimilar, and why does it matter?

A biosimilar is a biological medicine that is highly similar to an already-approved reference biological medicine (the "originator"). Unlike generic versions of small-molecule drugs, which are chemically identical to their originators, biologics are large, complex proteins that cannot be exactly duplicated. Biosimilars must demonstrate that they have no clinically meaningful differences from the reference product in terms of safety, purity, and potency.

Semglee was developed as a biosimilar of Lantus (insulin glargine), the reference product originally developed by Sanofi. In July 2021, the U.S. Food and Drug Administration (FDA) designated Semglee as the first interchangeable biosimilar insulin, meaning that a pharmacist may substitute Semglee for Lantus at the pharmacy counter without requiring a new prescription (subject to state law). This represents an important milestone in expanding access to affordable insulin therapy.

Extensive analytical, preclinical, and clinical comparability studies have demonstrated that Semglee matches Lantus in structural characteristics, pharmacokinetics, pharmacodynamics, immunogenicity, efficacy (HbA1c reduction), and safety profile (including rates of hypoglycemia). Clinical switching studies have shown that patients can alternate between Semglee and Lantus without any change in clinical outcomes.

Pharmacokinetics at a glance

After subcutaneous injection, Semglee has an onset of action of approximately 3–4 hours. Its pharmacodynamic profile is characterized by a relatively flat, peakless curve, which distinguishes it from older intermediate-acting insulins such as NPH (isophane) insulin that have pronounced peaks and greater variability. The total duration of action is approximately 24 hours, making Semglee suitable for once-daily dosing in most patients. Steady-state concentrations are generally achieved after 2–4 days of consistent daily dosing.

Insulin glargine is metabolized in the subcutaneous tissue to two active metabolites (M1 and M2), which retain insulin activity and are largely responsible for the drug's clinical effect. Metabolism and elimination follow pathways similar to native insulin, primarily via insulin-degrading enzymes in the liver and kidneys. There are no significant differences in pharmacokinetics between older and younger adults, although patients with severe renal or hepatic impairment may have reduced insulin requirements due to slower clearance.

What Should You Know Before Taking Semglee?

Before starting Semglee, inform your healthcare provider about all medical conditions, current medications, allergies, and whether you are pregnant or breastfeeding. Semglee must not be used during episodes of hypoglycemia or if you are allergic to insulin glargine or any of its excipients.

Your healthcare provider will review several factors before prescribing Semglee, including the type of diabetes, current glycemic control (HbA1c), kidney and liver function, concomitant medications, risk of hypoglycemia, lifestyle factors, and prior insulin use. Understanding the contraindications, warnings, and precautions below will help you use Semglee safely and effectively and recognize situations that require additional monitoring or medical attention.

Contraindications

Semglee must not be used in the following situations:

• Hypersensitivity: Do not use Semglee if you are allergic to insulin glargine or to any of the other ingredients (zinc, metacresol, glycerol, sodium hydroxide, hydrochloric acid, polysorbate 20, and water for injections). Signs of allergy include rash, hives, itching, swelling, and difficulty breathing
• Hypoglycemia: Never inject Semglee when you are experiencing an episode of low blood sugar. Treat the hypoglycemia first (with fast-acting glucose) before resuming your normal insulin schedule
• Diabetic ketoacidosis (DKA): Semglee is not the appropriate treatment for DKA or hyperosmolar hyperglycemic state, which require intravenous regular insulin in a hospital setting

Warnings and Precautions

Several clinical situations require special attention and closer monitoring when using Semglee:

• Switching between insulins: Transitions from another basal insulin to Semglee (or vice versa) should be supervised by your healthcare provider. Switching from NPH insulin twice daily to once-daily Semglee typically requires a 20–30% dose reduction in the first weeks; when switching between Semglee and Lantus, no dose change is usually needed because they contain the same active ingredient at the same concentration
• Illness and stress: Infections, fever, surgery, trauma, and emotional stress increase insulin requirements. Temporary dose increases and more frequent blood glucose monitoring may be necessary during these periods
• Renal and hepatic impairment: Reduced kidney or liver function can decrease insulin clearance, potentially requiring dose reductions. Patients with advanced kidney disease should be monitored especially carefully for hypoglycemia
• Thiazolidinedione combination: Concomitant use of thiazolidinediones (pioglitazone) with insulin may increase the risk of fluid retention and congestive heart failure, particularly in patients with pre-existing cardiac risk factors. Report any swelling, rapid weight gain, or breathlessness to your doctor
• Hypokalemia: All insulins can cause a shift of potassium from the blood into cells, potentially resulting in low serum potassium. This is especially relevant in patients taking potassium-lowering medications (such as loop diuretics) or those with pre-existing hypokalemia
• Injection site reactions: Rotate injection sites within the same body region to reduce the risk of lipohypertrophy (lumps of fatty tissue), which can alter insulin absorption and make blood glucose control unpredictable
• Never share pens: Do not share your Semglee pen with another person, even if the needle is changed. Pen sharing carries a serious risk of transmitting blood-borne pathogens such as hepatitis B, hepatitis C, and HIV
• Accidental mix-ups: Always check the label before each injection. Confusing basal (long-acting) insulin with rapid-acting or intermediate-acting insulin can cause severe hypoglycemia or hyperglycemia

Pregnancy and Breastfeeding

Semglee (insulin glargine) can be used during pregnancy when clinically indicated. Large observational studies and meta-analyses of pregnancies exposed to insulin glargine have not shown an increased risk of adverse maternal or fetal outcomes compared with NPH insulin or other insulin analogs. Adequate glycemic control during pregnancy is essential for both mother and baby, as uncontrolled diabetes is associated with congenital malformations, macrosomia, neonatal hypoglycemia, and other complications.

Insulin requirements change substantially during pregnancy. They typically decrease in the first trimester (sometimes leading to hypoglycemia), then increase progressively during the second and third trimesters as insulin resistance rises. After delivery, insulin requirements usually return rapidly (within 24–48 hours) to or below pre-pregnancy levels, which increases the risk of postpartum hypoglycemia. Close collaboration with an obstetric and diabetes care team is essential.

During breastfeeding, insulin treatment poses no risk to the infant. Insulin is a large protein that would be broken down in the infant's gastrointestinal tract even if it passed into breast milk. However, breastfeeding mothers may need to adjust their insulin dose and food intake, as lactation can increase the risk of hypoglycemia. Continue routine blood glucose monitoring and consult your healthcare provider for personalized advice.

Driving and operating machinery

Hypoglycemia can impair concentration, reaction time, and judgment, all of which are critical for safe driving. If you experience symptoms of low blood sugar, do not drive or operate heavy machinery until the hypoglycemia is fully resolved and your cognitive function has returned to normal. Patients with hypoglycemia unawareness (reduced or absent warning symptoms) should take particular care and may need to reconsider driving. Some countries have specific regulations for drivers with diabetes – consult your healthcare provider or licensing authority for guidance.

How Does Semglee Interact with Other Drugs?

Many medicines can affect blood glucose levels and may require Semglee dose adjustments. Drugs that enhance glucose lowering (e.g., sulfonylureas, GLP-1 agonists, SGLT2 inhibitors) increase the risk of hypoglycemia, while drugs that raise blood glucose (e.g., corticosteroids, atypical antipsychotics) may reduce Semglee's effectiveness and require dose increases.

Drug interactions with insulin can be clinically significant because they may alter blood glucose levels, causing either dangerous hypoglycemia or loss of glycemic control. Always inform your healthcare provider and pharmacist about all medicines you take – including prescription drugs, over-the-counter medications, vitamins, herbal products, and supplements. The tables below summarize the most clinically important interactions.

Major Interactions – Increased Risk of Hypoglycemia

The following medicines may enhance the blood-sugar-lowering effect of Semglee, meaning your insulin dose may need to be reduced to avoid hypoglycemia:

Minor Interactions – Reduced Insulin Effect (Hyperglycemia Risk)

The following medicines may reduce the blood-sugar-lowering effect of Semglee, potentially requiring an insulin dose increase:

What Is the Correct Dosage of Semglee?

Semglee dosing is highly individualized and determined by your healthcare provider based on your blood glucose readings, HbA1c, weight, and insulin sensitivity. It is typically given once daily at the same time each day by subcutaneous injection. Common starting doses are 10 units or 0.2 units/kg once daily in type 2 diabetes, and approximately one-third to one-half of total daily insulin in type 1 diabetes.

There is no universal dose of Semglee – insulin therapy must be individualized. Your healthcare provider will determine an appropriate starting dose and adjust it gradually (titrate) over days to weeks based on your self-monitored blood glucose readings, HbA1c targets, and overall response. The dosing information below is a general guide based on international clinical practice guidelines (ADA, EASD, NICE) and should not replace personalized medical advice.

Adults – Type 2 Diabetes

Adults – Type 1 Diabetes

Children (aged 6 years and older with type 1 diabetes)

Elderly

Switching between insulins

Missed Dose

If you miss a dose of Semglee, take it as soon as you remember, provided it is reasonably close to your usual dosing time. Do not take a double dose to make up for a missed one. If you are within a few hours of your next scheduled dose, skip the missed dose and continue with your regular schedule. Missing a dose will typically result in elevated blood glucose the following day; check your blood sugar and, if very high, contact your healthcare provider for advice.

To avoid missed doses, try to inject Semglee at the same time every day. Setting a daily phone alarm or linking the injection to a daily routine activity (such as brushing your teeth before bed, or with morning coffee) can help build a consistent habit.

Overdose

An insulin overdose – whether from injecting too many units, injecting the wrong type of insulin, or an unplanned reduction in food intake – can cause hypoglycemia, which can range from mild to severe. Severe hypoglycemia can include loss of consciousness, seizures, and, if untreated, permanent neurological damage or death.

• Mild to moderate hypoglycemia: Consume 15–20 grams of fast-acting carbohydrates (for example, 3–4 glucose tablets, half a cup of fruit juice or regular soda, or one tablespoon of sugar or honey). Recheck blood glucose after 15 minutes. If still low, repeat. Once blood glucose has normalized, eat a longer-acting snack (such as a sandwich or fruit) to prevent recurrence
• Severe hypoglycemia: If the person is unconscious, confused, or unable to swallow safely, do not give food or drink by mouth. Administer intramuscular glucagon (if available and trained) or a nasal glucagon spray. Call emergency services immediately. Place the person on their side (recovery position) to prevent choking on saliva or vomit

How Do You Use the Semglee Pen?

Semglee is injected subcutaneously (under the skin) into the abdomen, thigh, or upper arm. Always use a new needle for each injection, perform a safety test before each dose, rotate injection sites to prevent lipodystrophy, and never mix Semglee with other insulins in the same syringe.

Correct injection technique is essential for accurate, safe, and consistent insulin delivery. The Semglee pre-filled pen is a disposable, dial-a-dose insulin pen that delivers doses from 1 to 80 units in 1-unit increments. Below is a detailed step-by-step guide for using the pen.

Step-by-step injection guide

1. Prepare the pen: Wash your hands with soap and water. Remove the pen from the refrigerator 15–30 minutes before injection (cold insulin is more painful and may be absorbed more slowly). Remove the pen cap. Check that the insulin solution is clear and colorless – do not use if it is cloudy, discolored, or contains particles
2. Attach a new needle: Tear off the paper tab from a new pen needle. Screw or push the needle straight onto the pen. Remove the outer needle cap (keep it for safe needle disposal) and the inner needle cap (discard). Always use a new needle for each injection to ensure sterility and accurate dosing
3. Perform a safety test: Dial 2 units. Hold the pen with the needle pointing upward and tap the cartridge gently so any air bubbles rise to the top. Press the dose button fully. A drop of insulin should appear at the needle tip. If no drop appears, repeat with a new 2-unit dose until insulin is seen. This removes air bubbles and confirms the pen is working
4. Select your dose: Turn the dose selector to your prescribed dose. You can correct the dose by turning the selector forward or backward without wasting insulin. If you accidentally pass your dose, simply dial back
5. Choose and clean the injection site: Recommended sites are the abdomen (at least 5 cm from the navel), the front or lateral aspect of the thigh, or the upper outer arm. Clean the skin with an alcohol swab and let it dry. Rotate the injection site with each injection, moving at least 1–2 cm from the previous site
6. Inject: Pinch a fold of skin (optional, depending on body fat and needle length). Insert the needle at a 90-degree angle (or at 45 degrees in very lean patients with short needles). Press the dose button fully. Keep the needle in the skin for at least 10 seconds after the dose counter returns to 0 to ensure the full dose is delivered and to prevent insulin leakage
7. Remove and dispose of the needle safely: Pull the needle out of the skin. Using a one-handed "scoop" method, carefully replace the outer needle cap. Unscrew the capped needle from the pen and dispose of it in a designated sharps container. Never recap a needle by holding it with two hands, which increases the risk of needle-stick injury. Replace the pen cap

What Are the Side Effects of Semglee?

The most common side effect of Semglee is hypoglycemia (low blood sugar), affecting more than 1 in 10 users. Other common side effects include injection site reactions, weight gain, and lipodystrophy. Severe allergic reactions are rare but require immediate medical attention. As a biosimilar of Lantus, Semglee has the same safety profile as the reference product.

Like all medicines, Semglee can cause side effects, although not everyone experiences them. The frequency of side effects is classified according to the following international convention: very common (>1 in 10), common (1 in 100 to 1 in 10), uncommon (1 in 1,000 to 1 in 100), rare (1 in 10,000 to 1 in 1,000), and very rare (<1 in 10,000). Understanding these effects will help you recognize them early and seek appropriate care.

Long-term considerations

Insulin glargine has been extensively studied in clinical trials lasting several years, and its safety profile is well established. Large observational studies (including the ORIGIN trial, involving more than 12,000 patients over approximately 6 years) have not shown an increased risk of cancer or cardiovascular events with insulin glargine compared with other treatments. Semglee, as a biosimilar, has demonstrated the same long-term safety profile as the reference product Lantus in comparability studies.

Weight gain is a common effect of all insulin therapy and may be partially managed through diet, regular physical activity, and the addition of weight-neutral or weight-reducing medications (such as metformin, GLP-1 agonists, or SGLT2 inhibitors) when clinically appropriate. Regular follow-up with your diabetes care team should include assessment of HbA1c, weight, blood pressure, lipids, renal function, foot and eye health, and review of injection sites.

If you experience any side effects – including those not listed here – talk to your healthcare provider or pharmacist. You can also report suspected adverse reactions directly to your national pharmacovigilance authority, such as the FDA MedWatch program in the United States, the Yellow Card scheme in the United Kingdom, or the EMA in the European Union. Reporting helps improve drug safety for all patients.

How Should You Store Semglee?

Store unopened Semglee pens in a refrigerator at 2–8°C (36–46°F). Once in use, the pen can be kept at room temperature below 30°C (86°F) for up to 28 days. Do not freeze. Protect from direct light and heat. Do not use insulin that has been frozen or appears cloudy.

Correct storage is critical to maintaining the potency, purity, and safety of insulin. Insulin that has been exposed to inappropriate temperatures may lose effectiveness, leading to unexplained hyperglycemia. Always follow the storage guidelines on the label and discard any insulin that has been improperly stored or shows signs of degradation.

Before first use (unopened)

• Store in a refrigerator at 2–8°C (36–46°F)
• Keep away from the freezer compartment or ice packs – do not freeze
• If Semglee has been frozen, discard it even if it has thawed – freezing damages the insulin
• Keep the pen in its original carton to protect from light
• Check the expiry date on the label – do not use after the stated date

After first use (in-use)

• Store at room temperature below 30°C (86°F); do not refrigerate once in use, as this may cause condensation and alter dosing accuracy
• Use within 28 days (4 weeks) of first use, then discard the pen even if insulin remains
• Always keep the pen cap on when not in use to protect the insulin from light
• Do not store the pen with a needle attached – this can cause air bubbles, insulin leakage, bacterial contamination, and inaccurate dosing
• Do not expose to direct sunlight, excessive heat (such as on a car dashboard, near a heater, or next to a hot-water bottle), or near the freezer

Signs of degraded insulin

Before each injection, visually inspect the insulin solution in the pen. Semglee should be clear and colorless, with no visible particles. Do not use the pen if:

• The solution appears cloudy, thickened, or discolored (yellow, brown, or pink)
• You can see particles, crystals, or floating material in the liquid
• The pen has been dropped or visibly damaged
• It has been stored outside the recommended temperature range
• The expiry date has passed, or more than 28 days have passed since first use

Safe disposal

Used Semglee pens and needles are considered biomedical waste. Dispose of used needles in a puncture-proof sharps container (available from pharmacies or diabetes supply companies). Once the sharps container is full, follow your local guidelines for disposal – in many countries, sharps containers can be returned to pharmacies or collected by municipal waste services. Never place used needles in regular household trash or recycling bins, as this poses a risk of needle-stick injuries to waste handlers.

What Does Semglee Contain?

Each milliliter of Semglee contains 100 units (3.64 mg) of insulin glargine as the active ingredient, along with several excipients including glycerol, zinc, metacresol, polysorbate 20, and water for injections. Each pre-filled pen contains 3 mL of solution (300 units).

Active ingredient

The active substance is insulin glargine, produced by recombinant DNA technology in non-pathogenic strains of Escherichia coli. Each mL contains 100 units of insulin glargine, equivalent to 3.64 mg. Each Semglee pre-filled pen contains 3 mL of solution, corresponding to 300 units of insulin glargine.

Insulin glargine is a structurally modified human insulin analog. Compared with native human insulin, the asparagine at position A21 of the A chain is replaced with glycine, and two arginine residues are added to the C-terminus of the B chain. These modifications shift the isoelectric point to approximately pH 6.7 and allow the formulation to remain fully dissolved at the acidic pH of the injection solution (~pH 4.0) but precipitate slowly at the near-neutral pH of subcutaneous tissue, producing the sustained release profile.

Excipients (inactive ingredients)

The inactive ingredients in Semglee serve specific purposes in maintaining the stability, sterility, and physiological compatibility of the insulin solution:

Physical description and packaging

Semglee is a clear, colorless, aqueous solution supplied in a disposable, pre-filled insulin pen (3 mL, 300 units per pen). The pen is designed for use with standard disposable pen needles (sold separately) compatible with insulin pens. It delivers doses from 1 to 80 units in increments of 1 unit. The dose selector clicks audibly as each unit is dialed, and a dose window clearly displays the selected number of units.

Semglee pens are typically available in packs of 5 pre-filled pens, though pack sizes and availability may vary by country. Semglee is also available as a 10 mL vial in some markets, intended for use with insulin syringes.