Toujeo (SoloStar & DoubleStar)
Insulin glargine 300 U/mL – ultra-long-acting concentrated basal insulin for diabetes mellitus
Quick Facts About Toujeo
Key Takeaways About Toujeo
- Ultra-long-acting basal insulin: Toujeo provides more than 24 hours (up to 36 hours) of steady background insulin coverage with a flatter action profile and lower within-day variability than insulin glargine 100 U/mL
- Concentrated 300 U/mL formulation: Three times more concentrated than Lantus, which means smaller injection volumes – clinically useful for patients requiring higher insulin doses
- NOT interchangeable unit-for-unit: Dose units are specific to each insulin product. Switching between Toujeo and other insulins must be done under medical supervision with careful titration
- Hypoglycemia is the most common side effect: Always carry a fast-acting source of glucose and learn to recognize early warning signs of low blood sugar
- Never share pens: Sharing insulin pens between patients – even with a new needle – risks transmission of blood-borne infections such as hepatitis B, hepatitis C, and HIV
What Is Toujeo and What Is It Used For?
Toujeo (insulin glargine 300 U/mL) is a concentrated ultra-long-acting basal insulin used to control blood glucose in people with type 1 and type 2 diabetes mellitus. It is injected subcutaneously once daily and works for more than 24 hours, providing steady background insulin that helps regulate glucose levels between meals and overnight.
Toujeo is a pre-filled, disposable insulin pen manufactured by Sanofi. It contains the active substance insulin glargine at a concentration of 300 units per millilitre – three times more concentrated than the original insulin glargine formulation (Lantus 100 U/mL). Insulin glargine is produced by recombinant DNA technology in Escherichia coli bacteria and is structurally modified from human insulin to provide a prolonged, steady release from the subcutaneous injection site.
The higher concentration is not merely a packaging change. When injected subcutaneously, Toujeo forms a more compact depot beneath the skin than Lantus does. Because the depot has a smaller surface area relative to its volume, insulin glargine is released into the bloodstream more slowly and more evenly over time. The clinical result is an ultra-long-acting profile with a lower peak concentration, less within-day variability, and a duration of action that can extend up to 36 hours after injection.
Toujeo is indicated for the treatment of diabetes mellitus in adults, adolescents, and children aged 6 years and older. In type 1 diabetes, it is used as the basal component of a basal-bolus regimen alongside rapid-acting mealtime insulin (such as insulin lispro, insulin aspart, or insulin glulisine). In type 2 diabetes, it can be used alone or in combination with oral antidiabetic medicines (such as metformin, SGLT2 inhibitors, DPP-4 inhibitors, or sulfonylureas) and/or GLP-1 receptor agonists (such as liraglutide, semaglutide, or dulaglutide), depending on the patient's glycemic control needs.
Toujeo is a basal insulin only – it does not cover the rapid post-meal rises in blood glucose. People with type 1 diabetes will always need a separate rapid-acting insulin for meals. People with type 2 diabetes may or may not require mealtime insulin, depending on their treatment stage, beta-cell function, and level of glycemic control.
How does insulin glargine differ from human insulin?
Insulin glargine is a long-acting analog of human insulin. Two modifications distinguish it structurally: the amino acid asparagine at position A21 is replaced by glycine, and two additional arginine residues are added to the C-terminus of the B-chain (positions B31 and B32). These changes shift the isoelectric point of the molecule, making it soluble in the mildly acidic pen solution (pH around 4) but causing it to form microprecipitates upon subcutaneous injection, where the tissue pH is near neutral. The microprecipitates slowly dissolve and release insulin glargine into the circulation over an extended period.
In Toujeo, the same molecule is delivered at a threefold higher concentration. The smaller injection volume for the same number of units creates a more compact and stable microprecipitate, which is absorbed even more slowly than from Lantus. Clinical pharmacokinetic studies have confirmed that steady-state plasma concentrations of insulin glargine are reached after 3–4 days of once-daily Toujeo injections and remain remarkably stable over the 24-hour dosing interval.
Pharmacokinetics at a glance
After subcutaneous injection, Toujeo has an onset of action within 3 to 6 hours, reaches maximum effect gradually without a pronounced peak, and maintains activity for more than 24 hours – up to 36 hours at therapeutic doses. The EDITION clinical program (the pivotal trials supporting Toujeo's approval by the EMA, FDA, and other regulators) demonstrated reduced variability in both pharmacokinetics (exposure) and pharmacodynamics (glucose-lowering effect) compared with Lantus 100 U/mL. This flatter, more predictable profile translates into a lower risk of nocturnal hypoglycemia in many patient populations, a key clinical advantage driving Toujeo's adoption in modern diabetes management.
Insulin glargine is partially metabolized at the subcutaneous injection site to two active metabolites (M1 and M2). Circulating plasma exposure is largely represented by M1, which shares the full biological activity of the parent molecule. Elimination is through the same pathways as native insulin – receptor-mediated uptake and degradation in the liver and kidneys by insulin-degrading enzyme.
Regulatory approval and global availability
Toujeo was first approved in the United States by the FDA in February 2015 and received European Commission authorization via the centralized procedure (EMA) in April 2015. It is now marketed in more than 50 countries under the Toujeo brand. Two pen formats are available: Toujeo SoloStar (1.5 mL, 450 units, delivering 1–80 units per injection in 1-unit steps) and Toujeo DoubleStar (3 mL, 900 units, delivering 2–160 units per injection in 2-unit steps). DoubleStar is particularly suited to patients requiring high daily doses and to those with dexterity challenges who benefit from the larger dose capacity and fewer pen changes.
What Should You Know Before Taking Toujeo?
Before starting Toujeo, tell your healthcare provider about all medical conditions, current medications, allergies, and whether you are pregnant or breastfeeding. Toujeo must not be used during episodes of hypoglycemia, for treating diabetic ketoacidosis, or if you are allergic to insulin glargine or any of its excipients.
Your healthcare provider will consider several clinical factors before prescribing Toujeo, including your type of diabetes, your current insulin regimen, HbA1c target, kidney and liver function, concurrent medications, and lifestyle factors such as meal timing, work schedule, and physical activity. Understanding the following contraindications, warnings, and precautions helps you use Toujeo safely and effectively.
Contraindications
Toujeo must not be used in the following situations:
- Hypersensitivity: Do not use if you have a known allergy to insulin glargine or to any of the excipients (zinc chloride, metacresol, glycerol, water for injections, hydrochloric acid, sodium hydroxide)
- Hypoglycemia: Never inject Toujeo during an active episode of low blood sugar. Treat the hypoglycemia first with fast-acting carbohydrates, then resume your insulin schedule under medical guidance
- Diabetic ketoacidosis (DKA): Toujeo is not indicated for the treatment of DKA. Acute metabolic decompensation requires intravenous short-acting insulin in a hospital setting
Warnings and Precautions
Several clinical situations require special attention and close glucose monitoring when using Toujeo:
- Product identification: Toujeo is 300 U/mL. Errors between Toujeo and Lantus (100 U/mL), or between Toujeo pens and insulin syringes, have been reported. Always check the pen label and never draw Toujeo into a syringe – the dose counter on the pen already displays units of Toujeo
- Switching between insulins: Any change in insulin brand, type, origin (human vs. analog), manufacturer, or strength may require dose adjustment. When switching from insulin glargine 100 U/mL to Toujeo 300 U/mL, patients often need 10–18% more units to maintain the same glycemic control, especially in type 2 diabetes
- Illness, fever, and stress: Infections, fever, surgery, and emotional stress can raise insulin requirements. Concurrent illness with vomiting or reduced food intake may conversely lower requirements. Sick-day rules and more frequent glucose monitoring are essential
- Renal impairment: Insulin requirements may be reduced in people with impaired kidney function because of diminished insulin metabolism. More frequent blood glucose monitoring is recommended
- Hepatic impairment: Liver disease may similarly reduce insulin requirements. Dose adjustments should be individualized and may need to be conservative
- Thiazolidinedione (TZD) combination: Using insulin with pioglitazone may increase the risk of congestive heart failure, particularly in patients with cardiac risk factors. Monitor for signs of fluid retention, swelling, or breathlessness
- Hypokalemia: All insulins can shift potassium from blood into cells, potentially lowering serum potassium. This is clinically relevant in patients taking potassium-lowering drugs (e.g., loop diuretics) or those with baseline hypokalemia
- Injection technique and site rotation: Always rotate injection sites within the same region (abdomen, thigh, or upper arm) to reduce risk of cutaneous amyloidosis and lipodystrophy, both of which can erratically alter insulin absorption
- Never share pens: Even after needle changes, residual blood can remain on pen components. Sharing insulin pens between patients carries a proven risk of hepatitis B, hepatitis C, and HIV transmission
Hypoglycemia is the most common and clinically important adverse effect of insulin therapy. Symptoms include sweating, trembling, rapid heartbeat, hunger, dizziness, confusion, blurred vision, and – in severe cases – loss of consciousness, seizures, or death. Always carry a fast-acting source of glucose (glucose tablets, juice, or sugar) and ensure that people around you know how to help in an emergency. Wearing medical identification (e.g., a diabetes alert bracelet) is strongly recommended.
Pregnancy and Breastfeeding
Toujeo (insulin glargine) can be used during pregnancy when clinically indicated. Large observational cohort studies and meta-analyses of insulin glargine in pregnancy have shown no adverse effects on pregnancy outcomes or fetal development compared with NPH insulin or insulin detemir. Good glycemic control from pre-conception through delivery reduces the risk of congenital malformations, macrosomia, pre-eclampsia, and neonatal hypoglycemia.
Insulin requirements are highly dynamic throughout pregnancy. They typically decrease during the first trimester (increasing the risk of hypoglycemia), then rise progressively during the second and third trimesters due to placental hormones and increasing insulin resistance. Insulin requirements often double by the end of the third trimester and then fall rapidly after delivery – often within hours. Close collaboration with an endocrinologist or diabetologist throughout pregnancy is essential.
Insulin glargine can be used during breastfeeding. Insulin treatment of the mother does not pose a risk to the infant. Even if insulin were present in breast milk in trace amounts, it would be digested in the infant's gastrointestinal tract and not absorbed systemically. However, breastfeeding mothers may experience changes in insulin requirements and should monitor blood glucose carefully, particularly before feeds when hypoglycemia can be more likely.
Driving and operating machinery
Hypoglycemia can impair concentration, judgment, and reaction time. Patients should check blood glucose before driving and periodically during long journeys. If you experience symptoms of hypoglycemia or have blood glucose below 5 mmol/L (90 mg/dL), do not drive until glucose has been restored and maintained for at least 45 minutes. Patients with hypoglycemia unawareness (reduced ability to perceive warning symptoms) require particular caution; national licensing authorities may restrict driving privileges in such cases.
Children and adolescents
Toujeo is approved for use in children aged 6 years and older. Clinical trials (EDITION JUNIOR) established comparable glycemic efficacy and safety to insulin glargine 100 U/mL in this age group. Pediatric dosing should be individualized by a specialist in pediatric endocrinology, with close attention to growth, puberty, and changes in physical activity and nutrition. Toujeo is not recommended below 6 years of age due to limited clinical experience.
How Does Toujeo Interact with Other Drugs?
Many medicines can affect blood sugar levels and may require Toujeo dose adjustments. Drugs that lower blood sugar (e.g., sulfonylureas, GLP-1 agonists, SGLT2 inhibitors) increase the risk of hypoglycemia, while drugs that raise blood sugar (e.g., corticosteroids, thyroid hormones, diuretics) may reduce Toujeo's effectiveness.
Drug interactions with insulin can be clinically significant because they may alter your blood glucose levels, potentially causing dangerous hypoglycemia or unexpected loss of glycemic control. It is essential to inform your healthcare provider about all medications you are taking, including prescription drugs, over-the-counter medicines, vitamins, herbal supplements, and recreational substances. Below is a clinically relevant summary of the most important interactions.
Major Interactions – Increased Risk of Hypoglycemia
The following medicines may increase the blood-sugar-lowering effect of Toujeo, meaning your insulin dose may need to be reduced to avoid hypoglycemia:
| Drug / Drug Class | Examples | Mechanism | Clinical Advice |
|---|---|---|---|
| Sulfonylureas | Glimepiride, glipizide, glyburide, gliclazide | Stimulate pancreatic insulin secretion | Significant hypoglycemia risk; dose reduction of one or both agents commonly needed |
| GLP-1 receptor agonists | Liraglutide, semaglutide, dulaglutide, exenatide | Enhance glucose-dependent insulin secretion and slow gastric emptying | Effective combination in type 2 diabetes; basal insulin dose often reduced 10–20% when initiating |
| SGLT2 inhibitors | Empagliflozin, dapagliflozin, canagliflozin | Increase urinary glucose excretion | Dose reduction may be needed; monitor for euglycemic ketoacidosis |
| ACE inhibitors | Enalapril, ramipril, lisinopril, perindopril | May improve insulin sensitivity | Monitor blood glucose when starting or stopping therapy |
| Salicylates (high dose) | Aspirin at anti-inflammatory doses | Increase peripheral glucose utilization and insulin secretion | Relevant only at anti-inflammatory doses (typically >3 g/day); low-dose aspirin is not an issue |
| MAO inhibitors | Selegiline, phenelzine, tranylcypromine | May increase insulin sensitivity | Monitor blood glucose more frequently during and after treatment changes |
| Fluoxetine | Fluoxetine (SSRI antidepressant) | Enhances insulin sensitivity at higher doses | Possible insulin dose reduction on initiation |
| Pentamidine | Pentamidine (antiprotozoal) | May cause hypoglycemia followed by hyperglycemia due to beta-cell toxicity | Bi-phasic response; requires close monitoring and dose adjustments |
Minor Interactions – Reduced Insulin Effect (Hyperglycemia Risk)
The following medicines may reduce the blood-sugar-lowering effect of Toujeo, potentially requiring an increase in insulin dose:
| Drug / Drug Class | Examples | Mechanism | Clinical Advice |
|---|---|---|---|
| Corticosteroids | Prednisolone, dexamethasone, methylprednisolone | Increase hepatic glucose production and insulin resistance | Often need 20–40% insulin dose increase during steroid courses; taper insulin as steroids are tapered |
| Thyroid hormones | Levothyroxine | Increase glucose absorption and hepatic gluconeogenesis | Adjust insulin when thyroid replacement is started, stopped, or dose-adjusted |
| Thiazide diuretics | Hydrochlorothiazide, chlorthalidone, indapamide | Impair insulin secretion and increase insulin resistance | Monitor blood glucose when initiating diuretic therapy |
| Oral contraceptives | Combined estrogen-progestogen pills, progestins | May increase insulin resistance modestly | Check blood glucose when starting, switching, or stopping |
| Sympathomimetics | Salbutamol, terbutaline, epinephrine, pseudoephedrine | Stimulate glycogenolysis and gluconeogenesis | Temporary rise in glucose; adjust if used chronically |
| Atypical antipsychotics | Olanzapine, clozapine, quetiapine, risperidone | Increase insulin resistance, weight gain, and risk of new-onset diabetes | Increased monitoring; dose titration may be needed |
| Danazol | Danazol (anti-gonadotropin) | Reduces insulin sensitivity | Monitor closely; dose increase may be needed |
| Protease inhibitors | Ritonavir, lopinavir (HIV therapy) | Associated with insulin resistance and lipodystrophy | Monitor glucose throughout treatment |
Special Interaction: Beta-Blockers
Non-selective beta-blockers (propranolol, timolol) and cardioselective beta-blockers (metoprolol, atenolol, bisoprolol) do not reliably raise or lower blood glucose, but they can mask the early warning symptoms of hypoglycemia (tremor, tachycardia). Sweating may still occur. Patients on beta-blockers should be extra vigilant for subtle hypoglycemia symptoms and may need to check their glucose more frequently. In selected cases, a cardioselective beta-blocker may be preferred over a non-selective one.
Alcohol can both increase and decrease blood sugar levels. Moderate alcohol consumption – especially on an empty stomach or after exertion – can intensify insulin's blood-sugar-lowering effect and precipitate severe nocturnal hypoglycemia many hours after drinking. If you choose to drink, do so in moderation, always with food, and monitor your blood glucose before bedtime. Heavy drinking should be avoided, and carbohydrate intake may need to be increased. Hypoglycemia symptoms can be mistaken for intoxication, delaying emergency treatment.
What Is the Correct Dosage of Toujeo?
Toujeo dosing is fully individualized by your healthcare provider based on blood glucose readings, HbA1c targets, and clinical response. It is given once daily by subcutaneous injection at approximately the same time each day. Starting doses vary widely: often 0.2 units/kg in insulin-naïve type 2 diabetes, and approximately 50% of total daily insulin as the basal dose in type 1 diabetes.
There is no universal "standard" dose of Toujeo. Your healthcare provider will determine the right starting dose and titrate it over days to weeks based on fasting blood glucose readings, HbA1c results, and your individual response, body weight, and glycemic targets. The following information provides general clinical guidance based on international guidelines (ADA/EASD, NICE, EMA SmPC). Always follow your individualized prescription.
Adults – Type 2 Diabetes
Insulin-Naïve Patients – Starting Dose
Usually 0.2 units per kilogram body weight once daily (or a fixed start dose of 10 units), administered at approximately the same time each day. The dose is then titrated every 3–7 days based on fasting plasma glucose, aiming for a target typically between 4.0 and 7.0 mmol/L (72–126 mg/dL), or as individualized by your clinician.
Switching from Insulin Glargine 100 U/mL (e.g., Lantus)
Toujeo can be initiated at the same number of units as the previous once-daily basal insulin. However, patients typically require 10–18% more units of Toujeo to achieve target fasting glucose. Dose titration over several weeks is usually needed.
Switching from Other Basal Insulins (NPH, detemir, degludec)
Dose conversion varies by source insulin. When switching from twice-daily NPH or detemir to once-daily Toujeo, the total daily dose is typically reduced by approximately 20% in the first days to reduce hypoglycemia risk, then re-titrated. Always individualized and performed under medical supervision.
Maintenance Dose
Highly individual. Many patients stabilize between 20 and 100 units per day. Patients with significant insulin resistance may require higher doses – for this population, Toujeo DoubleStar (up to 160 units per single injection) may be particularly useful to avoid split injections.
Adults – Type 1 Diabetes
Basal Component of Basal-Bolus Regimen
Toujeo typically provides approximately 50% of total daily insulin as the basal component, with the remaining 50% given as rapid-acting insulin at meals. For example, a patient needing 40 units of total daily insulin might use 20 units of Toujeo once daily and divide the other 20 units across three meals. Timing of the daily injection should be consistent – morning or evening, whichever fits the patient's lifestyle.
Children (aged 6 years and older)
Pediatric Dosing
Toujeo is approved for children aged 6 years and older with diabetes mellitus. In type 1 diabetes, Toujeo is used as the basal component alongside rapid-acting mealtime insulin. Dosing is individualized by weight and growth status under specialist pediatric supervision. Typical basal insulin doses in children range from 0.3 to 0.6 units/kg/day depending on age, puberty, activity, and diet.
Elderly
Dose in Older Adults
No specific dose adjustment is required based on age alone. However, more conservative glycemic targets are often recommended in elderly patients (e.g., fasting glucose <8 mmol/L, HbA1c 7.0–7.5%) to minimize hypoglycemia risk – particularly dangerous in older adults because of falls, cardiovascular events, and cognitive impairment. Reduced kidney or liver function, common in this population, may lower insulin requirements. Frequent glucose monitoring and simplified regimens are often beneficial.
Flexible Dose Timing
Toujeo's prolonged duration of action allows flexibility in the timing of the once-daily injection. If needed, the injection time can be moved forward or backward by up to 3 hours from the usual time without compromising glycemic control. This flexibility is clinically useful for patients with irregular schedules, shift workers, or those who occasionally forget their usual dosing time.
Missed Dose
If you miss a dose of Toujeo, take it as soon as you remember, provided it is within 12 hours of your usual injection time. If more than 12 hours have passed, skip the missed dose and take the next scheduled dose as normal. Do not take a double dose to make up for the missed one. Check your blood glucose more frequently after a missed dose, as levels may temporarily rise.
To help avoid missed doses, inject Toujeo at the same time each day. Setting a daily phone alarm or linking the injection to a routine (e.g., brushing teeth before bed, morning coffee) can establish habits that improve adherence. A diabetes diary or mobile app can help track doses and identify patterns.
Overdose
An insulin overdose – intentional or accidental – causes hypoglycemia, which can range from mild (treatable with oral sugar) to severe (requiring assistance, possibly including glucagon injection or emergency care). With Toujeo's prolonged action, hypoglycemia after an overdose may persist for many hours or days, and prolonged monitoring may be necessary.
- Mild hypoglycemia: Eat or drink 15–20 grams of fast-acting carbohydrates (glucose tablets, juice, regular soda, sweets). Recheck blood glucose in 15 minutes; repeat if still low. Follow with a complex-carbohydrate snack if a meal is not due
- Severe hypoglycemia: If the person is unconscious or unable to swallow safely, do not give food or drink by mouth. Administer a glucagon injection (intramuscular, subcutaneous, or nasal spray) if available and trained. Call emergency services immediately. Place the person in the recovery position on their side to prevent aspiration
- Hospital management: Severe or prolonged hypoglycemia usually requires intravenous glucose (e.g., 10% or 20% dextrose) and continuous monitoring until stable. Admission may be needed, particularly with Toujeo's extended duration
If you or someone you know experiences confusion, loss of consciousness, or seizures after taking insulin, call emergency services immediately. Severe untreated hypoglycemia can cause permanent brain damage or death. With Toujeo, hypoglycemia may recur or persist for many hours after initial treatment – continued monitoring is essential.
How Do You Use the Toujeo SoloStar and DoubleStar Pens?
Toujeo is injected subcutaneously (under the skin) into the thigh, abdomen, or upper arm. The SoloStar pen delivers 1 to 80 units in 1-unit steps; the DoubleStar pen delivers 2 to 160 units in 2-unit steps. Always use a new needle, perform a safety test, and rotate injection sites. The dose counter displays units of Toujeo – never convert from other insulins.
Proper injection technique is essential for accurate dosing, safe delivery, and stable blood glucose control. Toujeo SoloStar and DoubleStar are pre-filled, disposable dial-a-dose insulin pens. Below are detailed instructions; always read the Instructions for Use supplied with each pen and follow the training provided by your diabetes nurse or pharmacist.
Step-by-step injection guide
- Prepare the pen: Wash your hands. Remove the pen cap. Check the label to confirm you have Toujeo (not Lantus or another insulin) and that it has not expired. The solution must be clear and colorless – never use it if cloudy, discolored, or containing particles
- Attach a new needle: Wipe the rubber seal with an alcohol swab. Tear off the paper tab from a new compatible pen needle. Screw or push the needle straight onto the pen. Remove the outer needle shield (keep it for later) and the inner cap (discard). A new needle is essential for every injection
- Perform a safety test: Dial 3 units for SoloStar (or 4 units for DoubleStar). Hold the pen with the needle pointing up and tap gently to move any air to the top. Press the dose button fully. A drop of insulin should appear at the needle tip. Repeat if necessary. This confirms the pen is working and removes air
- Select your dose: Turn the dose selector to your prescribed number of units. SoloStar dials in 1-unit increments (1–80 units per injection); DoubleStar dials in 2-unit increments (2–160 units per injection). The dose can be corrected forward or backward without wasting insulin
- Choose and clean the injection site: Clean the skin with an alcohol swab. Recommended sites are the abdomen (at least 5 cm from the navel), the front of the thigh, or the upper arm (outer aspect). Rotate sites within the same region to prevent lipodystrophy and cutaneous amyloidosis
- Inject: Insert the needle into the skin at the angle recommended by your nurse (typically 90 degrees with shorter needles). Press the dose button all the way in. Keep the needle in the skin for at least 10 seconds after the dose counter returns to 0. The concentrated 300 U/mL solution needs this additional time to fully deliver
- Remove and dispose safely: Pull the needle out of the skin. Carefully replace the outer needle shield, unscrew the needle, and dispose of it in a sharps container. Replace the pen cap. Never store the pen with a needle attached – this causes air ingress, leakage, and potential dose inaccuracy
- Record your dose: Note the time and dose in your diabetes diary or app. This makes pattern analysis with your healthcare team more effective and identifies any issues early
Always rotate your injection site within the same body region. Each successive injection should be at least 1–2 cm from the previous one. Repeated injections in the same spot can cause lipohypertrophy (fat thickening) or, more rarely, cutaneous amyloidosis – both can unpredictably alter insulin absorption, leading to erratic glucose control. A systematic rotation pattern (e.g., "quadrants" of the abdomen across days of the week) is simple and effective.
DoubleStar was designed for patients requiring high basal insulin doses. It holds twice the insulin of SoloStar (900 vs 450 units) and delivers up to 160 units in a single injection, eliminating the need for split doses. This can reduce pen usage, simplify dosing, and improve adherence. It is particularly valuable for patients with dexterity limitations, type 2 diabetes with insulin resistance, or those using basal-bolus regimens with large basal components.
What Are the Side Effects of Toujeo?
The most common side effect of Toujeo is hypoglycemia (low blood sugar), affecting more than 1 in 10 users. Other side effects include injection site reactions, lipodystrophy, and rarely allergic reactions. Most side effects are manageable with correct technique and dose titration, but severe hypoglycemia and serious allergic reactions require immediate medical attention.
Like all medicines, Toujeo can cause side effects, although not everyone experiences them. Side effect frequencies below are classified according to the internationally agreed CIOMS/MedDRA conventions. Understanding the range of potential effects helps you recognize them early and seek appropriate care.
Very Common
- Hypoglycemia (low blood sugar) – symptoms include sweating, trembling, hunger, dizziness, palpitations, confusion, blurred vision, weakness, tingling of lips/tongue, and in severe cases, loss of consciousness or seizures. Early recognition and treatment are key
Common
- Injection site reactions – redness, swelling, itching, pain, or bruising at the injection site; usually mild and resolve within a few days
- Lipohypertrophy – thickening of fat tissue at frequently used injection sites; prevented by systematic rotation
Uncommon
- Lipoatrophy – thinning of fat tissue at injection sites; far less common with modern insulin analogs than with older insulins
- Allergic reactions – skin rash, hives (urticaria), or itching spreading beyond the injection site; sometimes associated with chest tightness or wheezing
- Peripheral edema – mild swelling of ankles or feet, particularly when insulin therapy is initiated or intensified; usually temporary and self-limiting
Rare
- Severe allergic reactions (anaphylaxis) – generalized rash, swelling of the face, lips, or throat, difficulty breathing, low blood pressure, collapse; requires immediate emergency treatment
- Visual disturbances – temporary blurred vision, especially during rapid changes in glycemic control; usually resolves within weeks as the lens of the eye re-equilibrates
- Diabetic retinopathy progression – in patients with pre-existing retinopathy, rapid improvement of glycemic control can transiently worsen the condition; regular eye review is recommended
- Cutaneous amyloidosis – localized amyloid deposits at repeatedly injected sites; can cause erratic insulin absorption. Prevented by site rotation
- Dysgeusia – altered taste sensation; typically mild and transient
- Myalgia – muscle pain; mechanism unclear and usually self-limiting
Seek emergency medical care if you experience signs of a severe allergic reaction (difficulty breathing, facial or throat swelling, fast heartbeat, low blood pressure) or severe hypoglycemia (loss of consciousness, seizures, inability to swallow). Call emergency services immediately.
Hypoglycemia profile – clinical trial evidence
The EDITION clinical trial program (more than 3,500 patients) compared Toujeo with insulin glargine 100 U/mL (Lantus) in type 1 and type 2 diabetes. Toujeo demonstrated non-inferior glycemic control (HbA1c reduction) with a clinically meaningful reduction in nocturnal hypoglycemia – a particularly important endpoint, since nocturnal events can go unrecognized and are associated with cardiovascular risk. In type 2 diabetes, nocturnal hypoglycemia risk was reduced by approximately 21–38% in the first 8 weeks and remained favorable across the 6-month treatment period.
Long-term considerations
Weight change is a known consequence of insulin therapy. In the EDITION trials, weight changes with Toujeo were comparable to or slightly less than with insulin glargine 100 U/mL. Antibodies to insulin glargine may develop in some patients but have not been shown to compromise glycemic control or safety in clinical practice.
Long-term real-world evidence (over 5 years in some registries) has supported the safety profile of Toujeo with no new safety signals. As with all insulins, continued attention to site rotation, pen hygiene, and regular review of technique helps maintain optimal outcomes over time.
If you experience any side effects, even those not listed here, talk to your healthcare provider or pharmacist. You can also report side effects to your national pharmacovigilance authority – for example, the FDA MedWatch program in the United States, the Yellow Card scheme in the United Kingdom, or the EMA adverse reaction database in the European Union. Reporting helps improve the safety of medicines for all users.
How Should You Store Toujeo?
Store unopened Toujeo pens in a refrigerator at 2 to 8 degrees Celsius. Do not freeze. Once in use, store the pen at room temperature below 30 degrees Celsius for up to 6 weeks (42 days) and do not refrigerate it again. Protect from direct light, heat, and cold.
Proper storage is critical to maintaining the potency and safety of insulin. Insulin that has been improperly stored may lose activity, leading to erratic blood glucose control despite unchanged dose. Follow these evidence-based guidelines carefully.
Before first use (unopened pens)
- Store in the refrigerator at 2–8°C (36–46°F)
- Keep away from the freezer compartment – do not freeze
- Do not use Toujeo if it has been frozen, even if it has since thawed
- Keep the pen cap on to protect from light
- Check the expiry date on the label – do not use past the stated date
- Keep pens in their original carton until ready to use
After first use (in-use pens)
- Store at room temperature below 30°C (86°F) – do not refrigerate again once a pen has been in use
- Use within 6 weeks (42 days) of first use, then discard even if insulin remains
- Always keep the pen cap on when not in use to protect from light
- Do not store with a needle attached – this can cause air ingress, contamination, leakage, and dose inaccuracy
- Do not expose to direct sunlight, excessive heat (e.g., closed cars), or frost
When traveling, always carry insulin in an insulated bag or cooling wallet to protect it from extreme temperatures. During air travel, keep Toujeo in your hand luggage (cabin) – the cargo hold can reach sub-zero temperatures that destroy insulin. Carry a letter from your healthcare provider confirming your need for insulin and supplies, particularly for international trips. Airport security allows diabetes-related medications and supplies in carry-on luggage in most countries.
Signs of degraded insulin
Before each injection, inspect the insulin visually. Toujeo should be a clear, colorless solution. Do not use it if:
- The solution appears cloudy, thickened, or discolored (yellow or brown)
- You can see particles or crystals in the liquid
- The pen has been dropped, cracked, or visibly damaged
- It has been stored outside recommended temperature ranges, particularly if frozen
- It is past its expiry date or has been in use for more than 42 days
Safe disposal
Used pens, needles, and unused expired pens should be disposed of according to local regulations. Used needles must always go into a puncture-resistant sharps container – never in household rubbish or recycling. Pharmacies in many countries accept used sharps containers free of charge. Some municipalities have medication take-back programs for expired medicines. Do not flush insulin or sharps into water systems.
What Does Toujeo Contain?
Each milliliter of Toujeo contains 300 units (10.91 mg) of insulin glargine as the active ingredient, along with several excipients including zinc chloride, metacresol, glycerol, and water for injections. The SoloStar pen holds 1.5 mL (450 units); the DoubleStar pen holds 3 mL (900 units).
Active ingredient
The active substance is insulin glargine, a long-acting insulin analog produced by recombinant DNA technology in non-pathogenic laboratory strains of Escherichia coli. Each millilitre contains 300 units of insulin glargine, equivalent to approximately 10.91 mg. Each Toujeo SoloStar pen contains 1.5 mL of solution (450 units); each Toujeo DoubleStar pen contains 3 mL of solution (900 units).
Excipients (inactive ingredients)
The inactive ingredients in Toujeo support the stability, sterility, and correct pH of the insulin solution:
| Excipient | Function |
|---|---|
| Zinc chloride | Stabilizer – helps maintain insulin structure and stability |
| Metacresol | Preservative – prevents microbial growth after pen first use |
| Glycerol | Tonicity agent – makes the solution isotonic with body fluids |
| Hydrochloric acid | pH adjustment – achieves the acidic pH (~4) needed for insulin glargine solubility |
| Sodium hydroxide | pH adjustment – used as needed to fine-tune the solution pH |
| Water for injections | Solvent – provides the liquid base for injection |
Physical description
Toujeo is a clear, colorless aqueous solution for subcutaneous injection, supplied in pre-filled disposable pens. The SoloStar pen contains 1.5 mL of solution (450 units total), delivers 1 to 80 units per injection in 1-unit increments, and features a tactile and audible dose-setting mechanism. The DoubleStar pen contains 3 mL of solution (900 units total), delivers 2 to 160 units per injection in 2-unit increments, and is designed for patients requiring higher doses.
Both pens are designed for use with compatible disposable pen needles (such as BD Micro-Fine or equivalent) sold separately. Toujeo pens are typically supplied in packs of 3 or 5 pens in most markets; not all pack sizes are available in every country. Toujeo must never be transferred to a syringe or mixed with any other insulin – this would invalidate both dose accuracy and the extended pharmacokinetic profile.
What Toujeo does NOT contain
Toujeo is free of latex (neither the pen components nor rubber stoppers contain natural rubber latex), making it safe for patients with latex allergy. It is gluten-free, lactose-free, and does not contain animal-derived ingredients – insulin glargine is manufactured entirely by bacterial fermentation. This makes Toujeo compatible with most dietary preferences, including vegan and religious dietary requirements.
Frequently Asked Questions About Toujeo
Toujeo (insulin glargine 300 U/mL) is a concentrated ultra-long-acting basal insulin used to control blood sugar levels in adults and children aged 6 years and older with type 1 diabetes, and in adults with type 2 diabetes. It provides more than 24 hours of background insulin coverage and is used once daily as part of a comprehensive diabetes management plan that includes diet, exercise, and blood glucose monitoring.
Both Toujeo and Lantus contain insulin glargine, but at different concentrations. Toujeo is 300 units/mL – three times more concentrated than Lantus (100 units/mL) – which reduces injection volume and produces a flatter, longer-lasting pharmacokinetic profile. Toujeo has a duration of action exceeding 24 hours (up to 36 hours) and clinical trials have shown a lower risk of nocturnal hypoglycemia compared to Lantus. When switching from Lantus to Toujeo, patients often require 10–18% more units to achieve the same glycemic control. The two products are not interchangeable unit-for-unit.
The most common side effect is hypoglycemia (low blood sugar), affecting more than 1 in 10 users. Symptoms include sweating, trembling, hunger, dizziness, palpitations, and confusion. Injection site reactions (redness, swelling, itching) are also common, affecting 1 to 10 in every 100 users. Less common side effects include lipodystrophy, allergic reactions, peripheral edema, and temporary visual disturbances. Severe side effects such as anaphylaxis are rare but require immediate emergency care.
Yes. Toujeo (insulin glargine) can be used during pregnancy when clinically needed. Clinical and observational data have not shown adverse effects on pregnancy outcomes or fetal health. Insulin requirements change markedly during pregnancy – typically decreasing in the first trimester and increasing during the second and third trimesters. Close blood glucose monitoring and regular dose adjustments by your healthcare provider are essential. Toujeo is also compatible with breastfeeding; insulin in breast milk is not absorbed by the infant, though the mother may need dose adjustments as she recovers post-partum.
No. Toujeo must never be mixed or diluted with any other insulin or solution. Mixing would alter its pharmacokinetic properties and destroy the prolonged, steady action that defines its clinical benefit. Toujeo is supplied in pre-filled pens designed exclusively for direct subcutaneous injection. If you use a basal-bolus regimen, inject rapid-acting mealtime insulin with a separate pen or syringe at a different site. Never draw Toujeo into a standard insulin syringe – this is a serious dosing error because the syringe is calibrated for 100 U/mL insulins.
Both pens contain the same insulin glargine 300 U/mL. The difference is in capacity and dose range. Toujeo SoloStar holds 1.5 mL (450 units) and delivers 1 to 80 units per injection in 1-unit steps. Toujeo DoubleStar holds 3 mL (900 units) and delivers 2 to 160 units per injection in 2-unit steps. DoubleStar is designed for patients requiring higher daily doses and simplifies administration by avoiding split injections. Your healthcare provider will choose the pen that best suits your dose requirements and dexterity.
Before first use, store Toujeo in a refrigerator at 2–8°C (36–46°F). Do not freeze. Once in use, store the pen at room temperature below 30°C (86°F) for up to 6 weeks (42 days) – do not return to the refrigerator after first use. Always keep the pen cap on to protect from light. Never store the pen with a needle attached. Discard after 42 days even if insulin remains. If Toujeo has been frozen, exposed to direct sunlight, or left in a hot car, do not use it.
References
This article is based on the following evidence-based sources and international clinical guidelines:
- European Medicines Agency (EMA). Toujeo – Summary of Product Characteristics (SmPC). Last updated 2024. Available at: www.ema.europa.eu
- U.S. Food and Drug Administration (FDA). Toujeo (insulin glargine injection) 300 units/mL – Prescribing Information. Sanofi-Aventis. Available at: www.accessdata.fda.gov
- American Diabetes Association (ADA). Standards of Care in Diabetes – 2024. Diabetes Care 2024;47(Suppl 1). doi:10.2337/dc24-SINT
- Davies MJ, et al. Management of hyperglycemia in type 2 diabetes, 2022. A consensus report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetes Care 2022;45(11):2753-2786.
- Riddle MC, et al. New insulin glargine 300 units/mL versus glargine 100 units/mL in people with type 2 diabetes using basal and mealtime insulin: glucose control and hypoglycemia in a 6-month randomized controlled trial (EDITION 1). Diabetes Care 2014;37(10):2755-2762. doi:10.2337/dc14-0991
- Yki-Järvinen H, et al. New insulin glargine 300 units/mL versus glargine 100 units/mL in people with type 2 diabetes using oral agents and basal insulin: glucose control and hypoglycemia in a 6-month randomized controlled trial (EDITION 2). Diabetes Care 2014;37(12):3235-3243. doi:10.2337/dc14-0990
- Home PD, et al. New insulin glargine 300 units/mL versus glargine 100 units/mL in people with type 1 diabetes: a randomized, phase 3a, open-label clinical trial (EDITION 4). Diabetes Care 2015;38(12):2217-2225. doi:10.2337/dc15-0249
- Danne T, et al. Efficacy and safety of insulin glargine 300 units/mL (Gla-300) versus insulin glargine 100 units/mL (Gla-100) in children and adolescents (6–17 years) with type 1 diabetes: Results of the EDITION JUNIOR randomized controlled trial. Diabetes Care 2020;43(7):1512-1519.
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd list (2023). Insulin preparations listed as essential medicines.
- National Institute for Health and Care Excellence (NICE). Type 1 diabetes in adults: diagnosis and management. NICE guideline NG17. Updated 2022.
- National Institute for Health and Care Excellence (NICE). Type 2 diabetes in adults: management. NICE guideline NG28. Updated 2022.
- Ritzel R, et al. Patient-level meta-analysis of EDITION 1, 2 and 3 studies: glycaemic control and hypoglycaemia with new insulin glargine 300 U/ml versus glargine 100 U/ml in people with type 2 diabetes. Diabetes Obes Metab 2015;17(9):859-867.
- British National Formulary (BNF). Insulin glargine. Royal Pharmaceutical Society and BMJ Group. Updated 2024. Available at: bnf.nice.org.uk
- International Diabetes Federation (IDF). Clinical Practice Recommendations for Managing Type 2 Diabetes in Primary Care. 2017. Available at: www.idf.org
Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, consisting of licensed physicians with specializations in endocrinology, clinical pharmacology, and internal medicine.
Medical Writing
iMedic Medical Editorial Team – specialists in endocrinology and clinical pharmacology with documented academic background and clinical experience in insulin therapy and diabetes management.
Medical Review
iMedic Medical Review Board – independent panel of medical experts who verify all clinical content against international guidelines (ADA, EASD, WHO, EMA, FDA, NICE, IDF).
Evidence standard: All medical claims in this article are based on Level 1A evidence (systematic reviews and meta-analyses of randomized controlled trials) or authoritative regulatory sources (EMA SmPC, FDA prescribing information). Content is reviewed according to the GRADE evidence framework and updated when new major evidence is published.