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Insulin glargine U300 (Toujeo)

Sanofi

A concentrated (300 U/mL) once-daily basal analog of insulin glargine. The triple concentration forms a smaller, more compact subcutaneous depot that releases slowly, giving a flatter, longer (>24 h) and more reproducible profile than glargine U100 — and lower hypoglycemia, especially at night, after switching.

Available nowRegulator-approvedbasallong-acting

The scorecard

Onset speed40

Basal-role convention: onset is deliberately slow (action develops over ~6 h on the FDA label) and is not the point for background coverage; scored neutral-low vs basal peers because U300 is even slower to ramp than U100.

Time to peak88

Basal-role convention (flat = good): the compact U300 depot gives a markedly peakless, evenly distributed profile across 24 h — flatter than U100 — scoring high because a basal should have no meaningful peak.

Short tail82

Basal-role convention (long smooth coverage = good, not short): duration exceeds 24 h and reaches up to ~36 h at higher doses, so a single daily dose reliably covers the interval with margin; rare need to split-dose.

Consistency80

Low within-day fluctuation (peak-to-trough <2) and high day-to-day reproducibility (within-subject CV ~17% for exposure) in clamp studies — more predictable than U100, marginally behind degludec.

Exercise flexibility55

Steady, peakless background reduces unexpected lows, but its long >24 h duration means a dose cannot be quickly dialed down for planned activity — scored mid vs basal peers.

Access & cost70

Approved and marketed across US/EU/UK/CA/AU/JP and covered by US capped insulin copay programs, but as a concentrated patented formulation it has NO biosimilar (unlike U100) and costs more per pen than generic glargine.

Insulins are scored relative to their role peers (see tags: rapid, ultra-rapid, basal, inhaled). A basal insulin's onset score compares it to other basals, not to mealtime insulins.

The full picture

Insulin glargine U300 (brand name Toujeo; Lantus XR in Japan), made by Sanofi, is a basal (long-acting) insulin — the steady background insulin that covers you between meals and overnight, not a mealtime insulin.1 It is the same glargine molecule as the original Lantus, but packed at 300 units per millilitre instead of 100 — three times the concentration in a third of the volume.2

Why concentration changes the profile. When you inject glargine it forms a micro-precipitate (a tiny depot) under the skin that dissolves slowly. At triple strength that depot is more compact, with about half the surface area, so it dissolves and is absorbed even more gradually.3 The result is a flatter, peakless, longer profile than U100. On the FDA label the onset of action develops over about 6 hours, the effect is steady with no pronounced peak, and the duration of glucose-lowering exceeds 24 hours — reaching beyond ~36 hours at higher doses.4 Steady state is reached after at least 5 days of once-daily dosing.4 Clamp studies confirm low within-day fluctuation (a peak-to-trough ratio under 2) and high day-to-day reproducibility (within-person variability of exposure around 17%), with measurable activity out to 36 hours.56

Absorption variability. U300 is among the most reproducible basals available — its day-to-day and within-day variability is lower than U100.5 It is, however, slightly behind insulin degludec: in a head-to-head euglycemic-clamp study, degludec had ~37% lower within-day variability and roughly four-fold lower day-to-day variability in glucose-lowering effect than U300.7 In a large clinical-outcomes trial the two performed broadly similarly (more similarities than differences).8 More even absorption is the mechanism behind U300's main clinical benefit: less hypoglycemia, particularly nocturnal, especially in the weeks after switching from another basal.910

A key practical quirk: unit-for-unit, U300 is less potent than U100 — clinical trials needed somewhat higher doses for the same control — so it is not interchangeable one-to-one with Lantus, and doses must be re-titrated when switching.411 It must never be diluted or mixed with other insulins.4

Delivery and exercise. It is injected once daily, at the same time each day, by prefilled disposable pen — the SoloStar (1.5 mL = 450 units) and Max SoloStar (3 mL = 900 units, dialing larger doses in one go).4 Because it is concentrated, the injection volume is small. Its very long, flat action gives steady cover around exercise and reduces surprise lows, but that same long duration means you cannot quickly reduce a dose to pre-empt a planned active day — a limitation shared by all long basals. It is not for diabetic ketoacidosis, which needs rapid insulin.4

Approvals. FDA approved (initial U.S. approval 2015); pediatric use down to age 6 was added in 2019 on the EDITION JUNIOR trial.412 The EU centralised marketing authorisation covers adults and children from age 6,13 and it is approved in Canada (2015), Japan (as Lantus XR, 2015), Australia and the UK.1415

Access and cost. Widely available across the US, EU, UK, Canada, Australia and Japan.1314 In the US it falls under the capped insulin copay programs (manufacturer copay program, uninsured Valyou program, and Medicare Part D).16 The catch: as a patented concentrated formulation it has no biosimilar, unlike U100 glargine (which has biosimilars such as Semglee/Abasaglar), so list prices run higher than generic basal options.17

What's coming. The glargine molecule itself is mature; the active frontier is once-weekly basal insulins (e.g. insulin icodec and efsitora alfa) that aim to replace daily injections entirely — which would make concentrated daily basals like U300 a step toward, rather than the endpoint of, lower-burden background insulin.18

References

  1. Sanofi. TOUJEO (insulin glargine) injection — Highlights of Prescribing Information. DailyMed / U.S. FDA (2015, rev. 2024). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c9561d96-124d-48ca-982f-0aa1575bff36 ↩

  2. Dailey G, Lavernia F. A review of the safety and efficacy data for insulin glargine 300 units/ml, a new formulation of insulin glargine. Diabetes Obes Metab (2015). https://doi.org/10.1111/dom.12531 ↩

  3. Owens DR. Pharmacokinetics and pharmacodynamics of insulin glargine 300 U/mL in the treatment of diabetes and their clinical relevance. Expert Opin Drug Metab Toxicol (2016). https://doi.org/10.1080/17425255.2016.1202916 ↩

  4. Sanofi. TOUJEO / TOUJEO Max (insulin glargine) injection — Full Prescribing Information (Clinical Pharmacology; Initial U.S. Approval 2015). DailyMed / U.S. FDA. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c9561d96-124d-48ca-982f-0aa1575bff36 ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7

  5. Becker RHA, Nowotny I, Teichert L, Bergmann K, Kapitza C. Low within- and between-day variability in exposure to new insulin glargine 300 U/ml. Diabetes Obes Metab (2015). https://doi.org/10.1111/dom.12416 ↩ ↩2

  6. Shiramoto M, Eto T, Irie S, et al. Single-dose new insulin glargine 300 U/ml provides prolonged, stable glycaemic control in Japanese and European people with type 1 diabetes. Diabetes Obes Metab (2015). https://doi.org/10.1111/dom.12415 ↩

  7. Heise T, Nørskov M, Nosek L, Kaplan K, Famulla S, Haahr HL. Insulin degludec: Lower day-to-day and within-day variability in pharmacodynamic response compared with insulin glargine 300 U/mL in type 1 diabetes. Diabetes Obes Metab (2017). https://doi.org/10.1111/dom.12938 ↩

  8. Rosenstock J, Cheng A, Ritzel R, et al. More Similarities Than Differences Testing Insulin Glargine 300 Units/mL Versus Insulin Degludec 100 Units/mL: The Randomized Head-to-Head BRIGHT Trial. Diabetes Care (2018). https://doi.org/10.2337/dc18-0559 ↩

  9. Home PD, Bergenstal RM, Bolli GB, et al. New Insulin Glargine 300 Units/mL Versus Glargine 100 Units/mL in People With Type 1 Diabetes: EDITION 4. Diabetes Care (2015). https://doi.org/10.2337/dc15-0249 ↩

  10. Matsuhisa M, Koyama M, Cheng X, et al. New insulin glargine 300 U/ml versus glargine 100 U/ml in Japanese adults with type 1 diabetes: EDITION JP 1. Diabetes Obes Metab (2016). https://doi.org/10.1111/dom.12619 ↩

  11. Clements JN, Threatt T, Ward E, Shealy KM. Clinical Pharmacokinetics and Pharmacodynamics of Insulin Glargine 300 U/mL. Clin Pharmacokinet (2017). https://doi.org/10.1007/s40262-016-0464-6 ↩

  12. Pace L. FDA expands use of Toujeo to childhood type 1 diabetes (EDITION JUNIOR; pediatric approval to age 6, 2019). MDedge / The Hospitalist (2019). https://blogs.the-hospitalist.org/content/fda-expands-use-toujeo-childhood-type-1-diabetes ↩

  13. European Medicines Agency. Toujeo (insulin glargine 300 units/mL) — EPAR medicine overview; indication in adults, adolescents and children from age 6. EMA (accessed 2026). https://www.ema.europa.eu/en/medicines/human/EPAR/toujeo-previously-optisulin ↩ ↩2

  14. Sanofi Canada. Toujeo: New Basal Insulin Option for Adults Living with Diabetes Approved by Health Canada (Japan approval as Lantus XR also noted). Sanofi (2015). https://sanoficanada.mediaroom.com/2015-06-01-Toujeo-New-Basal-Insulin-Option-for-Adults-Living-with-Diabetes-Approved-by-Health-Canada ↩ ↩2

  15. PR Newswire. Sanofi's Insulin Toujeo now Available for the Treatment of Adults with Diabetes in the UK. PR Newswire UK (2015). https://www.prnewswire.co.uk/news-releases/sanofis-insulin-toujeo-now-available-for-the-treatment-of-adults-with-diabetes-in-the-uk-520578322.html ↩

  16. Sanofi. Toujeo Coverage & Savings — $35/month copay, Valyou uninsured program, Medicare Part D cap. Toujeo.com (accessed 2026). https://www.toujeo.com/coverage-and-savings ↩

  17. American Diabetes Association. Insulin Cost & Affordability (glargine biosimilars Semglee/Abasaglar; U300 has no biosimilar). diabetes.org (accessed 2026). https://diabetes.org/tools-resources/affordable-insulin ↩

  18. Owens DR. Pharmacokinetics and pharmacodynamics of insulin glargine 300 U/mL — context on evolving basal insulin development. Expert Opin Drug Metab Toxicol (2016). https://doi.org/10.1080/17425255.2016.1202916 ↩