Short answer: Both are once-daily long-acting insulins.12 Adults can inject Tresiba (insulin degludec) at any time of day; Basaglar (insulin glargine) is taken at the same time every day. Tresiba is approved from age 1; Basaglar for adults and children with type 1 diabetes and adults with type 2. Tresiba's trials used insulin glargine U-100, not Basaglar, and neither label compares the two.
| Tresiba | Basaglar | |
|---|---|---|
| Insulin | Insulin degludec1 | Insulin glargine 100 units/mL2 |
| Approved for | People 1 year and older with diabetes1 | Adults and children with type 1 diabetes; adults with type 22 |
| When injected | Adults: once daily at any time of day; children: same time every day1 | Once daily at the same time every day2 |
| Type 2 start, new to insulin | 10 units once daily1 | 0.2 units/kg or up to 10 units once daily2 |
| Switching from another basal insulin | Adults: same unit dose; children: 80%1 | From glargine 100 units/mL: same dose; from glargine 300 units/mL or twice-daily NPH: 80%2 |
| Pens | U-100 FlexTouch up to 80 units; U-200 FlexTouch up to 160 units; also a U-100 vial1 | U-100 KwikPen or Tempo Pen, up to 80 units2 |
| Opened pen lasts | 56 days1 | 28 days2 |
| Missed dose | Adults: inject when found, at least 8 hours from the next; children: call the provider1 | No rule in the label2 |
| Boxed warning | None1 | None2 |
In Tresiba's 52-week type 1 trial against insulin glargine U-100, the HbA1c difference was −0.01% and met the set margin of 0.4%. The label says adults on Tresiba reached control similar to that on Lantus (insulin glargine 100 units/mL) and Levemir.1 Basaglar's type 1 trial compared it with another insulin glargine 100 units/mL product or a non-US insulin glargine, and several of its tables come from trials of that other product.2 Neither label names the other.
Severe low blood sugar was 10.4% to 12.7% of adults with type 1 diabetes in Tresiba trials, and 4% of adults with type 1 diabetes at 52 weeks on Basaglar.12 These numbers come from separate trials with different people, lengths and methods, so they are not a head-to-head comparison.
Both labels say their long action may delay recovery from a low, neither is used in an insulin pump or mixed with other insulins, and both list the usual insulin warnings: never sharing pens, low potassium and fluid retention with TZDs.12 Tresiba dose increases are 3 to 4 days apart, and children who need under 5 units a day use the vial.1
Which, if either, fits is for your prescriber. More detail: Tresiba side effects, Basaglar side effects, the Tresiba and Basaglar dosing schedules, the Tresiba and Basaglar missed-dose pages, the insulin degludec and insulin glargine guides, and Lantus vs Tresiba: how do the two long-acting insulins compare?.