Short answer: Both are once-daily long-acting insulins. Lantus (insulin glargine) is taken at the same time every day and lasts 28 days once opened. Tresiba (insulin degludec) can be taken at any time of day in adults, has a half-life of about 25 hours, comes in U-100 and U-200, and lasts 56 days once opened.12 In the Tresiba label trials, HbA1c results were similar to Lantus.
| Lantus (insulin glargine) | Tresiba (insulin degludec) | |
|---|---|---|
| Approved for | Adults and children with diabetes1 | People 1 year and older with diabetes2 |
| When to inject | Once daily at any time, but the same time every day1 | Adults: once daily at any time of day. Children: the same time every day2 |
| Missed dose (adults) | No missed-dose rule in the label1 | Inject during waking hours once noticed, keeping at least 8 hours between doses2 |
| Strengths | U-100 only1 | U-100 and U-2002 |
| Pens | SoloStar: 300 units, 1 to 80 units per injection1 | U-100 FlexTouch: 1 to 80 units. U-200 FlexTouch: 2 to 160 units in 2-unit steps2 |
| Starting dose, type 2 not on insulin | 0.2 units/kg or up to 10 units once daily1 | 10 units once daily2 |
| Dose changes | Individualized1 | Recommended 3 to 4 days between dose increases2 |
| How long it acts | Fairly flat level over 24 hours with no pronounced peak1 | Half-life about 25 hours; steady level after 3 to 4 days; effect lasted at least 42 hours after the last dose2 |
| Opened (in use) | 28 days; pen at room temperature only, vial in or out of the fridge1 | 56 days (8 weeks), in or out of the fridge2 |
| Pump or vein | Not in a pump or into a vein1 | Not in a pump or into a vein2 |
Yes. The Tresiba label reports several randomized, open-label trials against insulin glargine U-100 (Lantus), all designed to show Tresiba was not worse on HbA1c (a 0.4-point margin):2
All met the non-inferiority margin. In plain words: blood sugar control was similar.2
Adults can inject Tresiba at any time of day, and a missed dose can be taken during waking hours as long as at least 8 hours pass before the next one.2 The Lantus label asks for the same time every day and gives no missed-dose rule.1 Children on Tresiba use a fixed time, and a missed pediatric dose is a call to the care team.2
Both labels give dose rules for switching from other insulins and ask for closer glucose checks during and after a change.12 For example, Lantus starts at 80% of the dose when moving from Toujeo or from twice-daily NPH.1 Your diabetes team sets the plan for your own switch.
More detail: how to store Lantus, how to store Tresiba, and what to do if you miss a Lantus dose or miss a Tresiba dose.