Insulin Degludec is an ultra-long-acting basal insulin analog, sold under the brand name Tresiba, used to control blood sugar in adults and children with diabetes.

What Is Insulin Degludec?

Insulin Degludec (Tresiba) is a prescription insulin made by Novo Nordisk. It belongs to the class of ultra-long-acting basal insulin analogs, meaning it provides a steady, low-level supply of insulin throughout the day and night — for over 42 hours per dose.

Key facts:

• Brand name: Tresiba
• Generic available: No. There is currently no generic or biosimilar version of Insulin Degludec in the US as of 2026.
• Manufacturer: Novo Nordisk
• Drug class: Ultra-long-acting basal insulin analog
• Controlled substance: No
• Combination product: Xultophy (Insulin Degludec + Liraglutide)

Tresiba comes in prefilled FlexTouch pens in two concentrations:

• U-100: 100 units/mL (3 mL pen)
• U-200: 200 units/mL (3 mL pen) — delivers the same dose in half the volume, which is helpful for people who need higher doses

What Is Insulin Degludec Used For?

Insulin Degludec is FDA-approved for:

• Type 1 diabetes mellitus — in adults and children aged 1 year and older
• Type 2 diabetes mellitus — in adults

It's used as a basal (background) insulin to help control blood sugar levels throughout the day. For type 1 diabetes, it's always used alongside a rapid-acting mealtime insulin. For type 2 diabetes, it may be used alone or combined with other diabetes medications.

For more on how Insulin Degludec works in your body, see our mechanism of action guide.

How Is Insulin Degludec Taken?

Insulin Degludec is injected once daily under the skin (subcutaneously). Here's what you need to know about taking it:

• Timing is flexible — You can inject at any time of day, as long as there are at least 8 hours between doses. This flexibility is one of Tresiba's key advantages.
• Injection sites: Thigh, upper arm, or abdomen. Rotate sites to prevent lipodystrophy (skin changes).
• Do not mix with other insulins in the same syringe.
• Do not use intravenously or in an insulin pump.

Typical Dosing

• Type 2 diabetes (adults): Start at 10 units once daily. Your doctor will adjust by 2–4 units every 3–4 days based on your fasting blood sugar.
• Type 1 diabetes (adults): Start at about one-third to one-half of your total daily insulin dose as Tresiba, with the rest as mealtime insulin.
• Children (type 1): Start at about one-third of total daily insulin needs. Your doctor will individualize the dose.

Who Should Not Take Insulin Degludec?

Do not use Insulin Degludec if you:

• Are allergic to Insulin Degludec or any ingredient in Tresiba
• Are currently having an episode of hypoglycemia (low blood sugar)

Use with caution if you have kidney or liver problems — your doctor may need to monitor your blood sugar more closely since insulin clearance can be reduced.

If you're pregnant or breastfeeding, talk to your doctor. Limited data exists, but insulin is a natural hormone and exogenous insulin is generally considered compatible with breastfeeding.

For a full list of side effects, see our Insulin Degludec side effects guide.

How Much Does Insulin Degludec Cost?

Without insurance or coupons, Tresiba costs approximately $300–$500 per box of FlexTouch pens. Here's how to bring that cost down:

• Medicare Part D: Under the Inflation Reduction Act, insulin is capped at $35/month for Medicare enrollees.
• Tresiba savings card: Commercially insured patients may pay as little as $0–$25/month.
• Novo Nordisk Insulin Value Program: Cash-paying patients can get Tresiba for $35 for up to a 3-month supply.
• Patient Assistance Programs: Uninsured or underinsured patients may qualify for free insulin through Novo Nordisk's PAP via NovoCare.

There is no generic or biosimilar version of Insulin Degludec available in the US, so these programs are especially important. For a complete breakdown, see our guide to saving money on Insulin Degludec.

Final Thoughts

Insulin Degludec (Tresiba) stands out for its ultra-long duration (42+ hours), flexible dosing window, and flat glucose-lowering profile. For many people with diabetes, these features translate to more stable blood sugars and a simpler daily routine.

If you're looking to fill a Tresiba prescription, Medfinder can help you find pharmacies near you that have it in stock.