What Is Fiasp? Uses, Dosage, and What You Need to Know in 2026

Fiasp is a brand-name, ultra-rapid-acting insulin used to control blood sugar in people with type 1 and type 2 diabetes. Made by Novo Nordisk, Fiasp was FDA-approved on September 29, 2017, and works faster than almost every other mealtime insulin on the market. Here's everything you need to know about Fiasp in 2026.

What Is Fiasp?

Fiasp is the brand name for fast-acting insulin aspart, a rapid-acting insulin analog manufactured by Novo Nordisk. The active ingredient is insulin aspart — the same molecule found in NovoLog — but Fiasp contains two additional ingredients:

• Niacinamide (Vitamin B3): Increases the speed of initial absorption, allowing Fiasp to appear in the bloodstream in approximately 2.5 minutes — roughly twice as fast as standard NovoLog (5.2 minutes).
• L-Arginine: An amino acid added for product stability.

This ultra-fast onset is what makes Fiasp unique: it can be given at the start of a meal or up to 20 minutes after beginning to eat, giving people with diabetes significantly more flexibility than standard rapid-acting insulins that must be given 5–10 minutes before meals.

What Is Fiasp Used For?

Fiasp is FDA-approved to improve glycemic control in adults and children with diabetes mellitus. It is prescribed for:

• Type 1 diabetes: Used as mealtime (bolus) insulin alongside a long-acting (basal) insulin to manage blood sugar throughout the day.
• Type 2 diabetes: When oral medications, diet, and exercise are insufficient, Fiasp may be added to cover meals.
• Insulin pump (CSII) therapy: Fiasp is approved for use in continuous subcutaneous insulin infusion (CSII) systems. Its ultra-rapid action makes it well-suited for pump therapy.
• Pediatric diabetes: Fiasp is approved for children with both type 1 and type 2 diabetes, and has been studied in patients as young as 2 years old.

What Dosage Forms Does Fiasp Come In?

Fiasp is available in several formats, all at a concentration of 100 units/mL:

• Fiasp FlexTouch pen — 3 mL prefilled disposable pen; 5-pack; most convenient for daily injections
• Fiasp PenFill cartridge — 3 mL; used with a reusable NovoPen device; currently more available than FlexTouch
• Fiasp 10 mL vial — used with a standard U-100 insulin syringe; most widely available; cost-effective
• Fiasp PumpCart — 1.6 mL cartridge designed for compatible insulin pumps; maximum 4 days in pump

How Do You Use Fiasp?

Fiasp is injected subcutaneously (under the skin) at the following recommended times:

• At the start of a meal (ideal timing)
• Up to 20 minutes after starting a meal (if needed)

You can inject into the abdomen, thighs, or outer back of the upper arms. Rotate injection sites with each dose to prevent skin problems (lipodystrophy or cutaneous amyloidosis). Never inject into skin that is swollen, bruised, scarred, or damaged.

Fiasp can also be given intravenously in clinical settings under close supervision, and via continuous infusion pumps (CSII). When using an insulin pump, change the reservoir at least every 6 days.

What Are Typical Fiasp Doses?

Fiasp dosing is highly individualized and set by your prescriber based on your blood glucose readings, A1C, diet, activity level, and other factors. General ranges include:

• Type 1 diabetes: Total daily insulin of 0.4–1 unit/kg/day, split roughly 50/50 between basal and mealtime doses
• Type 2 diabetes: Starting mealtime doses are often 4 units per meal, 0.1 units/kg per meal, or 10% of your basal insulin dose
• Typical mealtime dose range: 4–20 units per meal, depending on carbohydrate content and individual insulin sensitivity

Who Should Not Take Fiasp?

Fiasp should not be used by:

• Anyone currently experiencing hypoglycemia (low blood sugar)
• Anyone with a known allergy to insulin aspart or any ingredient in Fiasp (including niacinamide, L-arginine, metacresol, or phenol)

How Much Does Fiasp Cost in 2026?

Without insurance or discount programs, Fiasp can cost approximately $388 per 10 mL vial. With discount cards (GoodRx, SingleCare), the price can drop to $63–$78 per vial. Commercially insured patients can pay as little as $35/month with the Novo Nordisk Savings Card. Medicare patients pay no more than $35/month under the Inflation Reduction Act.

For a full savings guide, see: How to Save Money on Fiasp in 2026. If you're having trouble finding Fiasp at your pharmacy, medfinder can help you locate it.