Fiasp vs. Novolog: Differences and similarities explained

In this article:

• What is the main difference between Fiasp and Novolog?
• Compare Fiasp vs. Novolog key differences
• Compare Fiasp vs. Novolog conditions treated
• Which is the best Type 2 diabetes medication?
• Coverage and cost comparison
• Compare side effects
• Compare interactions and warnings
• Can you take Novolog and Fiasp together?

In this article

• What is the main difference between Fiasp and Novolog?
• Compare Fiasp vs. Novolog key differences
• Compare Fiasp vs. Novolog conditions treated
• Which is the best Type 2 diabetes medication?
• Coverage and cost comparison
• Compare side effects
• Compare interactions and warnings
• Can you take Novolog and Fiasp together?

Fiasp and Novolog are two brand-name fast-acting insulins used to lower blood sugar levels in people with Type 1 and Type 2 diabetes. They both contain insulin aspart, an insulin analog (slightly modified form of human insulin). Though these two insulins contain the same active ingredient, they differ in how quickly they start working, their current retail prices, and their approval for use in pediatric patients.

What is the main difference between Fiasp and Novolog?

Fiasp and Novolog are very similar. They contain the same active ingredient, insulin aspart, and are used as a bolus: rapid-onset, mealtime insulin used at the start of a meal to prevent blood sugar spikes (versus all-day glycemic control). However, Fiasp’s formulation also contains niacinamide (vitamin B3) for faster absorption and L-arginine to stabilize the formulation. 

“Fiasp and Novolog are both categorized as rapid-acting insulins,” says Angela Ginn-Meadow, RN, registered dietitian, and certified diabetes educator, based in Baltimore, Maryland. “Fiasp is an ultra-fast-acting insulin that begins working within approximately 2.5 minutes, while Novolog takes around 5.2 minutes to start working.”

Fiasp and Novolog are both available in multi-dose vials and injection pens and are administered via subcutaneous injection (under the skin).

Compare Fiasp vs. Novolog key differences
Differences	Fiasp	Novolog
Drug class	Antidiabetic, rapid-acting insulin	Antidiabetic, rapid-acting insulin
Brand/generic status	Brand	Brand
What is the generic name?	Insulin aspart	Insulin aspart
What form(s) does the drug come in?	10 mL vial 3 mL prefilled pen (called Fiasp  Flextouch pen) or 3 mL Fiasp PenFill (for refillable Fiasp NovoPen Echo) 1.6 mL single-patient-use PumpCart cartridges (for insulin pumps)	10 mL vial  3 mL prefilled pen (called Novolog FlexPen) 3 mL penfill cartridge
What is the standard dosage?	Varies	Varies
How long is the typical treatment?	Long-term	Long-term
Who typically uses the medication?	Adult and pediatric patients with diabetes mellitus	Adult and pediatric patients with diabetes mellitus

Both Fiasp and Novolog are approved by the Food and Drug Administration (FDA) for glucose management in people with either Type 1 or Type 2 diabetes. In some cases, fast-acting insulins like Fiasp and Novolog are used together with long-acting or intermediate-acting insulin. 

Compare Fiasp vs. Novolog conditions treated
Condition	Fiasp	Novolog
Type 1 diabetes	Yes	Yes
Type 2 diabetes	Yes	Yes

Which is the best Type 2 diabetes medication?

Fiasp and Novolog are both effective for lowering blood sugar levels in people with Type 2 diabetes. However, Fiasp works slightly faster than Novolog. “In Type 2 diabetes, [Fiasp] begins working about 9 mins faster than Novolog,” says Blair Gingerich, Pharm.D., an ambulatory care pharmacist in northern Indiana and a member of the SingleCare Medical Board. “If a person consistently forgets to take their rapid insulin prior to eating, they may have a very small benefit by choosing Fiasp over Novolog, but it’s really in Type 1 diabetes that a more significant difference was seen.”

One research simulation also found that using Fiasp instead of Novolog in a MiniMed insulin pump increased the time users spent in a healthy blood sugar range. Another clinical study comparing Fiasp and Novolog in hospitalized Type 2 diabetes patients found that, at the four-hour post-meal time point, 45% of Fiasp users maintained a healthy blood sugar level, compared with 36% of Novolog users. 

Ultimately, the most effective diabetes treatment for each person should be determined only by a healthcare professional familiar with their medical condition, history, any other medications they are taking that could interact with Fiasp or Novolog, and the patient’s response to previous treatments for glucose control.

Fiasp vs. Novolog: Insurance coverage and cost comparison

“Novolog is usually more accessible,” Gingerich says. “It’s been around longer, is less expensive, and is more readily covered by insurance companies.” That said, insurance coverage for specific insulins varies by health plan and can change from year to year. Most plans cover insulin, but your policy may offer better coverage for certain insulin products over others. The best way to find out whether your plan covers Fiasp or Novolog is to contact your insurance company directly. According to the American Diabetes Association, most Medicaid beneficiaries can access free insulin; however, the specific insulin product offered varies by state.

Diabetes Coupons & Discount Diabetic Supplies

Patients without insurance coverage for Fiasp or Novolog can save on the cash price of insulin by using SingleCare coupons. For instance, the average retail price of Fiasp is $400 for 1, 10 mL of a 100-unit/mL vial, but using a free SingleCare card or coupon can lower the price to $36. The average retail price of Novolog is lower: $127 for 1, 3mL of a 100-unit/mL pen, but using a SingleCare coupon can lower that price to $29. 

An important note: Novo Nordisk, the manufacturer of both Fiasp and Novolog, has recently begun lowering the retail prices of insulin products.  

Compare Fiasp vs. Novolog cost & coverage
Coverage details	Fiasp	Novolog
Typically covered by insurance?	Yes, but coverage varies by plan	Yes, but coverage varies by plan
Typically covered by Medicare Part D?	Yes, but coverage varies by plan	Yes, but coverage varies by plan
Typically covered by Medicaid?	Yes, but coverage varies by state	Yes, but coverage varies by state
Quantity	1, 10 mL of 100-unit/mL vial	3mL of 100-unit/mL pen
SingleCare cost	$36 at Walgreens	$29 at Kroger

Prescription drug prices often change. These are the most accurate medication prices at the time of publishing in ZIP code 23666 as of Jan. 6, 2026. Click the “SingleCare cost” link to see the latest drug prices.

Novolog vs. Fiasp side effects

Novolog, Fiasp, and other insulins tend to cause similar side effects. The most common side effects of Novolog are hypoglycemia (low blood glucose levels), allergic reactions, local injection site reactions, lipodystrophy, rash, and pruritus. The most common side effects of Fiasp are hypoglycemia, allergic reactions, hypersensitivity, injection or infusion site reactions, lipodystrophy, and weight gain.

Hypoglycemia is the most serious side effect of insulin. People with diabetes and their caregivers learn to watch for early signs of low blood sugar, such as hunger, lightheadedness, and shakiness, as hypoglycemia can become life-threatening if blood sugar levels continue dropping.

It’s essential to familiarize yourself with potential side effects before starting Fiasp, Novolog, or other insulin products. Consult your healthcare provider for a full list of side effects. 

Fiasp and Novolog drug interactions and warnings

Patients with an allergy to insulin aspart or a history of low blood sugar should avoid both Fiasp and Novolog. Fiasp should be avoided by anyone with hypersensitivity to its added ingredients.

Some other medications, including ACE inhibitors and corticosteroids, can impact your body’s blood sugar regulation. Always tell your provider about any over-the-counter or prescription medications you are taking to prevent the possibility of a drug interaction.

There are a few other precautions that are important to know when starting Fiasp or Novolog:

• Never share needles, syringes, or insulin pens.
• Never stop taking insulin without consulting your healthcare provider.
• Know the signs of hypoglycemia. This is important for all insulin users and their caregivers.

While insulin aspart is considered generally safe while pregnant or breastfeeding, it’s still a good idea to tell your prescriber if these apply to you. 

Can you take Novolog and Fiasp together?

“You should not take Fiasp and Novolog together,” Gingerich says. Because both are fast-acting insulins, combining them could cause hypoglycemia (dangerously low blood sugar), per Ginn-Meadow. 

Ultimately, anyone comparing Fiasp versus Novolog should consult with a healthcare professional familiar with their conditions and health history to determine the best medication option. “Your healthcare provider will choose the most suitable insulin based on your lifestyle,” emphasizes Ginn-Meadow.

The SingleCare prices in this article are the most accurate at the time of publishing in ZIP code 23666 as of Jan. 6, 2026. Prices vary by pharmacy. Visit our Fiasp or Novolog coupon pages for updated Fiasp or Novolog prices near you.