Both Humalog and Novolog are rapid-acting types of insulin used to manage diabetes. But there are important distinctions between Humalog and Novolog, and the drugs are not directly interchangeable.

Humalog and Novolog are two diabetes medications. Humalog is the brand-name version of insulin lispro, and Novolog is the brand-name version of insulin aspart.

These drugs both help manage blood glucose (sugar) in people with type 1 and type 2 diabetes.

Humalog and Novolog are both rapid-acting. That means they work more quickly than other types of insulin.

Check out this comparison so you can work with your doctor to choose an insulin that’s right for you.

Insulin is injected under your skin into the fat. It’s the most common type of treatment for type 1 diabetes because it works quickly.

Humalog and Novolog are both equivalent to the insulin made in your body. Unlike oral diabetes drugs, insulin provides fast relief for changes in your blood sugar.

The type of insulin your doctor prescribes depends on how often and how much your blood sugar fluctuates each day.

The table below provides quick facts at a glance.

What is the generic drug?insulin lisproinsulin aspart
Is a generic version available?yesyes
What does it treat?type 1 and type 2 diabetestype 1 and type 2 diabetes
What form does it come in?solution for injectionsolution for injection
What strengths does it come in?• 3-mL cartridges
• 3-mL prefilled KwikPen
• 3-mL vials
• 10-mL vials
• 3-mL FlexPen
• 3-mL FlexTouch
• 3-mL PenFill cartridges
• 10-mL vials
What is the typical length of treatment?long termlong term
How do I store it?Refrigerate at 36° to 46°F (2° to 8°C). Do not freeze the drug.Refrigerate at 36° to 46°F (2° to 8°C). Do not freeze the drug.

Rapid-acting insulin works quicker than other types of insulin. Humalog and Novolog are in the rapid-acting class of insulin. The American Diabetes Association estimates that both medications start working after 15 minutes.

Humalog and Novolog last 2 to 4 hours and reach their peak after 1 hour.

The exact time frame of the onset, peak, and duration may vary slightly for you. That’s why it’s important to check your blood sugar levels before and after taking Humalog or Novolog.

Also, you must eat within a short time after using either drug. Delaying eating after using rapid-acting insulin could cause hypoglycemia (low blood sugar).

If your doctor prescribes Humalog or Novolog, you’ll likely need long-acting insulin as well. Your doctor will decide your dosage.

Both Humalog and Novolog help lower and stabilize your blood sugar when used as prescribed. But a few differences exist between the drugs.

For example, there are differences in:

  • who can take the drugs
  • when people can take them
  • the dosage

So these drugs aren’t interchangeable.

Novolog can be used by adults and children who are at least 2 years old and who have type 1 or type 2 diabetes.

Adults and most children with type 1 diabetes can use Humalog, but the drug hasn’t been studied in children younger than 3 years old. Adults with type 2 diabetes are sometimes prescribed Humalog, too.

For the best results, you should use Humalog 15 minutes before eating. If that’s not possible, take it right after your meal.

Novolog takes action in the body more quickly than Humalog, so you can take it closer to a meal. The best results are achieved if you take Novolog 5 to 10 minutes before eating.

Both Humalog and Novolog can be diluted. If you need a dose lower than the amount you have, you can dilute either drug with the appropriate diluting medium. Ask your doctor about the correct way to do this.

Both Humalog and Novolog are available as brand-name medications and in generic versions. They cost about the same, but the amount you pay depends on your health insurance coverage.

Both medications are usually covered by health insurance companies and are available at most pharmacies.

Low blood sugar is the most common side effect of Humalog or Novolog. While it’s important to lower your blood sugar levels if you have diabetes, it’s possible for your blood sugar level to get too low.

You should be sure your blood sugar level doesn’t fall below 70 mg/dL.

Other factors can affect your blood sugar level as well, including:

  • your diet
  • exercise habits
  • stress levels

This is why testing your blood sugar as often as your doctor says to is so important.

Other common side effects of Humalog and Novolog include:

  • diarrhea
  • headaches
  • nausea
  • weight gain

Serious side effects can also occur. These can include:

  • reaction at the injection site
  • fluid retention and swelling
  • heart disease
  • low blood potassium levels
  • allergic reactions such as hives, itching, wheezing, difficulty breathing, or swelling in your face
  • fluid retention and swelling (a serious but rare occurrence)

Other medications may interact with Humalog and Novolog. These interactions can cause side effects in your body.

For instance, some interactions may cause your blood sugar level to drop dangerously low.

Other interactions may make Humalog or Novolog less effective. In other words, the drugs won’t work as well to treat your diabetes.

Both Humalog and Novolog interact with the following drugs:

  • high blood pressure drugs, including beta-blockers
  • androgens (male hormones)
  • alcohol

Make sure you tell your doctor about all prescription and over-the-counter drugs, supplements, and herbs you take. This information can help them prevent drug interactions.

You should also tell your doctor about all health conditions you have. Certain medical conditions, such as liver, kidney, and heart disease, may change the way insulin works in your body.

Is Humalog or Novolog better?

Both Humalog and Novolog are effective rapid forms of insulin. They’re administered in the same way and share many of the same side effects, including hypoglycemia — low blood sugar.

Novolog works slightly faster than Humalog and is meant to be taken 5 to 10 minutes before eating. Both medications also have different age requirements.

Talk with a doctor to determine which medication is right for you.

Can I use Humalog or Novolog with alcohol?

You should not use Humalog or Novolog with alcohol. Both of these forms of insulin can interact with alcohol.

You’re more likely to experience low blood sugar if you drink alcohol while taking Humalog or Novolog. If you drink alcohol, talk with a doctor about how much may be safe for you to drink while you’re taking insulin.

What is the difference between insulin lispro and insulin aspart?

While both insulin lispro (Humalog) and insulin aspart (Novolog) are rapid-acting insulin drugs for diabetes, they have important differences, including:

  • Who they’re for. While Novolog is meant to be used by adults and children at least 2 years old with type 1 or type 2 diabetes, Humalog can be used by adults and most children over 3 years old with type 1 diabetes. Sometimes, Humalog may also be prescribed to adults with type 2 diabetes.
  • Timing. Novolog is quicker acting compared with Humalog. Novolog should be taken 5 to 10 minutes before eating while Humalog should be taken 15 minutes before eating.
  • Dosage. Both Humalog and Novolog can be diluted to take a smaller dose, but diluents and instructions may vary.

Can Novolog and Humalog be used interchangeably?

No, Novolog and Humalog cannot be used interchangeably. They have different dosages, timing, and people who can take them.

Rapid-acting insulins such as Humalog and Novolog are most often prescribed for people who have big swings in their blood sugar throughout the day.

Both of these drugs work in similar ways to give your body insulin quickly, but they’re different.

Your doctor can help you decide the best type of rapid-acting insulin for your diabetes.