Insulins

Insulin aspart: NovoLog, Fiasp

insulin aspart · Rapid-acting (mealtime) insulin · Novo Nordisk

✓Last reviewed · Written by Dr. George Grunberger · Medical review: pending — clinician review in progress · How we review

In short

Insulin aspart is a rapid-acting (mealtime) insulin made by Novo Nordisk, used for mealtime blood sugar control in type 1 and type 2 diabetes. Schedule: with meals. It is prescription-only in the US and Canada.

FormVials, pens, cartridges
How oftenWith meals
United StatesFDA-approved; unbranded insulin aspart is available.
CanadaAvailable in Canada (NovoRapid, Fiasp).
PrescriptionRequired

What it is used for

  • Mealtime blood sugar control in type 1 and type 2 diabetes

Insulin aspart dosage

Per the official label. Your prescriber sets your dose — never change it on your own.

Insulin aspart label dosing schedule
1DoseIndividualized in units by your prescriber
2TimingNovoLog: 5–10 minutes before a meal. Fiasp: at the start of a meal or within 20 minutes after starting

How to take it

Under the skin; also used in pumps.

Storage

Unopened: refrigerate. In use: room temperature up to 28 days.

How long it works compared with other insulins

How long each insulin type worksApproximate duration of action: rapid-acting about 4 hours, regular about 6 hours, NPH 12 to 18 hours with a peak at 4 to 12 hours, glargine about 24 hours, degludec up to 42 hours, icodec about one week.0 h12 h24 h36 h48 hRapid-acting (lispro, aspart, glulisine)Short-acting (regular)Intermediate (NPH)Long-acting (glargine)Ultra-long (degludec)Once-weekly (icodec)≈ 1 week →
Typical time-action profiles from product labels (darker band = peak). Your response can differ — follow your own plan.

Side effects

Common

  • Low blood sugar (hypoglycemia)
  • Injection-site reactions
  • Weight gain
  • Lipodystrophy or skin thickening at repeated injection sites

Serious — get medical help

  • Severe hypoglycemia (confusion, seizures, loss of consciousness)
  • Low potassium (hypokalemia)
  • Fluid retention and heart failure when combined with thiazolidinediones
  • Serious allergic reactions

Who should not use it

  • During an episode of low blood sugar
  • Never share pens or needles, even if the needle is changed
  • Do not switch insulin type, brand or concentration without your prescriber

Cost

See $35 insulin programs and Medicare caps.

GLP-1 cost without insurance →

How to buy Insulin aspart legally

  1. Get a prescription from your doctor or a licensed telehealth provider.
  2. Fill it at a licensed pharmacy, or through the manufacturer's self-pay pharmacy.
  3. Verify any online pharmacy first (US: safe.pharmacy; Canada: your provincial pharmacy college register).

Buying legally in the USA → Buying legally in Canada →

Frequently asked questions

Why is it called NovoRapid in Canada?

Brand names differ by country; the active ingredient is the same insulin aspart.

Also searched as: NovoLog, NovoRapid, Fiasp, aspart, NovoLog FlexPen, fast-acting insulin

Sources

Checked against these primary sources on .

InsulinsInsulin lispro: Humalog, Admelog, Lyumjevinsulin lispro · With mealsInsulinsInsulin glulisine: Apidrainsulin glulisine · With mealsInsulinsInsulin degludec: Tresibainsulin degludec · Once daily
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