How fast does Rapid insulin start working?

It usually starts lowering blood sugar within 15 minutes of injection.

When is the peak effect?

Peak effect occurs after about 1.5 hours.

Rapid-acting (Analog)

Q: How long does it last?

The total duration of action is around 4 hours.

Rapid-acting insulins start working within 10–15 minutes, peak at around 1–2 hours, and last about 3–5 hours. They are taken right before or immediately after meals.

Onset

min

Fast

Time until it starts working after injection.

Peak

1.5 h

When effect is strongest (may be minimal for some long-acting insulins).

Duration

approx

Total time the insulin continues to act.

Activity curve (illustrative)

This stylized curve shows a typical onset, peak, and duration profile for Rapid insulins. For education only.

How it works

Rapid

Rapid-acting insulins begin to lower blood glucose within about 15 minutes of injection. They reach their peak effect at around 1 to 2 hours and wear off after roughly 3 to 5 hours. They are designed to mimic the quick insulin release that occurs naturally after meals.

Typical use

Usually taken immediately before or right after eating to manage meal-time glucose spikes. Often paired with a long-acting basal insulin as part of multiple daily injection (MDI) therapy or delivered via insulin pump.

Storage & handling

Keep unused insulin refrigerated between 2–8°C. In-use pens or vials can usually be stored at room temperature for up to 28 days, away from sunlight or heat.

Frequently asked questions

When should I take rapid-acting insulin?

How fast does rapid-acting insulin start working and how long does it last?

Do I still need basal insulin if using rapid-acting?

What happens if I inject and then delay my meal?

How should I choose injection sites in India’s hot climate?

Brands

Representative brands you may see in India (not exhaustive).

Novorapid

₹1,017

Manufacturer:: Novo Nordisk
Strength:: 100 IU/mL
Forms:: PenCartridge
Availability:: INUSEU

Storage: Store at 2–8°C. In-use pens may be kept at room temperature for up to 28 days.

Rapid-acting analog insulin aspart for meal-time use.

Humalog

₹1,095

Manufacturer:: Eli Lilly
Strength:: 100 IU/mL
Forms:: PenCartridge
Availability:: INUSEU

Storage: Store at 2–8°C. Do not freeze. In-use stable for 28 days.

Rapid-acting insulin lispro for controlling post-meal glucose.

Apidra

₹871

Manufacturer:: Sanofi
Strength:: 100 IU/mL
Forms:: PenCartridge
Availability:: INUSEU

Storage: Store refrigerated (2–8°C). In-use pen may be kept at room temperature for 28 days.

Rapid-acting insulin glulisine, works quickly to control postprandial spikes.

Fiasp

₹952

Manufacturer:: Novo Nordisk
Strength:: 100 IU/mL
Forms:: PenCartridge
Availability:: INUSEU

Storage: Store at 2–8°C. Stable for 28 days at room temperature after opening.

Ultra-fast insulin aspart with added niacinamide for quicker absorption.

Disclaimer: Information is for general educational use only and not a substitute for medical advice. Always consult your healthcare provider before making any changes to insulin treatment.