Back to Syringes and Injection Products GentleJet Injector


The GentleJet injector is specially designed for use by kids with diabetes. The pressure settings for the injection are lower than other jet injectors, thus the GentleJet is better suited to kids. Many people first consider a jet injector because they don't like needles and have heard that jet injectors are painless. We contacted the manufacturer to obtain a GentleJet to see for ourselves.

A company representative came to our home to teach us how to use the GentleJet. He was very knowledgeable about diabetes and the product. The training took about an hour, and was very thorough. A checklist was used to ensure that all topics were covered. If you forget anything, the user's manual is quite good, and the manufacturer operates a 24-hour-a-day 800 number in case you really get stuck.

The GentleJet can deliver from 0.5 to 50 units of insulin. Measuring whole units is easy, since each unit is marked by an indentation in the dialing mechanism. Half units can be dialed in, but there is no indent. Insulin mixtures are prepared just as with a syringe.

Image of a GentleJet Injector
The GentleJet Injector

Components of the Jet

Parts of GentleJet Injector

Ease of Use

A jet injector is not as easy to use as syringes and insulin vials, but it's not that hard, once you practice a few times. Here's the procedure for drawing up and injecting insulin. This assumes you already have the insulin vial holders installed on the insulin vials. You can mix insulins in a jet injector just like in a syringe.

  1. Remove the vial holder cap from the insulin vial or vials and place the insulin vials upright on a table.
  2. Holding the front tube assembly in one hand, dial the power pack assembly clockwise with the other hand until you hear a click or see the red X in the window lens.
  3. Remove the nozzle cap and unscrew the nozzle from the nose.
  4. Keeping the insulin vial pointed upright, screw the vial adapter onto the nose.
  5. Turn the insulin vial and jet injector so that the insulin vial upside down. This will allow the jet injector to load the insulin.
  6. Holding the front tube assembly in one hand, dial the power pack assembly counter-clockwise with the other hand until you dial the desired dose, as seen in the window lens.
  7. Turn the insulin vial and jet injector so that the insulin vial is upright.
  8. Unscrew the vial adapter from the nose and recover the insulin vial with the vial holder cap.
  9. Screw the nozzle back on the nose.
  10. Back off on the injection pressure, if desired, by holding the front tube assembly in one hand and dialing the power pack assembly clockwise with the other hand until you have backed off the desired amount. You may dial back up to six steps (units).
  11. Cock the trigger by holding power pack assembly with one hand and the sliding the tab on the trigger with the other hand clockwise until it clicks.
  12. Holding the injector firmly in one hand, place the nozzle against the skin at a 90 degree angle, applying a small amount of pressure.
  13. Press down on trigger with your thumb to inject the insulin.
  14. Cover the noze with the nozzle cap.
  15. Holding the front tube assembly in one hand, dial the power pack assembly counter-clockwise with the other hand until you dial 40 units, as seen in the window lens. This is the position at which the power spring has no tension on it and is the preferred storage state.

You might be thinking, "Wow. That sounds complicated." A similar list of instructions for standard syringe injections would seem complicated at first too, however. Kids can and do learn how to use jet injectors.

The insulin vials have a special vial holder that must be attached before use. The vial holder can be removed if you need to inject with a needle. Vial holders are used for one vial of insulin and are then discarded with the insulin vial. You must purchase new vial holders for each insulin vial.


I was highly skeptical of the claim made by jet manufacturers that jet injectors are painless. After all, most insulin needles themselves are so small that they are almost painfree themselves. I was in for a pleasant surprise.

We tested the GentleJet on three adults without diabetes and two kids with diabetes, using saline in all cases. For one child, the GentleJet was quite painful at five pressure backoffs, one shy of the lowest pressure setting. She would not allow additional testing. For the other child, it was painless at five backoffs. For all of the adults, the injector was painless at four backoffs.

The sensation of a jet injection is hard to compare with anything. The closest description I can offer is of a "wet" sensation as the liquid enters the skin. I felt absolutely no pain.

Care of the Jet Injector

The jet injector must be sterilized once a week using isopropyl alcohol. The injector comes with a small plastic stand into which you pour the alcohol and soak the front tube assembly and nozzle. There is also a small brush to scrub the nose area with a mixture of warm water and baking soda. This is essential to remove dried insulin deposits from the threaded areas of the nose and nozzle which can cause inconsistent loading and injections results.

The most important instruction for users of jet injectors is not to dry fire the unit. Dry firing is dialing up a large dose of air, rather than insulin, and pressing the trigger. This causes the power assembly to slam into the inside of the nozzle without the cushioning effect of the insulin liquid. Dry firing can damage an injector, and this damage is usually not covered by warranty.


The GentleJet and its related jet injectors, the AdvantaJet and AdvantaJetES, cost $695.00 (Canadian) and $495.00 (US). Some part of the cost may be covered by insurance.

As you consider the cost of the jet, you must compare the cost of syringes over the life of the jet. Using a syringe price of US$0.20 each, and assuming three shots a day, you will spend US$219 per year on syringes. After three-and-a-half years of use, the jet injector will have paid for itself. The warrantly period is only two years, however.


The GentleJet injector is an interesting alternative to traditional needles. For most of our testers, it produced a truly painless injection. For kids who are afraid of needles, or who find needles excessively painful, the GentleJet is a worth a look.

Will we continue to use our GentleJet? Unfortunately no, since the one tester who found it painful is my daughter.

The company representative stated clearly that some people cannot use a jet injector. For some reason, they are not able to find a pressure setting that is comfortable. Activa offers a full refund for these people.

Activa Brand Products Inc.
36 4th Street
Charlottetown, PEI C1E 2B3

The reviews of products are the opinion of children with DIABETES. Each product is reviewed with a single purpose: to determine if the product is suitable for use by children with type 1 diabetes, their parents, and, to a lesser degree, adults with type 1 diabetes. There are many products aimed at adults with type 2 diabetes that are not appropriate or suitable for children or adults with type 1 diabetes.

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