The WHY behind the THIGH..

John Eshelby

For as long as I have been involved with adrenaline auto-injectors, be it commercially responsible for EpiPen in a previous life, to now helping assist schools reliably procure them, one serious issue has always cropped up. "Can I inject into the arm, chest, stomach...?" The list goes on! I was even contacted by a production company once, who were requesting dummy pens to use on a global TV series, we duly sent them some, but, also requested they speak with our medic so they could have training on the correct use, needless to say they ignored our instructions and went for dramatic effect!!


Let me start by saying from the outset "ALL adrenaline auto-injectors are administered in the same place, the mid outer thigh".


Why the mid outer thigh? There are a few reasons why this is the optimal injection site, and they are:

  1. Importantly, this is the safest route

  2. The thigh muscle is one of the largest containing lots of blood vessels, therefore greater the blood supply, the faster absorption of the adrenaline

  3. There is less fat between the skin and muscle in the thigh. Adrenaline needs to be injected straight into the muscle to be most effective

Importantly as well, failure to administer adrenaline quickly during a severe reaction could increase the chance of death, therefore getting it right is essential. Anaphylaxis is severe and life-threatening and is rapid in onset.


So (not that there should be any doubt), you SHOULD NOT, (as films, TV series depict and which was incorrectly demonstrated earlier this year on breakfast TV) plunge an adrenaline auto-Injector into the chest or arm or anywhere else for that matter other than the mid outer thigh this is the correct site to administer an adrenaline auto-injector.

Difference in administration technique between brands of auto-injector.

There are currently 3 devices available on the UK market, EpiPen, Jext & Emerade. Although all are administered at the same place the method of administration varies between brands. For example, with EpiPen, you should jab from approximately 10cm away with the orange tip facing the outer thigh", however, to administer Jext, you should place and push on the outer thigh as demonstrated above. Additionally there are differences in the length of time the device should be held into the outer thigh during the injection and massaging injection site instructions.

For full instructions and training videos for each brand I would advise you visit the manufacturers websites. Training devices are also available to order there.

To see how your device should be administered please click on the links below:

In summary...

ALL adrenaline auto-injectors are administered at the mid outer thigh, however, all have slightly different administration techniques. From time to time GPs may prescribe a different brand of auto-injector therefore keeping up to date with training and practicing with dummy devices is essential. I would also recommend taking a training course… a quick google search will bring up local and national training providers. We also partner with training providers and their details can be found here.


The risk of someone having an anaphylactic reaction is small but being able to save a life would be huge. What you do in those crucial minutes could mean a lifetime to someone else.


Do you know why the auto-injector was developed?

Originally the auto-injector was developed as a device for rapid administration of antidotes to nerve agents during World War II. Inspired by the original device, Sheldon Kaplan invented EpiPen in the 1970’s.


“IF IN DOUBT ADMINISTER AN ADRENALINE AUTO- INJECTOR THEN DIAL 999, ASK FOR AN AMBULANCE AND STATE ‘ANAPHYLAXIS’”