Leaving EpiPen in car can reduce the concentration of adrenaline

A small study has been carried out in Poland to check the concentration of adrenaline after being left in a hot car.

Official advice is to keep an EpiPen stored below 25 °C (77 °F) and do not expose it to extreme heat.


Nine adult dose EpiPens were left in a car on a hot day:

  • Three were left in the glove compartment;
  • Three in the trunk/boot and;
  • Three on a shelf underneath the rear window.

Each of the EpiPens were placed so that the were not under direct sunlight.

The EpiPens were removed after 12 hours and tested.

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The solution appearance in all 9 injectors did not have any significant visual changes. They functioned correctly when injected.

When analysed, the adrenaline concentration had reduced in all nine.



LocationAverage Reduction in

Concentration of Adrenaline

Glove Compartment14.33%




According to the researchers, these changes are unlikely to make the dose ineffective but further research is needed to see if the exposure is progressive or cumulative, i.e if further exposure to high temperatures could reduce the adrenaline concentration even further.

The study clearly shows the importance of making sure you don’t leave your EpiPen or other adrenaline auto-injector in your car or in any other place they are likely to get too hot.


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