whether EpiPen and Twinject needles are long enough to deliver an epinephrine dose into the muscle

There's some concern about whether EpiPen and Twinject needles are long enough to deliver an epinephrine dose into the muscle.

EpiPen and Twinject are used in emergencies to reverse "anaphylaxis"...a severe allergic reaction that can cause breathing problems, throat swelling, or death.

But the pen needles are only 1/2 to 5/8 inches long. A one inch or longer needle is usually needed to get epinephrine into the muscle...where absorption is fastest.