shot in the arm

shot in the arm (plural shots in the arm)

1. An injection of a drug into the arm, whether for medical or recreational purposes.
2. (idiomatic) A stimulus; a boost in energy, morale, or well-being.
   • 1944 May 1, "Canada at War: Net Profit," Time (retrieved 31 Jan 2017):

     By that agreement, President Roosevelt in 1941 gave Canada's war industry a shot in the arm.

   • 2011 Dec. 30, Robert Booth, "London's Shard: a 'tower of power and riches' looking down on poverty," Guardian (UK) (retrieved 31 Jan 2017):

     Renzo Piano's skyscraper, which will be Europe's tallest building, may provide a shot in the arm for London.

   • 2012 Dec. 4, Annie Lowrey, "Republicans Balk at Short-Term Stimulus in Obama Plan," New York Times (retrieved 31 Jan 2017):

     The president claims the economy needs a shot in the arm now, but Republicans say the nation should not widen the deficit.