As part of our May 2019 STEADFAST RANGER v1.48  update, we've added several new consumables to the game, including the Energy Drink.
A Go! Energy Drink, as found in the world.
The Energy Drink can be used to give the survivor a boost by temporarily restoring depleted Fatigue, and increasing all Stamina (Sprinting, Climbing, and Aiming).
After the boosting effects of the Energy Drink expire, the survivor's Stamina and Fatigue will return to pre-boost levels, followed by a headache.
The Energy Drink can be found in the First Aid tab of the survivor's Inventory and Radial Menu.
An Energy Drink as viewed in the First Aid tab of the Inventory.
The survivor can only have one energy boost active at once.