There are a few for starters. You can find studies supporting both sides of the issue. Some say it's a booster, some say it's just the relief of withdrawal symptoms like in this video, some say the withdrawal is negligible in the first place, some say the withdrawal is real but so is the boost even for those who don't normally drink it... it's not really worth arguing about, but if you've never seen a study to support a view on this that doesn't match your own, you've been pretty selective in your reading (or haven't seen many studies).
There are a couple. You can find studies supporting both sides of the argument, as is to be expected. Some agree with the study in this video, some agree with the studies linked above, some say it's just a withdrawal reliever, some say the withdrawal symptoms are negligible in the first place and it's an active stimulant... it's not really worth arguing over.
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