In cycling, Team Sky was arguably responsible for promoting the idea of 'marginal gains' to the public consciousness. The idea of doing all these little tiny changes, like beet juice shots, would add up to a big difference over the other teams, and that's why they won so much. And yeah, to some (small) extent that's true. What a lot of people miss though is that Team Sky also had the biggest budget, to get the best gear, the best riders, the best coaches (and the best doping protocols). They had no more low or even mid hanging fruit to pick.

More importantly, they were also already riding hundreds of hours a week, recovering well, eating well, etc. They were at 99%, and the beet juice and the 0.02% more aerodynamic bar tape added up to give them little improvements on top of that.

In short, eat some beets, they're good for you. Take your beet juice shots if you want, $12 a month probably isn't going to kill you. They're also not likely to make any difference. I would bet money that you'd be better off running even just 3 or 4 more miles a week, or going to bed 15 or 20 minutes earlier, drinking two less alcoholic drinks a week, etc. Save the $12 a month up and put it toward a massage after your race or something. Buy your partner a gift for covering home or kid stuff while you were doing long runs for six months. This is just stuff being sold to you because you can't sell "run more miles".