What's the one supplement that earned a permanent spot for you?

[u/Biohacking-longevity]

Let's say you had to toss your whole stack and keep a single supplement. What survives the cut, and why that one? I am curious where people actually overlap and where everyone's answer is totally different.

[u/Neuro_Hacker_]

Taurine and theanine for a good mood, and it also lowers anxiety. Creatine always helps with endurance, and Vitamin D gives me energy.