One was enough
A single capsule was included as a sample in one of my orders.
I typically take the 100/200mg Caffeine + L-Theanine capsules sold here on occasions where I feel like I can take advantage of them for extra productive days, or if I straight up can not commit to something because of fatigue/malaise.
Going from conventional caffeine via coffee, to those capsules, was more than perceptible and did wonders for my productivity when I wanted/needed it. Typically resulting in what feels like ~4 hours of aid.
Going from those capsules to this one, is like crossing another frontier.
While it wasn't necessarily my intention, I gladly spent all day today working on something I've fallen behind on, and did so with laser focus. Completely isolated in my mind.
I had accomplished so much in the first 40 minutes that it felt like half the day had past when I checked the clock. Yet in retrospect, the day seemed like it went by in an instant. To me this is not a bad impression, it is to say that I had done all of this work and it felt more or less trivial to do so. It didn't feel like "a long day" despite being much more intensive and involving more complex problems than I've had in recent times.
While these will likely see even less frequent use than the formerly mentioned capsules, I am very glad to have them in my arsenal. One was enough to convince me to buy a batch. Superb.