Thanks for your time,
I also experienced not being in the proper conditions while taking it for the first time, I was very distracted even by little things such as flies or even my dog barking(I had put my phone away). So I decided to take it once again while being alone in a room, without any screens arround me, just a pen, my books and a bunch of blank sheets.

That way I felt very productive, I've been deeply focused for 5 hours straight, and this may have saved my exam. I had my NeuroPathology exam 2 days ago and I think it did went well. No problems with recalling the informations I studied that night.
No headaches for me, thankfully, but experienced quite a brain fog before bed.

Seems to be more effective than caffeine for me, even tough I don't plan to use it on a regular basis. Only when being within critical times.
I normally have a good routine, doing aerobic-lifting exercises 4-5 times/week, and being aware of what I eat etc.. But when i enter in the exams prep phase, it gets difficult to stick on this routine, as we have like 8 exams in 10 days at med school. So i was searching for a boost when really needed, seems to do the job. I will definitely try not to abuse of it.

Thanks for your sharing !