I just recently started using these and holy shit do they work to good.
I took all in a fairly decent dose in the morning on an empty stomach an hour before working.
Caffeine 150mg
+L theanine 100mg(this is to maintain a calm state and not get jittery from caffeine)
+ l tyrosine 500mg(this is to enhance your cognitive functions as this releases dopamine and helps you get motivated and focused for long working sessions)
+50mg modafinil(this helps you get in the flow state promote wakefullness and alertness over longer period of times)
Now keep in mind DO NOT USE THIS REGULARLY
This is a once every week or so stack you should absolutely not abuse this.
Effects- After an hour or so felt the effects kick in like a bus, could think clearly, sat in one place for a long time, was able to concentrate on one piece of information at a time, no fidgeting or mind wandering off, was extremely productive and feeling relaxed like i could do anything. Finished so much work i normally could not have.
Cons- this effect will wear off after some time and you will feel like you have to take this again but do not as your body will start building tolerance insanely quick and you will be left chasing the feeling you initially felt