Alpha-GPC
Product
Focus before cognitive work or workouts
"300 mg to 600 mg of alpha-GPC taken alone will allow people to be more focused, but doesn't tend to make people feel jittery or overstimulated. ... I will routinely take 300 mg of alpha-GPC prior to some cognitive work or prior to a workout."
More source quotes
Focus during swims, cycled to avoid tolerance
"That and alpha GPC. If I take that combination, I am just dialed in and just swimming... Alpha GPC, I know Huberman talks about you have to cycle that. So that I will... You can build up a very quick tolerance to it."
Taken before workouts or cognitive work, about 4 days per week
"Indeed, I use these myself. The most effective one I've found is Alpha GPC. Alpha GPC consumed at dosages of 300 milligrams to 600 milligrams prior to a workout greatly increase one's ability to focus and concentrate."