I am taking two to three scoops a day which is 2-3g a day.
I am using Brainvitaminz brand.
The directions say begin with 1/2 scoop in morning and 1/2 scoop at night. which comes to one gram a day to start.
Slowly increase the amount over next two weeks until you reach 2-4grams.
Do not take more than 4grams as it has not been studied.
Sarcosine has a short term effect 1-4 hours and longer term effect over a period of six months or more.