Mate, depends on what you want to achieve. If you want arginine to help with the production of GH in the body, then you'll need a higher dosage. If you want it just for NO, then 1000mg twice a day is sufficient. Drink it on an empty stomach, atleast half n hour before meals. I take mine in the morning, and around 3pm. Again, depending on what you are using it for, you can take some just prior to sleeping. It will aid in greater GH production in the body. If this is what you want to use it for, you might want to combine it with orthinine. Same dosage.