A dose of the potion is believed to last for one hour. While the potion is in effect, you have a 5% chance of getting two logs from a tree instead of one, giving twice as much experience. After all six doses have been consumed, the flask will shatter and disappear. Only the original, six-dose potion is tradeable on the Grand Exchange. Once the potion has been partially drunk, no more doses can be added to it. However, if you wish to decant the flask into potions, you need at most four doses of potion left in the flask and an empty vial, decanting a flask into a vial will still make the flask shatter.