It depends alot on how long you keep it in your lungs, if ur quickly tokign and exhalin really quick your body isnt taking all the THCl ain sum is bypassed, as far as i know it works liek oxygen. If you take a full deep and long lasting breath, your body can better benifit form the oxygen, because it's had time to appreciate whats in the lungs. So for you cheap fucks like me, who dont liek seeng thier stash deminish quickly, always coment to yoru frerinds "it's better if u hold it in!"

Ha ha!

Cesar