I assume you are trying to say that this is the drug half life? correct?....because there is a difference between a half life and a active life.
Basically a half life is half the dosage after a given time. for example dbol's half life is 6 hours. this basically means that after 6 hours, half of the consumed compound can still be found in your system. So if you take 50mg of dbol in one shot (not recommended)...but in 6 hours you can still find 25mgs in your system.
an active life is the entire time a drug can be traced through drug testing for example.