The oral bioavailability of oxandrolone is 97%.  Its plasma protein binding is 94 to 97%.  The drug is metabolized primarily by the kidneys and to a lesser extent by the liver .   Oxandrolone is the only AAS that is not primarily or extensively metabolized by the liver, and this is thought to be related to its diminished hepatotoxicity relative to other AAS.   Its elimination half-life is reported as to hours but is extended to hours in the elderly.   Approximately 28% of an oral dose of oxandrolone is eliminated unchanged in the urine and 3% is excreted in the feces .