Despite what is typically promoted about Anavar being "moderate on the endocrine system", there is evidence to the total contrary where research studies have actually demonstrated almost 40% suppression of endogenous Testosterone production and testicular function after only 5 days of use at 15mg per day in healthy young men  For that reason, Anavar should not be taken lightly in the location of reduced and interfered with hormone function. If it can reduce the HPTA (Hypothalamic Pituitary Testicular Axis) after a mere 5 days of use at 15mg per day, it can and will cause total shutdown over weeks of use at higher bodybuilding dosages.
Oxandrolone appears to offer less hepatic stress than other c-17 alpha alkylated steroids. The manufacturer identifies oxandrolone as a steroid that is not extensively metabolized by the liver like other 17-alpha alkylated orals, which may be a factor in its reduced hepatotoxicity. This is evidenced by the fact that more than a third of the compound is still intact when excreted in the urine. 405 Another study comparing the effects of oxandrolone to other alkylated agents including methyltestosterone, norethandrolone, fluoxymesterone, and methandriol demonstrated that oxandrolone causes the lowest sulfobromophthalein (BSP; a marker of liver stress) retention of the agents tested. 406 20 mg of oxandrolone produced 72% less BSP retention than an equal dosage of fluoxymesterone,which is a considerable difference being that they are both 17-alpha alkylated.