the form of cell damage caused by the "excitotoxins," glutamic
and aspartic acids, the damage seems to require both stimulation, and
difficulty in maintaining adequate energy production. This combination
leads to both calcium uptake and lipid peroxidation. When cells
are de-energized, they tend to activate iron by chemical reduction,
producing lipid peroxidation. This could explain the presence
of chemically active iron, but an actual increase in the iron concentration
suggests that there has been prolonged injury (oxidative stress) to
the cell, with increased production of the heme group, which binds iron.
The most commonly used AAS in medicine are testosterone and its various esters (but most commonly testosterone undecanoate , testosterone enanthate , testosterone cypionate , and testosterone propionate ),  nandrolone esters (most commonly nandrolone decanoate and nandrolone phenylpropionate ), stanozolol , and metandienone (methandrostenolone).  Others also available and used commonly but to a lesser extent include methyltestosterone , oxandrolone , mesterolone , and oxymetholone , as well as drostanolone propionate , metenolone (methylandrostenolone), and fluoxymesterone .  Dihydrotestosterone (DHT; androstanolone, stanolone) and its esters are also notable, although they are not widely used in medicine.  Boldenone undecylenate and trenbolone acetate are used in veterinary medicine .