The Chemistry: Steroids and the Liver
by Patrick Arnold, B. Sc.
from Issue No. 1

Oral steroids are considered to be somewhat "toxic" to the liver largely because most of them have an alkyl (methyl or ethyl) group built into the steroid molecule at the 17-alpha position. This changes the 17-beta OH (hydroxyl) from a secondary to an unoxidizable tertiary one, which thwarts the natural hepatic oxidation of the 17-OH group (which, with natural steroids will produce an inert, excreteable 17-keto steroid). This is the major process of metabolic inactivation for androgens. When it's blocked, the liver relies on less efficient, more demanding means of inactivation. Common injectable steroids are formulated to gradually release into the system, where they are hydrolyzed to become a naturally metabolizable secondary 17-beta hydroxyl steroid. That's why common injectable steroids aren't "toxic" to the liver.