ROUTES OF EXPOSURE
Anabolic steroids can be absorbed from the gastrointestinal
tract, but many compounds undergo such extensive first-pass
metabolism in the liver that they are inactive. Those compounds
in which substitution of the 17-carbon protects the compound
from the rapid hepatic metabolism are active orally (Murad and
Haynes, 1985). There are preparations of testosterone that can
be taken sublingually.
Intramuscular or deep subcutaneous injection is the principal
route of administration of all the anabolic steroids except the
17-alpha-substituted steroids which are active orally.