"This was due to the fact that the only way to obtain it was from the adrenal glands of humans."
Never understood this, at least on a chemical level.
C₉H₁₃NO₃ (Adrenaline) + [O] → C₉H₉NO₃
This oxidation of adrenaline (available synthetically) into C₉H₉NO₃, via an oxidizing agent (e.g., silver oxide or ferric chloride), kicks, at least on paper, the same compound.
Obviously I'm missing something here but not immediately obvious why a synthetic source would face a supply constraint.