d-Deprenyl, also known as or dextro-N-propargyl-N-methylamphetamine, is an MAO-B inhibitor that metabolizes into d-amphetamine and d-methamphetamine and is therefore also a norepinephrine–dopamine releasing agent.

l-Deprenyl, also an MAO-B inhibitor, metabolizes to l-amphetamine and l-methamphetamine, which are both norepinephrine releasing agents.

In contrast, d-deprenyl additionally has dopaminergic effects and has been found to be reinforcing in scientific research, whereas l-deprenyl is not known to have any appreciable psychological reinforcement.

[6][7] In addition to its actions as an MAO-B inhibitor and NDRA, d-deprenyl has been found to bind with high affinity to the σ1 receptor (Ki = 79 nM) similarly to various other amphetamine derivatives.

[8][9] Its l-isomer, selegiline, binds with 3.5-fold lower affinity in comparison.