Wikipedia: “Moreover, whereas levoamphetamine is about 3- to 5-fold less potent in terms of dopamine release than dextroamphetamine in vivo, levomethamphetamine is dramatically less potent than dextromethamphetamine and substantially less potent than levoamphetamine in this regard.”
I wonder how l-amphetamine -> l-methamphetamine is rendered less potent by the same chemical change that increases the potency of d-amphetamine -> d-methamphetamine. Very od
Think of the receptors as keyholes and the molecules as keys.
The “correct” side is the right sided keys (D). The Meth-Key is larger and fits the hole nicely. The normal Amphetamine key is a bit smaller. This way it fits less well, but it is easier to fit the “wrong sided” key (L) because it is also smaller.
Now obviously what happens on the molecular level is different, but maybe this helps illuminate, why for one stereo-isomer the one substance is more potent and for the other stereo-isomer it is the other way round.
Its just kinda odd that the dextrorotatory isomer becomes more potent while the levo becomes less so