Lore for the Lover-Littler product: https://www.furaffinity.net/view/32464183/

I decided, quite sporadically, to do a little lore piece showing what sizes to expect with however many doses you give your car with a lover-littler and what affect that has on time before it wears off. The smaller the vehicle is made the more effort is taken to maintain the atomic compression, so it tends to wear off faster.

Though just to clarify, despite the effect wearing off after a time, it can be staved off with repeated dosages. The wearing off, as stated in the past, happens slowly. So in the act it will be obvious the feeling that the vehicle is slowly re-enlarging at which time a dosage can be given to counter-act it.