Axions and axion-like particles, commonly referred to as ALPs here, are among the most popular extensions of the Standard Model. They are as pseudo-Nambu-Goldstone bosons of a high energy global symmetry that is spontaneously broken naturally light and weakly coupled, presenting an interesting alternative to heavy new particles. In this short overview we present how ALPs can be added to the Standard Model. We then show how ALP couplings to SM particles evolve from high to lower energy scales. This scale running generates, independent from the specific UV coupling structure, flavour-changing ALP couplings in the down-type quark sector. Using that flavour-changing processes are experimentally well-constrained, we are then able to derive strong constraints on UV ALP couplings from flavour experiments that are complementary to astrophysics and collider searches. We present our findings in a benchmark scenario where at the UV scale we assume only the coupling to $SU(2)$ gauge bosons to be non-vanishing.