Vertex corrections, or form factors, are important building blocks for higher order calculations,
since they describe virtual corrections to the tree level process.
In flavor physics, especially $B$ meson decays, vertex corrections with flavor changes,
and therefore asymmetric mass assignements on the external legs are important.
In these processdings I present recent results for these kind of corrections
focusing on the generic heavy-to-light form factor and the inclusive decay of $b \to s \gamma$.