  In F-theory GUTs, threshold corrections from Kaluza-Klein massive modes
arising from gauge and matter multiplets play an important role in the
determination of the weak mixing angle and the strong gauge coupling of the
effective low energy model. In this letter we further explore the induced
modifications on the gauge couplings running and the GUT scale. In particular,
we focus on the KK-contributions from matter curves and analyse the conditions
on the chiral and Higgs matter spectrum which imply a GUT scale consistent with
the minimal unification scenario. As an application, we present an explicit
computation of these thresholds for matter fields residing on specific
non-trivial Riemann surfaces.
