  Some effective field theories exhibit dynamical resonances that, when
properly included, mitigate their bad behaviour at high energies. Unitarization
of the partial wave amplitudes is the preferred method to unveil such
resonances. Interpreting the Einstein-Hilbert theory in the spirit of effective
Lagrangians, we implement the Inverse Amplitude Method and unitarize the
one-loop level graviton-graviton scattering in pure gravity. Due to the
presence of infrared divergences, the analysis requires a careful treatment of
the infrared region and the introduction of infrared regulators, carefully
selected in order to fulfil perturbative unitarity. No evidence of any
graviball is found, in contradiction with a recent study.
