Shot peening is applied more frequently to enhance the tooth root load carrying capacity of gears. As a result of this process, increased compressive residual stresses are incorporated into the material’s surface layer, leading to a significant rise in the tooth root load carrying capacity. An additional requirement of modern powertrains is also the endurance of load cycles into the VHCF range, especially for electrified powertrains and other applications like trains or the power generation sector, e.g. wind turbines. More recent studies have shown that, especially in the VHCF range, shot-peened gears tend to have a crack initiation at a non-metallic inclusion with the formation of a so-called fisheye beneath the surface, which leads to a decrease in the tooth root load carrying capacity. This circumstance is not yet considered in widely used calculation methods such as ISO 6336 for gears, mainly due to limited experimental results for gears tested in the VHCF range. Therefore, this paper presents extensive experimental results regarding tooth root failures in the VHCF range. Four different material batches of three different steel grades are being investigated. The experimental results were obtained by pulsator tests and gear running tests on the FZG back-to-back test rig. Based on the experimental results, a calculation model is derived to consider the weakening effect of non-metallic inclusions on the tooth root load carrying capacity in the VHCF range. Finally, recommendations are given on how the effects could be regarded in standards such as ISO 6336.