I discuss the stability of the scalar potential in extensions of the Standard Model with right handed neutrinos at the TeV scale. In particular, I focus my analysis on two minimal extensions: the SM+inverse seesaw mechanism and the minimal U(1)' extension with type-I seesaw. These classes of models are potentially accessible at collider and flavour physics experiments. I show that the requirements of stability of the potential within the perturbative evolution under the renormalization group impose significant constraints on the Yukawa couplings of the right handed neutrinos.