Asymptotically safe theories of gravitation have received great attention in recent times. On the other hand, the consequences of a running Newton constant in astrophysics and cosmology are far from being well understood.
In this talk I shall present a method to encode the information stemming from the flow around the ultraviolet fixed point in a low-energy (planckian!) effective action in a systematic manner. The results will be applied to construct an effective action of inflation which can then be confronted with modern CMB data.