Hoof growth and regeneration is very much an "inside-outside" process. Painting something onto the outside of the hoof won't cause regeneration, the hoof must receive nutrients from the blood stream in order to stimulate growth and repair. Your answer is daily supplementation with Ranvet Hoof Food.
Like every other part of the horse's body, the hoof is a living structure and depends on the nutrients carried to it by the blood stream for its growth, strength and repair. The rate of growth and regeneration of the hoof wall cannot be accelerated by any applications to its surface. Hoof tissue is nerveless and cannot repair itself.
Replacement by way of new growth is the only solution to a damaged hoof. New growth, and the rate of new growth, will be stimulated by the nutrients contained in Ranvet Hoof Food.