The body's natural ability to repair supporting connective tissue, including hair, diminishes after the age of 25. Gelatin, being rich in collagen will help rebuild these connective tissue structures.
So, gelatin, biotin, zinc, copper, sugar to improve circulation, vitamin e to inhibit FFAs and iron.
I use copper peptides in my hair for brittleness and discoloration. Within a few applications I was able to add a lot more buoyancy and shine to my hair.