Collagen powder on tummy tuck incision?

You will need to wait until all the sutures and tapes are removed. At that point, the incision will be closed and collagen powder may not do much. It is not absorbed through intact skin since it is a large molecule. Scar products are designed to penetrate and improve the scar. I recommend those instead.

I don't think it would hurt to use it but I don't think it will speed recovery. Usually patients are not in short supply of collagen as the body synthesizes it during wound healing. There are literally hundreds of cell signalers, growth factors, proteins and cells that are involved in the wound healing process with collagen only being one of them. The original collagen that is deposited into a wound is fetal collagen.

Imagine you have a factory making a gizmo, and there are many supplies needed to make that gizmo. Now imagine if all of the hundreds of workers are working as fast as they can. They can only make so many gizmos per hour. If you pile a whole bunch of one of one of the supplies needed to make that gizmo it will not increase the speed of the production of gizmos. As long as there are sufficient supplies then the factory will run as fast as it can and adding more product will not increase the speed at which a gizmo can be made.