You can substitute a big concentration of energy (the concentration part is important) to some extent. However the energy usage of a computer (the simplest example of a device that lowers entropy in a flexible way) is many orders of magnitude higher than the theoretical limit.

So I'm not entirely sure how many bits of entropy it takes to reverse ageing, but just the computational power required may release enough heat to melt a few cities. And that's before figuring out how to practically do anything (though arguably with enough computing power you can probably just do some advanced version of percussive maintenance).

Edit: Huh turns out the Landauer limit at room temperature is more or less the reciprocal of Avogadro's constant, so the theoretical limits could be within the realm of what's humanly possible. Still it means you probably need a couple of Watts per bit of information for each molecule, divided by however efficient the system processing the hundreds of zettabytes is.

There was a study probably cited by Sinclair in his Lifespan book with mice genetically engineered to have 0.5-1 degree less than normal body temperature. And they lived like ~30% or more longer.

Such hypergeneralised physical thought inevitably leads to necrology in the end-point measurements, rather than biology.