A short video that highlights the nanoinjectors that modify DNA within cells, and programmable zenobots which reproduce themselves inside the body. The second segment in this video is over eight years old, so let this be a bar0menter of how much farther technology has advanced since 2014.
Its quite possible, even probably in many cases, that these “boosters” are merely more programmable zenobots or the food for them, or additional lances to penetrate cells and modify the DNA within them.