Keep in mind that the above is a tremendously simplified version of what actually happens in your body after a weight training workout. In reality, the process includes more than just your muscles ...

To build muscle mass, you need around 1.2–1.7 grams of protein per kilogram of body weight or 0.5–0.8 grams per pound of body ...

then that would suggest that you’re lifting too heavy.” She suggests choosing a weight that allows you to work for eight-to-12 reps per set, and which leaves your muscles feeling fatigued ...