It is possible to do bodybuilding at home, but in terms of its effectiveness, gaining mass at home will be inferior to training in a gym. The main reason for this is the impossibility to perform at home (in most cases) such basic exercises as squats and deadlifts. You can't pump up your legs by training at home without squat racks, a barbell and a set of pancakes. Improve shape, strengthen, dry out, yes, pump up in volume - no.

Training at home allows you to bulk up smaller muscle groups (chest, shoulders, broad muscles, biceps, triceps and abs). Even with a small set of equipment, you can pump them without going to the gym. But it will be a localized increase in muscle, to achieve a significant increase in body mass, practicing at home, is extremely difficult.

Conclusion: it is possible to gain mass for a man at home, but doing it in the gym it is much easier, faster and most importantly - the increase in muscle volume will be more significant

Source: https://bestbodyblog.com/pro-nabor-myshechnoj-massy-chestno/