Yes indeed beetroot is good for muscle building.
Beetroot and beets are very good for you when building muscle and also just to keep your body healthy and give your body energy as well.
Beetroot and beets contain Nitrate which is a chemical naturally occurring in certain foods that is converted into nitric oxide when consumed.
When you get that nitric oxide from the beetroot it raises the nitric oxide levels in your body which helps build muscles.
So if you're on a muscle building goal then drinking beetroot juice or eating beets can help you build that muscle much quicker and easier.