How will a supplement like muscle milk help me if I am doing kickboxing?

I am 5'9, 135lbs and very slim, I am currently working out at a local gym, 1 hour cl, kickboxing, cl includes cardio and punching and kicking a 140lbs sand bag, last 15 min is all abs. How will a supplement like Muscle milk help me? will I increase any muscle m? Is this cl all cardio or will I increase muscle size and where? I know that I lot of people will say that I need to lift weights, after 1 hour of this cl there is no energy for anything.