“I wonder if taking something like amino acids after workout would work too?”
Most “muscle building” supplements have a high amount of Creatine, which make the Amino Acids. It is good for your Heart, Brain, and of course Muscles. But... Some have a very high saturated fat/calorie content designed and intended to be burned off with extreme exercise. But you can get just Creatine supplement alone I think.
And eating animal protein after a strenuous work out has been known known for a long time for recovery and also gain.
Eat the protein within 60 minutes of the work out.
Crea5ibe is bad for kidney disease though i think- so cant take it