Im not gaining any more muscle from food. i want to take a supplement. they say pure amino acid pills will do. what is a name of a product that helps?

Avoid supplements.: To build muscle eat more calories than you burn using healthy whole food sources like fruits, vegetables, whole grains, and beans/nuts. You will be getting plenty of protein if you eat a variety of vegetables and legumes. You will of course need to train hard and get enough rest to recover between workouts. Do these things consistently, and you will see results. Many body-builders are vegans now.