Are whey or protein-amino acid drinks good for losing weight while working out or more for gaining weight/muscle?

Muscle/Gain Weight?: These are promoted for assisting in building muscle which require the Amino Acid building blocks for muscle protein. The usefulness of whey proteins for promoting this from small clinical trials, is small, maybe a few % over foods. Maintaining muscles does require more daily energy, so to the extent that muscle mass ; strength significantly increase, this might assist reduction in body fat.