Anabolic, anti-catabolic, anti-proteolytic, protein-sparing... These are terms that describe the state of protein affairs in muscle. The bodybuilding community likes to define anabolic compounds as those which increase amino acid shuttling into muscle and increase protein synthesis. Likewise, anti-catabolic, or antiproteolytic (the more specifically correct term) compounds are defined as those which decrease amino acid shuttling out of muscle (also called protein-sparing). Irrespective of whether amino acids are being gained within muscle due to an increase in the influx of amino acids and enhanced protein synthesis, or due to the conservation of amino acids already within muscle, or both, the resulting intramuscular environment is anabolic. This is a really good thing for bodybuilders.