If you regularly supplement with targeted amino acids for body building or other purposes (i.e. using targeted aminos like l-cysteine, l-arginine, l-tryptophan, etc.), it's a very good idea to periodically supplement with a well-rounded amino supplement like this to fill in the gaps and keep your body's natural homeostasis systems in balance. Because targeted aminos, helpful as they are, have a tendancy to cause depletions in other amino acids (which are all consituents of protein) when you oversupply one specific amino acid over an extended period of time. Supplementing with a broad spectrum amino acid supplement like this one helps counteract this effect. This is a high-quality supplement at a great price; Country Life is one of my favorite, trusted brands & I find these help keep energy levels up and skin healthy. This is also a great supplement for older people who might not follow a healthy/well-rounded diet or who suffer from low appetite. Highly recommended!P.S. Amino Acid supplementation is useful for more than just bodybuilding (can help with heart health, mood, concentration, memory, and much, much more). Here's a very good layman's reference book about individual amino acids, FYI: