Athletic Series Dietary Supplement Ornithine alpha-ketoglutarate, or OKG, is a combination of the amino acid ornithine and alpha-ketoglutaric acid (AKG). AKG is an important component in the Krebs cycle, the chief energy-producing cycle in the body. Free-form ornithine is used by athletes and those who want to improve performance. OKG spares muscles the need to break down their BCAA's (branch chain amino acids) in order to generate glutamine, an important energy fuel. Glutamine is generated when AKG combines with ammonia released during intense muscle activity.