A-AKG

The main importance of l-arginine is considered to be its role as a precursor (building material) for the synthesis of NO.1 Supplemental sources of l-arginine are thought to augment nitric oxide production2 , with the result being a measurable increase in blood flow3 (i.e., vasodilatation). The idea is that the beneficial results of this vasodilatation for athletes include increased oxygen transport, delivery of nutrients to skeletal muscle, muscle fiber repair, and improved endurance.
Huntington College of Health Sciences
https://www.huhs.edu/literature/Nitric%20Oxide%20Boosters.pdf

AKG (alpha-ketoglutarate) is the nitrogen-free portion of the amino acids known as glutamine and glutamic acid. It is formed in the Krebs cycle, the energy-producing process that occurs in most body cells. AKG is used by cells during growth and in healing from injuries and other wounds ,1 and is especially important in the healing of muscle tissue.2 A controlled study found that intravenous AKG prevented a decline in protein synthesis in the muscles of patients recovering from surgery .3 , 4 For these reasons, it has been speculated that oral AKG supplements might help improve strength or muscle-mass gains by weightlifters, but no research has been done to test this theory.
Kaiser Foundation
https://wa.kaiserpermanente.org/kbase/topic.jhtml?docId=hn-4451004

A-KIC

Beta-hydroxy-beta-methylbutyrate (HMB) and alpha-ketoisocaproic acid (KIC) are metabolites of leucine. Some researchers have suggested that they also may decrease muscle damage following eccentric exercise. A recent study (van Someren et al. 2005) compared the effects of a HMB (3 g) + KIC (0.3 g) supplement vs. placebo when given daily for 14 days prior to a bout of muscle-damaging eccentric exercise. Muscle damage indices, including CPK and DOMS, were measured pre-exercise and at 1, 24, 48, and 72 hours post-exercise. Compared with placebo, the results indicated that the HMB+KIC supplement significantly decreased CPK activity and DOMS. Thus, the researchers concluded that the HMB+KIC supplement diminished the muscle damage from a single bout of eccentric exercise.
Iowa State University
https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=15817&context=rtd

OKG

Ornithine alpha-ketoglutarate (OKG) is manufactured from two amino acids, ornithine and glutamine. These amino acids are called "conditionally essential." ... Ornithine and glutamine are thought to have anabolic effects, meaning that they stimulate the body to build muscle and other tissues.
Winchester Hospital
https://www.winchesterhospital.org/health-library/article?id=21829

Arginine and ornithine also aid in recovery from chronic stress by quelling tissue breakdown as evidenced by lower UH levels.
J Sports Med Phys Fitness
https://www.ncbi.nlm.nih.gov/pubmed/2770269

L-Arginine HCL

L-arginine is a nonessential amino acid that may play an important role in the treatment of heart disease due to its block arterial plaque buildup, blood clots, platelet clumping, and to increase blood flow through the coronary artery.
Drugs.com
https://www.drugs.com/npc/l-arginine.html