Alpha-ketoglutarate (AKG) is a substance produced during the Kreb's cycle, which is a primary process in cells that produces energy. AKG is also involved in the oxidation of fatty acids, amino acids, and glucose. Although produced in the body naturally, this production tends to decline with age (what doesn't?) and some recent studies suggest that it may be a useful supplement to slow the aging process. In this respect, AKG joins a few other substances, such as rapamycin, metformin and others. But unlike those other substances, AKG is a natural substance that is associated with little or no toxicity. While most of the existing studies about AKG involve animals, which don't always apply to human physiology, one recent human study found that humans who ingested an AKG supplement set back their aging by 8 years according to one measure of aging called epigenetic aging.
While much of the information about how AKG affects aging is new, bodybuilders have known about it for years. Supplements that combined AKG with arginine or ornithine have been touted for years as an effective way to help build added muscle mass, increase muscular endurance, and improve blood flow. Indeed, such supplements can be considered the original nitric oxide boosters, mainly because of their contents of arginine and ornithine, nutrient precursors for NO synthesis. Indeed, the advertisements for arginine AKG (AAKG) touted its ability to "extend muscle pump, enhance muscular growth, and develop rock-hard muscles." But the popularity of arginine AKG was considerably dampened by a few studies that cast doubts on the many claims made for the supplement. One such study was published in the Journal of Strength and Conditioning research.
In the study, the researchers recruited 12 men in their early twenties, all of whom regularly spent time lifting weights and engaging in other resistance training, who performed two trials of exercise separated by at least 1 week. One group of men consumed a serving of a nutritional supplement containing 3,700 mg of AAKG both four hours before and 30 minutes before exercising. Half the men consumed a placebo. Before each exercise session, the men sat and rested for 16 minutes before researchers took their blood pressure. Blood pressure was measured again 5 and 10 minutes after the men completed the exercise session. The researchers repeated the procedure at least one week later.
During the exercise session, the men performed three sets each of chin-ups, reverse chin-ups, and push-ups, each time lifting until they could not lift the weights one more time. The men were allowed three minutes of rest between each set of exercises.
When the researchers analyzed the data, they found that the AAKG supplementation did not improve muscle endurance or significantly affect the blood pressure response to anaerobic work. In fact, men in the study who took the supplements performed fewer total chin-ups and total trial repetitions . . .
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