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Jennifer Grebow is editor-in-chief of Nutritional Outlook.
By boosting acetylcholine synthesis, a supplement like A-GPC may help counter the “signaling fatigue” that often contributes to muscular fatigue and loss of strength, as well as muscle performance, because acetylcholine helps control speed of muscle contraction.
A-GPC is an important dietary source of choline, one of the key neurotransmitters for brain and memory function. Studies have also explored A-GPC’s (alpha-glycerylphosphorylcholine) ability to influence reaction time in humans, including reaction times related to physical performance.1 While some studies have looked at A-GPC’s influence on endurance, a new study2 suggests that A-GPC supplementation may directly improve lower-body muscle strength.
Published in the Journal of the International Society of Sports Nutrition, the double-blind, placebo-controlled crossover study administered 600 mg daily of Chemi Nutra’s (Austin, TX) AlphaSize A-GPC ingredient for six days to 13 college-age males. Following supplementation, the subjects underwent lower- and upper-body strength tests. For lower-body testing, they participated in an isometric mid-thigh pull test. For upper-body testing, they performed push-up–type tests against a high-frequency load cell.
Strength improved significantly during lower-body testing. Isometric mid-thigh pull peak force improved significantly from baseline compared to placebo. In the upper-body test, the improvement in strength was not statistically significant, which the researchers say may be due to a high variability of upper-body strength among the subjects that may have limited statistical power; however, they said, it is likely there were improvements nonetheless.
The effects on lower-body strength are promising, the researchers wrote. “The results of the study suggest that A-GPC is effective at increasing lower-body force production after six days of supplementation. Given that, in many sports, it is understood that a very small change in performance, often times less than 2%, can significantly affect outcomes, it is important to note that the six days of A-GPC resulted in greater than a 3% increase in lower-body isometric strength.”
The scientists posit that A-GPC’s effects on strength may be due to increasing bioavailable choline. A-GPC is converted to phosphatidylcholine, a precursor to choline, and choline in turn is converted to acetylcholine, a key neurotransmitter. According to Chemi Nutra, “Exhaustive and repeated exercise can compromise motor neuron activity at the neuromuscular junction, and it is believed that motor neurons cannot manufacture and release acetylcholine fast enough to maintain transmission of the action potential from the motor neurons to the muscles.” By boosting acetylcholine synthesis, a supplement like A-GPC may help counter the “signaling fatigue” that often contributes to muscular fatigue and loss of strength, as well as muscle performance, because acetylcholine helps control speed of muscle contraction.
“Given that cholinergic nerves trigger muscle contraction, and that choline availability is linked to acetylcholine synthesis, substances that could augment choline availability might have the potential to influence muscular performance,” the researchers wrote.
Chemi Nutra funded the study. “Chemi Nutra continues to explore how its branded, patented, AlphaSize alpha-glyceryl phosphoryl choline (A-GPC) can improve exercise performance, by focusing on its powerful role in facilitating explosive power output, speeding up reaction time, improving jumping ability, improving eye-hand coordination, and, of course, improving all cognitive measures-focus, memory, learning, and recall,” said Scott Hagerman, president of Chemi Nutra, in a press release.
This is the first test to study the effects of A-GPC directly on isometric strength. The researchers suggested that further studies, including in vitro testing, be done to “demonstrate that A-GPC has the potential to augment neurotransmitter levels in motor neurons.”
Nutritional Outlook magazine