Know Your Tools - Alpha GPC
As a follow up to caffeine, I want to discuss the neurological ergogenic aid Alpha-GPC. Alpha-GPC is a popular pre workout supplement. It is touted for its ability to increase power output, force production, acute growth hormone release, reaction time, attention and overall cognition.
Alpha-GPC is short for alpha-glycerophosphocholine. It’s a choline molecule attached to a glycerophosphate group. Choline is a precursor of acetylcholine (a very important neurotransmitter in muscle contraction) and phosphatidylcholine (a constituent of cell membranes and pulmonary surfactant).
Alpha-GPC has the greatest oral bioavailability of any choline supplement leading to greater plasma and brain levels of choline. Alpha-GPC is commonly used as a nootropic supplement because of its ability to cross the blood brain barrier and influence neurology & cognition. This nootropic effect has benefits that apply to exercise performance, like improved focus, decision making and reaction time.
Several studies have demonstrated its efficacy in exercise performance (power and force production), however more studies still need to be performed to have a greater understanding into its dosing, mechanisms of action and overall efficacy. It is commonly dosed in the range of 300 - 600 mg taken 30-60 minutes before training.
The mechanism in which Alpha-GPC works isn’t fully understood, however it’s thought that supplementation helps in the maintenance of acetylcholine concentrations during stressors such as exercise. Choline is one of the rate limiting factors in acetylcholine production, therefore having more choline would decrease the likelihood of acetylcholine depletion during training. As mentioned prior, acetylcholine plays an important role in muscle contraction.
Between the motor neuron axon and a muscle fiber, there's a neuromuscular junction (NMJ). When a signal arrives from the axon to the NMJ, an influx of calcium into the synaptic terminal causes the release of thousands of tiny vesicles filled with acetylcholine to be released into the synapse. Acetylcholine then binds to nicotinic receptors at the postsynaptic motor end plate. This causes the nicotinic receptors to open which allows sodium ions to enter the muscle fiber. If enough sodium enters the muscle fiber, a signal is sent throughout the entire fiber that causes the muscle to fire.
In all, Alpha GPC is a supplement that everyone can gain something from, whether that be improvements in cognition, exercise performance or both. Based on how Alpha GPC functions, I recommend using it on training days where force and power production are your main priorities. This does not only apply to lower rep, explosive strength based exercise but to higher rep, high tension, contraction based exercises. Dose between 300 - 600 mg, starting at the lower end and finding your individual sweet spot over time.
As always, it comes down to picking the right tool for the job. If you don’t need assistance in power/force production or cognitive enhancement (volition, attention, reaction time), there's no need for this supplement. You may want to explore other ergogenic aids, such as caffeine. Check out my caffeine article to see if caffeine is something that fits your needs better.
