Do choline and alpha-GPC make you stronger?

Short answer

No. Strength went up in only one trial of 13 people, and trials of 48 and 20 people found no difference from a fake pill. Too little choline meant smaller strength gains, but eating more than the recommended amount did not add more.

Do choline and alpha-GPC make you stronger?
'Choline → more muscle signal chemical → more strength' — does this formula hold?
Choline is the raw material for acetylcholine, the chemical that tells muscles to move. That is why choline supplements like alpha-GPC go into pre-workouts with claims of more strength and power. We checked the formula step by step.
Does exercise drain your choline?
It dropped in one marathon
A 1992 measurement found blood choline fell about 40% after a 26 km run. That is where the choline story began. But in 20 cyclists, and in 14 people who walked 4 hours carrying 34.1 kg, choline did not run low during exercise.
Does taking it beforehand delay fatigue?
Blood choline rose, endurance did not
When 20 cyclists drank a choline drink, blood choline rose 37~52%, but time to exhaustion was similar to a fake drink. When 14 people drank choline before and midway through a 4-hour march, blood choline rose 128%, yet running and squat results showed no difference.
Did alpha-GPC raise strength?
In 13 people, lower-body pulling force rose by about 10 kg more
13 people took 600 mg of alpha-GPC a day or a fake pill for 6 days, then pulled on a fixed barbell. Force rose 98.8 N (about 10 kg) on alpha-GPC and fell 39.0 N on the fake pill. Upper-body pushing force showed no clear difference. The ingredient maker funded this trial.
What about a bigger group?
In 48 people, strength did not differ
48 people took 250 mg alpha-GPC, 500 mg alpha-GPC, caffeine, or a fake pill for 7 days. Lower-body pulling and upper-body pushing force did not differ among the four groups. Jump speed and power were best in the 250 mg group, but not in the 500 mg group, which took twice as much.
One dose right before training?
No difference in jumps or bench throws
20 people took 315 mg alpha-GPC, 630 mg, or a fake pill on separate days and trained 1 hour later. Jumps, bench press throws and post-workout growth hormone showed no difference. What improved was a focus test score, like naming ink colors.
What if you are short on choline?
Too little meant smaller gains; more than enough added nothing
37 people aged 50 to 69 did 12 weeks of strength training while egg yolk and protein powder set their choline intake. With choline at about 51% of the recommended amount, strength rose 19.4%; at 68% and 118%, it rose 46.8% and 47.4%. Going above the recommended amount did not add more.
Bottom line: choline supplements did not raise strength
The formula breaks at 'more choline → more strength'
Strength went up in only one trial of 13 people; trials of 48 and 20 people found no difference from a fake pill. Taking it beforehand did not help endurance. Not running short on choline from food is enough, and going above the recommended amount did not add strength.