Alpha-GPC
Also known as: L-alpha-glycerylphosphorylcholine, choline alfoscerate, glycerophosphocholine, A-GPC, GPC, alpha-glycerophosphocholine
Alpha-GPC is a water-soluble phospholipid metabolite that delivers choline across the blood-brain barrier more efficiently than choline salts, which is why it anchors many focus and memory formulas and pre-workout blends. About 40 percent of its mass is choline. Randomized studies in healthy adults have used 400 mg per day for two weeks for motivation measures and single 315 to 630 mg doses before cognitive testing; older clinical work at higher amounts was done in medical settings. It is very hygroscopic, so most powders are 50 percent on a silica carrier.
Research summary
Hydrolyzed to choline and glycerophosphate; choline raises acetylcholine synthesis in cholinergic neurons and supplies phosphatidylcholine for membranes, with some evidence of growth hormone release after acute doses.
Dosage
Daily amounts, of compound.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 300 mg | 300–600 mg | 630 mg | — |
Doses are mg alpha-GPC (100 percent basis). Choline content is about 40 percent (104.2 / 257.2), so 600 mg supplies roughly 240 mg choline toward the 3,500 mg choline UL and 550 mg DV. A 2-week single-blind randomized study in healthy volunteers used 400 mg/day (Tamura 2021); an acute crossover in resistance-trained men compared 315 and 630 mg (Kerksick 2024). Typically taken 30 to 60 minutes before mental or physical work. Higher daily amounts were used in older clinical (medical) trials and are not reflected here.
Standardization: 99% alpha-GPC (crystalline) or 50% alpha-GPC on silica
Source material: synthetic or from soy/sunflower lecithin
As supplied: Commonly supplied as a 50% powder on silica (2 mg powder per mg alpha-GPC) because the 99% grade is extremely hygroscopic; set raw material by grade
Forms of Choline
| Form | Typical dose | Element % | Formats | Price |
|---|---|---|---|---|
| Alpha-GPC | 300–600 mg | — | Capsule, Powder, Tablet, Liquid | mid |
| Choline Bitartrate | 250–550 mg | 41% | Capsule, Tablet, Powder, Liquid | low |
| Citicoline (CDP-Choline) | 250–500 mg | — | Capsule, Tablet, Powder, Liquid | high |
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Extremely hygroscopic; 50% grade is standard for capsules and powders. Liquids are feasible since it is water-soluble. Avoid gummies.
Formulation notes
Common in nootropic stacks with huperzine A, bacopa, and caffeine. Count its choline toward the choline UL. Soy-lecithin-derived grades may need allergen review.
Sources
- Alpha-Glycerylphosphorylcholine Increases Motivation in Healthy Volunteers: A Single-Blind, Randomized, Placebo-Controlled Human Study. (Tamura Y, 2021)PubMed
- Acute Alpha-Glycerylphosphorylcholine Supplementation Enhances Cognitive Performance in Healthy Men. (Kerksick CM, 2024)PubMed
- Differential metabolism of choline supplements in adult volunteers. (Böckmann KA, 2022)PubMed
- Choline — Health Professional Fact SheetNIH ODS
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