Compound · alpha-gpc
T1Nootropic

Alpha-GPC (L-Alpha Glycerylphosphorylcholine)

Bioavailable choline source that crosses the blood-brain barrier efficiently. Serves as a direct precursor to acetylcholine synthesis via choline acetyltransferase. Also acts as a phosphatidylcholine precursor, supporting neuronal membrane integrity. Secondary growth hormone potentiation observed at higher doses through cholinergic stimulation of hypothalamic GHRH release.

Half-life
4-6 hours
Bioavailability
~88% (oral)
Route
oral
Evidence tier
T1 — Multiple RCTs
Optimization pillars
cellular-health
References
3 peer-reviewed
Dose ranges

Three tiers ordered by aggressiveness. Tier chips on every OPTIMIZE intervention let you filter the catalog by your evidence tolerance.

conservative
300 mg/day
Racetam support / choline maintenance
moderate
300–600 mg/day
Cognitive enhancement
aggressive
600–1200 mg/day
GH potentiation / clinical cognitive decline
Monitoring
  • homocysteine
  • alt
  • ast
  • lipid-panel
Contraindications
  • tmao-elevated
  • history-of-atherosclerotic-events
References
  • PMID:14669926Cognitive improvement in mild to moderate Alzheimer dementia after treatment with the acetylcholine precursor choline alphoscerateClin Ther, 2003
  • PMID:22673596The effect of alpha-GPC on growth hormone secretionJ Int Soc Sports Nutr, 2012
  • PMID:28927685The relation of dietary choline to cognitive performance and white-matter hyperintensityAm J Clin Nutr, 2011
Notes

Alpha-GPC is the choline source that actually matters. Choline bitartrate is 41% choline by weight and barely crosses the blood-brain barrier. Alpha-GPC is 40% choline by weight and crosses it readily. The racetam community figured this out decades ago. If you are running any racetam without adequate choline, you are depleting acetylcholine reserves and wondering why you have a headache. The TMAO concern at chronic high doses is real and worth monitoring. Homocysteine panels every 6 months.

This is not medical advice

Discuss with a licensed clinician before starting, stopping, or changing any compound. This page documents what the research literature describes — it is not a prescription.

See Alpha-GPC (L-Alpha Glycerylphosphorylcholine) in a protocol matched to you

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