Glycerophosphocholine (GPC)

Tier 3 — weak evidence · Cognition · Stroke recovery · Growth hormone

A highly absorbable choline source that readily crosses the blood-brain barrier. A 2024 review found it improves cognitive function in dementia and aids stroke recovery. One trial also showed 600 mg acutely boosted growth hormone release. Generally well tolerated with few side effects. Provides the choline most people lack in their diet.

Dose: 300–600 mg/day for cognition; 600 mg pre-exercise for GH (single study)