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Choline (Alpha-GPC / CDP-choline)

Citicoline / Alpha GPC / Alpha-GPC · Brain

ModerateSeveral human trials, smaller or less consistent.

Acetylcholine precursors — the standard "stack base" nootropics, with modest real evidence and one cardiovascular question mark.

What the evidence says

Citicoline has a respectable set of small human trials showing attention and memory signals, mostly in older or impaired groups; Alpha-GPC adds a few power-output studies in athletes. Healthy-young-adult benefits are subtler than the nootropic forums imply.

What studies used

Cognition trials used Alpha-GPC 300–600 mg or citicoline 250–500 mg per day. Published studies had not established a timing dependence.

Reported from published studies and product labelling — a record of what was used in research, not a recommendation. What is right for you is a conversation with a clinician.

Watch out for

  • A 2021 Korean cohort study (age 50+, prescription-exposure data, observational) associated Alpha-GPC use with higher stroke incidence — not a randomized finding and not about ordinary supplement use, but unresolved
  • Headache or low mood at high doses is the community's consistent overshoot report

Evidence base

S1,316 research papers
established literature

Large human evidence base: several phase 3 or 4 trial reports, plus multiple meta-analyses or systematic reviews.

This letter measures how much human research exists, not whether it works for you — the tier above (Moderate) is the read on quality.

Research (12)

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