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Alpha-GPC and attention: grade C

Limited evidence. Direction: No effect.

Evidence maturity: EmergingIndustry-fundedShort-term only

Educational guidance, not medical advice

Why this grade

Rubric condition met: C: one small RCT in healthy adults positive on one of three attention tests; a second small RCT found no effect on psychomotor vigilance

A supplier-funded, retrospectively registered crossover trial in 20 resistance-trained men found larger improvements in Stroop total score after 630 mg (d = 0.61) and 315 mg (d = 0.48) than placebo, but no differences on the Flanker or N-Back tests. A supplier-funded 7-day trial (n=48) found no group differences on the psychomotor vigilance task. Taken together, the two trials do not show a consistent effect on attention. Trials in clinical populations are excluded from this grade.

How sure are we?

Evidence maturity: Emerging Small RCTs in healthy adults, all industry-funded; the positive Stroop result is post-hoc under the registry check.

Tested as: Alpha-GPC (L-alpha-glycerylphosphorylcholine)

Who paid for the studies
All industry-funded
Risk of bias
Some concerns
Trial registry check
Registered after the trial started. NCT06690619 was first submitted November 12, 2024, after the trial completed on June 11, 2024; its N-Back primary was null, so the Stroop result counts as post-hoc.
Outcome measured
A test score, rating scale or performance measure
Who was studied
Matched
Doses used in studies
315 and 630 mg single doses
  • Could rise: Would move to C benefit with an independent preregistered RCT with a single prespecified attention primary, positive.
  • Could fall: Would move to N with two adequately sized independent RCTs null.

Science is provisional. This grade reflects the evidence we found as of . Next review: .

Maturity sits beside each grade. The grade says what the evidence shows; maturity says how much of it there is and how well it is confirmed.

Established
many trials from several independent teams, including at least one registered in advance
Emerging
two or more trials, or one large registered trial, not yet independently confirmed
Early signal
one trial, small pilots, or results only on secondary outcomes
Mechanistic only
lab, animal or biomarker data, or uncontrolled reports; no controlled human results
Traditional use only
a traditional-use monograph and nothing else

How we grade evidence

Studies this grade rests on

EffectMixedNo effectSize shows participants (n)201520202025RCTCrossover RCTMarcus 2017, 2017: RCT, n = 48, result not recordedKerksick 2024, 2024: crossover RCT, n = 20, result not recorded
each study this grade rests on, by publication year and design. Solid: effect versus the comparator; half-filled: mixed; hollow: no effect; dashed: result not recorded yet. Larger marks had more participants.
Show the numbers
StudyYearDesignParticipantsResult
Marcus 20172017RCT48result not recorded
Kerksick 20242024crossover RCT20result not recorded

Evaluation of the effects of two doses of alpha glycerylphosphorylcholine on physical and psychomotor performance.

Marcus L, Soileau J, Judge LW. Evaluation of the effects of two doses of alpha glycerylphosphorylcholine on physical and psychomotor performance J Int Soc Sports Nutr, 2017. PMID 29042830

Result not recorded
Design
Randomized, placebo-controlled parallel-group trial (4 arms incl. caffeine), 7 days
Sample
n = 48
Population
Healthy college-aged men
Funding
ChemiNutra (ingredient supplier; Crossref funder list)

Acute Alpha-Glycerylphosphorylcholine Supplementation Enhances Cognitive Performance in Healthy Men.

Kerksick CM. Acute Alpha-Glycerylphosphorylcholine Supplementation Enhances Cognitive Performance in Healthy Men Nutrients, 2024. PMID 39683633

Result not recorded
Design
Randomized, double-blind, placebo-controlled crossover trial (acute single doses)
Sample
n = 20
Population
Resistance-trained healthy men
Funding
NNB Nutrition (ingredient supplier) restricted grant

Search and history

Search (): (alpha-GPC[tiab] OR glycerylphosphorylcholine[tiab] OR "choline alfoscerate"[tiab]) AND (attention[tiab] OR cognitive[tiab] OR cognition[tiab] OR memory[tiab]) AND randomized controlled trial[pt]

  • Graded C (awaiting approval)
  • C to C (awaiting approval)
  • C to C (approved): Editor sign-off November 13, 2026: grade matches the editor-approved final page
  • C to C (approved) (maturity: emerging): Maturity, bias summary and re-check date added