Meta Information
ID:alpha-gpc
Name:
Schema Version:2.4_uniform_evidence_2026_06_18
Created
2026-05-21T22:30:00Z
Model
phase-a-upgrade-claude-sonnet-4.6
Interactions
Target id:
/biomarker/tmao
Target name:
Trimethylamine N-oxide (TMAO)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Alpha-GPC is metabolized by gut bacteria into TMA, which is then converted in the liver to TMAO, a metabolite linked in some studies to an increased risk of atherosclerosis and adverse cardiovascular events.
Actionable advice:
Long-term high-dose alpha-GPC may raise TMAO. If you have cardiovascular risk factors, check TMAO periodically and keep the dose modest; this is a low-certainty signal.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
growing evidence suggests that high intake of choline-containing compounds, including GPC, is linked with trimethylamine N-oxide (TMAO) production, a metabolite associated with atherosclerosis progression. However, there has been an inconsistency that is not commonly discussed, and thus, the adverse effect of TMAO remains debatable.
Label source:
Chen et al., Nutrients (2026), PMID 42196986. FLAG: the review itself calls the TMAO-cardiovascular-risk association 'debatable'/inconsistent - the major severity overstates current certainty; treat as a monitorable theoretical risk.
Action type:
monitor
Target id:
/class/anticholinergic-medications
Target name:
Anticholinergic Medications
Severity:
major
Interaction type:
diminishing
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Alpha-GPC increases acetylcholine levels, while anticholinergic drugs (e.g., scopolamine, diphenhydramine, certain antidepressants) work by blocking acetylcholine receptors, leading to opposing effects that may nullify the efficacy of either substance.
Actionable advice:
Alpha-GPC should not be taken with anticholinergic drugs, as they directly counteract each other's primary mechanism of action.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / class pharmacology (no single primary source quoted)
Exact phrase from label:
Pharmacodynamic inference: alpha-GPC is a cholinergic precursor that raises acetylcholine availability, so anticholinergic drugs (which block muscarinic transmission) act in functional opposition. Plausible PD antagonism; not a quantified or labeled interaction.
Label source:
Class inference
Action type:
avoid
Target id:
/condition/pregnancy
Target name:
Pregnancy
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
The safety of Alpha-GPC supplementation during pregnancy has not been established, and its effects on fetal development are unknown.
Actionable advice:
This should be strictly avoided during pregnancy due to a lack of safety data.
Validation status:
anecdotal
Evidence tier:
tier_d
Evidence basis:
anecdotal_summary
Evidence anchors:
Exact phrase from label:
It is not known if or how alpha-GPC could affect pregnancy or harm an unborn baby.
Label source:
Anecdotal: WebMD
Action type:
avoid
Target id:
/condition/lactation
Target name:
Breastfeeding (Lactation)
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
It is unknown if Alpha-GPC is excreted in breast milk or what its effects might be on a nursing infant.
Actionable advice:
This should be strictly avoided while breastfeeding due to a lack of safety data.
Validation status:
anecdotal
Evidence tier:
tier_d
Evidence basis:
anecdotal_summary
Evidence anchors:
Exact phrase from label:
Alpha-GPC contains choline, which passes into breast milk.
Label source:
Anecdotal: WebMD
Action type:
avoid
Target id:
/class/cholinesterase-inhibitors
Target name:
Acetylcholinesterase Inhibitors
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Combining Alpha-GPC (a choline precursor) with drugs that inhibit acetylcholine breakdown (e.g., donepezil, galantamine) can lead to an excessive buildup of acetylcholine, potentially causing cholinergic side effects like nausea, sweating, and slowed heart rate.
Actionable advice:
This combination is best used only under strict medical supervision, as dose adjustments may be necessary.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / class pharmacology (no single primary source quoted)
Exact phrase from label:
Pharmacodynamic inference: pairing a choline precursor (more ACh substrate) with a cholinesterase inhibitor (less ACh breakdown) can additively raise cholinergic tone and theoretically cholinergic side effects. Mechanistic, not studied as a combination.
Label source:
Class inference
Action type:
adjust_with_prescriber
Target id:
/intervention/huperzine-a
Target name:
Huperzine A
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Huperzine A is a natural acetylcholinesterase inhibitor. Combining it with Alpha-GPC can cause an excessive buildup of acetylcholine, increasing the risk of cholinergic side effects like headache, nausea, or dizziness.
Actionable advice:
Co-administration is best avoided, or used with extreme caution, starting with very low doses of both supplements.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Furthermore, HupA elevates ACh concentrations across multiple brain regions, concurrently modulating several monoamine neurotransmitters.
Label source:
PubMed: Predicting cerebral acetylcholine dynamics with huperzine A pharmacokinetics in blood via mPBPK-PD modeling. (PMID 41781122)
Action type:
avoid
Target id:
/condition/hypotension
Target name:
Hypotension (Low Blood Pressure)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Alpha-GPC may have a mild blood pressure-lowering effect due to its parasympathetic (cholinergic) activity. In individuals who already have low blood pressure, this could exacerbate symptoms like dizziness or fainting.
Actionable advice:
This is best used with caution, and it is a good idea to monitor blood pressure in those with a history of hypotension.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / class pharmacology (no single primary source quoted)
Exact phrase from label:
Mechanistic inference: alpha-GPC raises cholinergic (and some GABAergic) tone; a mild blood-pressure-lowering / dizziness effect in already-hypotensive individuals is a plausible extrapolation. FLAG: the cited review (PMID 40036805) documents cholinergic activity but does NOT report a blood-pressure effect - this is mechanistic, not demonstrated.
Label source:
Class inference
Action type:
monitor
Target id:
/intervention/exercise
Target name:
Exercise
Severity:
minor
Interaction type:
synergistic
Nature:
temporal
Temporal spacing:
Hours before target:
1.5
Hours after target:
0.5
Description:
Taking Alpha-GPC before exercise has been shown in some studies to augment peak force production and increase exercise-induced growth hormone secretion.
Actionable advice:
Alpha-GPC is generally best taken approximately 30-90 minutes before a workout for potential performance benefits.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
GPC has beneficial effects on such conditions and measures as ischemic/hypoxic conditions, ionizing radiation-induced damage, exercise performance, growth hormone release, and liver damage.
Label source:
Review, Nutrition Reviews (2025), PMID 40036805. Supports exercise-performance and GH-release effects of alpha-GPC.
Action type:
separate
Target id:
/class/racetams
Target name:
Racetam Nootropics
Severity:
minor
Interaction type:
synergistic
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Racetams (e.g., piracetam, aniracetam) are thought to increase acetylcholine receptor sensitivity or utilization. Alpha-GPC provides the raw material for acetylcholine, potentially enhancing the cognitive effects of both.
Actionable advice:
This is a common nootropic stack; consider starting with lower doses of each to assess tolerance and avoid headaches.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / class pharmacology (no single primary source quoted)
Exact phrase from label:
Pharmacodynamic inference: alpha-GPC is an acetylcholine precursor (confirmed in PMID 40036805); racetams are thought to increase cholinergic utilization, so co-use may be additive on cholinergic cognitive effects. Plausible, not tested as a combination.
Label source:
Class inference
Action type:
avoid
Target id:
/circadian/sleep
Target name:
Sleep
Severity:
minor
Interaction type:
adverse
Nature:
temporal
Temporal spacing:
Hours before target:
6
Hours after target:
null
Description:
Due to its role in producing acetylcholine, a neurotransmitter involved in arousal and wakefulness, Alpha-GPC may be mildly stimulating and could interfere with sleep onset in sensitive individuals.
Actionable advice:
Alpha-GPC is generally best taken more than 6 hours before intended bedtime.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
We also show that these neurons are inhibited by noradrenaline and acetylcholine, both of which are transmitters of wakefulness.
Label source:
PubMed: Nature (2000)
Source url:
Exact phrase from label:
The two major cholinergic cell groups of this core, one within the pontomesencephalic tegmentum that projects rostrally into the non-specific thalamo-cortical relay system and the other within the basal forebrain that receives input from the brainstem reticular formation and projects in turn as the ventral, extrathalamic relay upon the cerebral cortex, are critically involved in processes of cerebral activation that accompany the states of wakefulness and paradoxical sleep.
Label source:
PubMed: Progress in brain research (1993)
Source url:
Exact phrase from label:
Behavioral hyper-responsiveness which interferes with sleep onset, combined with reduced activity in brainstem cholinergic mechanisms involved in REM sleep generation may underlie daytime sleep-waking disturbances in NADE rats.
Label source:
PubMed: Brain research (1993)
Action type:
separate
Target id:
/intervention/choline
Target name:
Other Choline Supplements
Severity:
minor
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Combining multiple high-dose choline sources (e.g., citicoline, choline bitartrate) can increase the risk of cholinergic side effects like headaches, gastrointestinal distress, or a fishy body odor.
Actionable advice:
Only one primary choline source is generally best used at a time, or the total daily choline intake carefully calculated to stay within safe limits.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Exact phrase from label:
Muscarinic effects of ACh include the following:
Eye: Miosis and blurred vision
Gastrointestinal system: Nausea, vomiting, and diarrhea
Respiratory system: Decreased lung compliance, bronchoconstriction, and bronchorrhea
Secretory system: Increased secretions in the tracheobronchial and gastrointestinal systems
Cardiovascular system: Bradycardia
Genitourinary system: Increased urinary frequency and urgency
Label source:
PubMed/primary literature: https://www.ncbi.nlm.nih.gov/books/NBK482433/
Action type:
informational_none