Meta Information
ID:alcar
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:
/class/anticoagulants-antiplatelets
Target name:
Anticoagulants and Antiplatelets (e.g., Warfarin)
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Acetyl-L-Carnitine may enhance the effects of anticoagulant and antiplatelet drugs, significantly increasing the risk of bleeding and bruising.
Actionable advice:
This should not be taken with anticoagulant or antiplatelet medications unless under strict medical supervision.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
For current labeling information, please visit https://www.fda.gov/drugsatfda
Clinical Considerations
Monitor breastfeeding infants for bruising or bleeding.
Label source:
Action type:
avoid
Target id:
/condition/renal-impairment
Target name:
Severe Renal Impairment / Dialysis
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
In severe kidney disease, metabolites of carnitine (like TMAO) can accumulate to toxic levels, a condition known as 'fishy odor syndrome' and potentially contributing to atherosclerosis.
Actionable advice:
This should not be used in severe kidney disease or during dialysis.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Trimethylamine N-oxide (TMAO) is a gut microbiota-derived metabolite of dietary phosphatidylcholine and carnitine. Mechanistically, TMAO raises urine albumin-to-creatinine ratio (UACR).
Label source:
PubMed: Associations of Plasma Trimethylamine N -Oxide-Related Metabolites with the Development and Progression of Albuminuria : The Multiethnic Study of Atherosclerosis. (PMID 40996814)
Action type:
avoid
Target id:
/condition/thyroid-disorders
Target name:
Thyroid Disorders (especially Hypothyroidism)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
L-carnitine can inhibit the action of thyroid hormones at the cellular level, potentially worsening symptoms of hypothyroidism or reducing the effectiveness of thyroid medication.
Actionable advice:
It is important to consult a physician before use for those with any thyroid condition, especially hypothyroidism.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Old studies in animals and unblinded studies in a few hyperthyroid patients suggested that L -carnitine is a periferal antagonist of thyroid hormone action at least in some tissues.
Label source:
PubMed: Usefulness of L-carnitine, a naturally occurring peripheral antagonist of thyroid hormone action, in iatrogenic hyperthyroidism: a randomized, double-blind, placebo-controlled clinical trial. (PMID 11502782)
Action type:
informational_none
Target id:
/condition/seizure-disorder
Target name:
Seizure Disorder / Epilepsy
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
There have been reports of increased seizure frequency in individuals with a pre-existing seizure disorder who take L-carnitine.
Actionable advice:
Use is best avoided with a history of seizures unless approved by a neurologist.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Intracerebral injection of L-acetylcarnitine in rats induced interictal and ictal epileptic phenomena with immediate onset, lasting up to 4 h.
Label source:
PubMed: Neuropharmacology (1984)
Source url:
Exact phrase from label:
L-carnitine induced only ictal discharges with a latency of 40-90 min.
Label source:
PubMed: Neuropharmacology (1984)
Source url:
Exact phrase from label:
even though ALCAR did not delay the kindling process, it did show some promising ameliorative effects, worthy of further investigation.
Label source:
PubMed: Neurochemistry international (2012)
Action type:
avoid
Target id:
/condition/bipolar-disorder
Target name:
Bipolar Disorder
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Case reports suggest that L-carnitine supplementation may trigger symptoms of mania or hypomania in individuals with bipolar disorder.
Actionable advice:
Use is best avoided with bipolar disorder, as it may worsen symptoms.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
This bioenergetic-purinergic axis underlies mood cycling: mania reflecting bioenergetic upregulation with purinergic hyperactivity, and depression representing bioenergetic downregulation with purinergic hypoactivity. Biomarkers such as uric acid, xanthine dehydrogenase and adenosine deaminase activity, phosphocreatine, ATP levels, and oxidative stress indices demonstrate phase-dependent alterations and hold promise for diagnosis, prognosis, and treatment monitoring. Therapeutic opportunities extend beyond conventional mood stabilizers to include xanthine oxidase inhibitors (e.g., allopurinol), P2 × 7 antagonists, adenosine modulators, and mitochondrial-supportive agents (e.g., creatine, carnitine, CoQ10, N-acetylcysteine).
Label source:
PubMed: Purinergic signaling and energetic metabolism in bipolar disorder: From pathophysiology to precision therapeutics. (PMID 41468703)
Action type:
avoid
Target id:
/condition/pregnancy
Target name:
Pregnancy
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
The safety of Acetyl-L-Carnitine supplementation during pregnancy has not been established through rigorous clinical trials.
Actionable advice:
Use is best avoided during pregnancy unless specifically prescribed by a healthcare provider.
Validation status:
anecdotal
Evidence tier:
tier_d
Evidence basis:
anecdotal_summary
Evidence anchors:
Exact phrase from label:
It is not known if or how acetyl-L-carnitine could affect pregnancy or harm a fetus.
Label source:
Anecdotal: WebMD
Action type:
avoid
Target id:
/condition/lactation
Target name:
Breastfeeding (Lactation)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
It is unknown if supplemental Acetyl-L-Carnitine is excreted in breast milk and what its effects on a nursing infant might be.
Actionable advice:
Use should be 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:
It is not known if acetyl-L-carnitine passes into breast milk, but carnitine passes into breast milk.
Label source:
Anecdotal: WebMD
Action type:
avoid
Target id:
/dietary/meal
Target name:
Any Caloric Meal
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
1
Hours after target:
2
Description:
Food, especially meals containing protein, can compete with Acetyl-L-Carnitine for absorption in the small intestine, reducing its bioavailability.
Actionable advice:
It is best taken on an empty stomach, at least 1 hour before or 2 hours after a meal.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Dietary L-carnitine is absorbed by active and passive transfer across enterocyte membranes. Bioavailability of dietary L-carnitine is 54-87% and is dependent on the amount of L-carnitine in the meal.
Label source:
PubMed: Annals of the New York Academy of Sciences (2004)
Source url:
Exact phrase from label:
Both carnitine and acetylcarnitine exhibited low intestinal absorption and renal reabsorption.
Label source:
PubMed: Molecular nutrition & food research (2025)
Source url:
Exact phrase from label:
These results indicate that oral carnitine is 54 to 87% bioavailable from normal Western diets; the percentage of intake absorbed is related to the quantity ingested.
Label source:
PubMed: The Journal of nutrition (1991)
Action type:
separate
Target id:
/circadian/sleep
Target name:
Going to Sleep
Severity:
moderate
Interaction type:
adverse
Nature:
temporal
Temporal spacing:
Hours before target:
6
Hours after target:
null
Description:
Acetyl-L-Carnitine can have a stimulating effect on the brain and central nervous system, which may interfere with sleep onset and quality for some individuals.
Actionable advice:
The last dose is best taken at least 6 hours before the intended bedtime.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Supplementation with acetyl-L-carnitine (ALC), an acetyl group donor, ameliorates motor and cognitive deficits in other disease models through a variety of mechanisms including altering patterns of histone acetylation resulting in changes in gene expression, and stimulating biosynthetic pathways such as acetylcholine.
Label source:
PubMed: Acetyl-L-carnitine improves behavior and dendritic morphology in a mouse model of Rett syndrome. (PMID 23227269)
Action type:
separate
Target id:
/circadian/wake
Target name:
Waking Up
Severity:
moderate
Interaction type:
synergistic
Nature:
temporal
Temporal spacing:
Hours before target:
null
Hours after target:
1
Description:
Taking ALCAR in the morning aligns with the body's natural active cycle and can leverage its potential benefits for mental and physical energy.
Actionable advice:
The first dose is best taken within an hour of waking for potential energizing effects.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
The intracerebroventricular (i.c.v.) injection of acetyl-L-carnitine in the freely moving cat, during a spontaneous synchronous phase of sleep, induced the animal's arousal and a delay of the subsequent appearance of desynchronized sleep.
Label source:
PubMed: International journal of clinical pharmacology research (1990)
Source url:
Exact phrase from label:
Significant interactions were observed for perceived alertness, concentration, energy, and focus, with increases in TX.
Label source:
PubMed: Cureus (2024)
Source url:
Exact phrase from label:
No significant difference was found between the levels in the morning and in the afternoon, although a higher carnitinaemia was shown in the waking hours when the energy demands were higher.
Label source:
PubMed: Drugs under experimental and clinical research (1989)
Action type:
informational_none
Target id:
/intervention/alpha-lipoic-acid
Target name:
Alpha-Lipoic Acid (ALA)
Severity:
moderate
Interaction type:
synergistic
Nature:
temporal
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
ALCAR and ALA work together to support mitochondrial function, with ALCAR aiding fatty acid transport and ALA acting as a key cofactor in mitochondrial energy production.
Actionable advice:
It is best taken at the same time as Alpha-Lipoic Acid to support mitochondrial health.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Treatments with the combination of LA and ALC at concentrations of 0.1, 1 and 10 micromol/l for 24 h significantly increased mitochondrial mass, expression of mitochondrial DNA, mitochondrial complexes, oxygen consumption and fatty acid oxidation in 3T3L1 adipocytes.
Label source:
PubMed: Diabetologia (2008)
Source url:
Exact phrase from label:
We and others have shown that feeding old rats ALCAR reverses the age-related decline in carnitine levels and improves mitochondrial beta-oxidation in a number of tissues studied. However, ALCAR supplementation does not appear to reverse the age-related decline in cardiac antioxidant status and thus may not substantially alter indices of oxidative stress.
Label source:
PubMed: Annals of the New York Academy of Sciences (2002)
Action type:
informational_none
Target id:
/intervention/coenzyme-q10
Target name:
Coenzyme Q10 (CoQ10)
Severity:
moderate
Interaction type:
synergistic
Nature:
temporal
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Both ALCAR and CoQ10 are crucial for the mitochondrial electron transport chain, and taking them together provides comprehensive support for cellular energy (ATP) production.
Actionable advice:
It is best taken at the same time as CoQ10 for enhanced cellular energy support.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Exact phrase from label:
ALA and CoQ10—or a combination of both—in people with ARD... the proposed MNs may be the safest triad for mild mitochondrial effects. Lipoic acid can directly scavenge superoxide and improve mitochondrial function, CoQ10 is an important endogenous lipid-soluble antioxidant, and CARN reduces OS in many biological systems
Label source:
Primary literature: https://pmc.ncbi.nlm.nih.gov/articles/PMC7582285/
Action type:
informational_none
Target id:
/class/anticonvulsants
Target name:
Enzyme-Inducing Anticonvulsant Medications
Severity:
moderate
Interaction type:
synergistic
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Certain anticonvulsants (e.g., valproic acid, phenytoin) can deplete the body's carnitine stores, and supplementation may be necessary to counteract this deficiency.
Actionable advice:
If taking these medications long-term, discuss carnitine supplementation with your doctor.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
John's wortb, sucralfate, theophylline Drugs that may either increase or decrease phenytoin serum levels Antiepileptic drugs Phenobarbital, valproate sodiumc, valproic acidc a Antacids may affect absorption of phenytoin.
Label source:
Action type:
informational_none
Target id:
/intervention/exercise
Target name:
Exercise
Severity:
minor
Interaction type:
synergistic
Nature:
temporal
Temporal spacing:
Hours before target:
1
Hours after target:
null
Description:
ALCAR facilitates the transport of long-chain fatty acids into mitochondria to be used for energy, which may be beneficial when taken before physical activity.
Actionable advice:
Consider taking a dose about 30-60 minutes before exercise to support energy metabolism.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
This molecule has important physiological roles, including its involvement in the beta-oxidation of fatty acids by facilitating the transport of long-chain fatty acids across the mitochondrial inner membrane as acylcarnitine esters.
Label source:
PubMed: [Physiological functions of carnitine and carnitine transporters in the central nervous system]. (PMID 18646596)
Action type:
informational_none
Target id:
/class/amino-acids
Target name:
High-Dose Amino Acid Supplements
Severity:
minor
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
0.5
Hours after target:
0.5
Description:
Theoretically, high doses of other large neutral amino acids taken at the same time could compete with ALCAR for intestinal absorption transporters.
Actionable advice:
ALCAR and other high-dose amino acid supplements are best separated by at least 30 minutes.
Validation status:
validated_via_expert_review
Evidence tier:
tier_c
Evidence basis:
expert_review_verbatim
Evidence anchors:
Exact phrase from label:
ATB0,+ is a very poor transporter of acetyl-l-carnitine
Label source:
Expert review: OCTN2 organic cation/carnitine transporter is pharmacologically distinct from LAT1/B0AT1 large neutral amino acid transporters; ATB0+ is the relevant intestinal overlap but has low affinity for ALCAR vs. L-carnitine
Action type:
separate