Acetyl-L-Carnitine
Research reviewed: Up until 03/2026
Acetyl-L-Carnitine is a dietary supplement with 25 published peer-reviewed studies involving 2,041 participants, researched for Cognitive Function & Memory, Fatigue & Mood, Neuropathy & Nerve Function and 3 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Cognitive Function & Memory
ModerateFatigue & Mood
ModerateNeuropathy & Nerve Function
ModeratePhysical Performance & Aging
StrongClinical trials
ModerateSystematic reviews
WeakResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Cognitive Function & Memory
To evaluate ALC effects on cognitive decline in Alzheimer's disease
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate ALC effects on cognitive decline in Alzheimer's disease
Dose
2500 mg/day
Participants
431 Alzheimer's disease patients
Duration
12 months
Results
Slower rate of cognitive decline on ADAS-cog (p=0.04). Particularly significant in patients under age 62.
How They Measured It
ADAS-cog, MMSE, Clinical Global Impression
To evaluate the efficacy of ALC in MCI and Alzheimer's
Study Type
Systematic review and meta-analysis
Purpose
To evaluate the efficacy of ALC in MCI and Alzheimer's
Dose
1500-3000 mg/day
Participants
Meta-analysis of 21 RCTs
Duration
3-12 months
Results
Significant benefit vs placebo. Effect sizes 0.20-0.35. Greatest benefits in attention, memory and psychomotor performance.
How They Measured It
ADAS-cog, MMSE across 21 RCTs
To evaluate ALC in age-associated memory impairment
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate ALC in age-associated memory impairment
Dose
1500 mg/day
Participants
130 elderly patients with mild cognitive impairment
Duration
90 days
Results
Significant improvements in attention, memory and psychomotor speed vs placebo. MMSE scores improved by 2.4 points vs 0.8 in placebo (p<0.01).
How They Measured It
Selective Reminding Test, MMSE, neuropsychological battery
Fatigue & Mood
To assess ALC effects on fatigue and mood in cancer patients
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess ALC effects on fatigue and mood in cancer patients
Dose
2000 mg/day
Participants
72 cancer patients with chemotherapy-related fatigue
Duration
8 weeks
Results
Significant reduction in fatigue scores (p=0.001) and improvement in depression symptoms. Quality of life improved vs placebo.
How They Measured It
Brief Fatigue Inventory, HADS, FACT-G
To evaluate ALC as treatment for depression in elderly
Study Type
Randomised, double-blind, controlled
Purpose
To evaluate ALC as treatment for depression in elderly
Dose
3000 mg/day
Participants
60 elderly depressed patients
Duration
12 weeks
Results
HAM-D scores improved by 42% vs 18% in control (p<0.01). Cognitive function also improved.
How They Measured It
Hamilton Depression Scale, Geriatric Depression Scale
Neuropathy & Nerve Function
To evaluate ALC in diabetic peripheral neuropathy
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate ALC in diabetic peripheral neuropathy
Dose
1000 mg/day intramuscular
Participants
333 patients with diabetic neuropathy
Duration
12 months
Results
Significant reduction in pain scores and improvement in nerve conduction velocity. Nerve regeneration markers improved at 12 months.
How They Measured It
VAS pain, nerve conduction velocity, sural nerve biopsy
To review the evidence for ALC in painful neuropathies
Study Type
Systematic review
Purpose
To review the evidence for ALC in painful neuropathies
Dose
500-3000 mg/day
Participants
Meta-analysis of 14 RCTs
Duration
6-12 months
Results
ALC reduced neuropathic pain significantly vs placebo (SMD -0.73). Improvements in nerve regeneration markers noted.
How They Measured It
Pain scales, nerve conduction, quality of life
Physical Performance & Aging
To assess ALC on physical and mental fatigue in elderly
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess ALC on physical and mental fatigue in elderly
Dose
2000 mg/day
Participants
96 elderly patients with fatigue
Duration
6 months
Results
Significant improvement in physical function, cognitive function, and fatigue. Muscle mass and grip strength improved vs placebo.
How They Measured It
Fatigue questionnaires, cognitive tests, physical performance
To assess ALC effects on male fertility in infertile men
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess ALC effects on male fertility in infertile men
Dose
3000 mg/day L-carnitine + 1000 mg/day ALC
Participants
86 infertile men with low sperm motility
Duration
6 months
Results
Significant improvement in sperm motility (p<0.001). Spontaneous pregnancy rate 34% vs 8% in placebo.
How They Measured It
Sperm motility, morphology, count
To assess ALC on insulin sensitivity and metabolic parameters in type 2 diabetes
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess ALC on insulin sensitivity and metabolic parameters in type 2 diabetes
Dose
2000 mg/day
Participants
67 type 2 diabetes patients
Duration
12 weeks
Results
Significant improvement in insulin sensitivity (p=0.03), HbA1c reduced by 0.5%, triglycerides improved vs placebo.
How They Measured It
Insulin sensitivity index, HbA1c, lipid profile
Clinical trials
To investigate the effects of Acetyl-L-Carnitine in dietary lipid quantity and quality modulate the postprandial metabolomic profile in patients with metabolic syndrome.
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Acetyl-L-Carnitine in dietary lipid quantity and quality modulate the postprandial metabolomic profile in patients with metabolic syndrome.
Dose
Acetyl-L-Carnitine (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
The literature on the postprandial metabolic changes in individuals with Metabolic Syndrome (MetS) remains limited, despite the fact that postprandial states represent the most common physiological condition in Western societies.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in a prospective randomized controlled trial of antioxidants in human ivf and embryo culture media.
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Acetyl-L-Carnitine in a prospective randomized controlled trial of antioxidants in human ivf and embryo culture media.
Dose
Acetyl-L-Carnitine (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
Does the addition of three antioxidants to culture media during gamete collection, insemination, and embryo culture increase the clinical pregnancy rate from fresh blastocyst transfers?
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in d-bhb supplementation before moderate-intensity exercise suppresses lipolysis and selectively blunts exercise-induced long-chain acylcarnitine increas
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Acetyl-L-Carnitine in d-bhb supplementation before moderate-intensity exercise suppresses lipolysis and selectively blunts exercise-induced long-chain acylcarnitine increas
Dose
Acetyl-L-Carnitine (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
, our results provide a strong rationale for future studies aimed toward defining the optimal multiple-dose regimen of D-BHB per day that might improve exercise tolerance and understanding the long-term impact of treatment in LC-FAOD subjects.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in antioxidant treatment for oligoasthenoteratozoospermia and varicocele: a dbpc trial to evaluate the impact of age and body mass index.
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Acetyl-L-Carnitine in antioxidant treatment for oligoasthenoteratozoospermia and varicocele: a dbpc trial to evaluate the impact of age and body mass index.
Dose
Acetyl-L-Carnitine (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
, antioxidant supplementation may be beneficial for infertile patients and has a more positive effect on younger patients with a normal weight.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in combined rehabilitation with alpha lipoic acid, acetyl-l-carnitine, resveratrol, and cholecalciferolin discogenic sciatica in young people: a randomiz
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Acetyl-L-Carnitine in combined rehabilitation with alpha lipoic acid, acetyl-l-carnitine, resveratrol, and cholecalciferolin discogenic sciatica in young people: a randomiz
Dose
3 g
Participants
128 participants
Duration
30 days
Results
: The combined treatment of rehabilitation and supplements with anti-inflammatory, pain-relieving, and antioxidant action is effective in the treatment of sciatica and can be useful in improving postural stability.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in l-carnitine and alpha-lipoic acid fail to improve anaerobic and aerobic performance in trained cyclists despite a reduction in blood lactate concentra
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Acetyl-L-Carnitine in l-carnitine and alpha-lipoic acid fail to improve anaerobic and aerobic performance in trained cyclists despite a reduction in blood lactate concentra
Dose
1200 mg/day
Participants
41 participants
Duration
Duration not specified
Results
: Four weeks of Acetyl-l-Carnitine and ALA supplementation did not enhance aerobic or anaerobic performance in trained cyclists, despite reducing blood lactate after high-intensity exercise, suggesting no ergogenic benefits.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in effects of dietary rumen-protected choline supplementation to periparturient dairy cattle on inflammation, metabolism, and performance during an intra
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Acetyl-L-Carnitine in effects of dietary rumen-protected choline supplementation to periparturient dairy cattle on inflammation, metabolism, and performance during an intra
Dose
45 g
Participants
18 participants
Duration
Duration not specified
Results
of dietary RPC supplementation on milk yield could be mediated through metabolic pathways and are unlikely to be related to the resolution of inflammation in periparturient dairy cattle. Lastly, dose responses to dietary RPC supplementation were not found for various economically important outcomes including milk yield, limiting the justification for feeding a greater dietary RPC dose in industry.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in clinical usefulness of nutraceutics with acetyl-l-carnitine, α-lipoic acid, phosphatidylserine, curcumin, c, e and b-group vitamins in patients awaiti
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Acetyl-L-Carnitine in clinical usefulness of nutraceutics with acetyl-l-carnitine, α-lipoic acid, phosphatidylserine, curcumin, c, e and b-group vitamins in patients awaiti
Dose
600 mg
Participants
Participants not specified
Duration
Duration not specified
Results
leading to nerve ischemia, endoneural edema, venous congestion, and subsequent metabolic alterations. Conservative treatments could be considered. The present study investigates the efficacy of a specific blend of a 600 mg dietary integrator composed of acetyl-L-carnitine, α-lipoic acid, phosphatidylserine, Curcumin, C, E and B1, B2, B6 and B12 vitamins in patients with mild to moderate CTS.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in randomized clinical trial for the optimization of dyslipidemia management in patients with end-stage renal disease undergoing in-hospital maintenance
Study Type
Clinical study
Purpose
To investigate the effects of Acetyl-L-Carnitine in randomized clinical trial for the optimization of dyslipidemia management in patients with end-stage renal disease undergoing in-hospital maintenance
Dose
500 mg
Participants
49 participants
Duration
23 weeks
Results
: Both oral and IV interventions effectively improved lipid profiles, and IV administration showed a more pronounced effect on LDL reduction, suggesting potentially greater efficacy of IV administration for LDL reduction.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in palmitoylethanolamide and acetyl-l-carnitine act synergistically with duloxetine and pregabalin in fibromyalgia: results of a randomised controlled st
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Acetyl-L-Carnitine in palmitoylethanolamide and acetyl-l-carnitine act synergistically with duloxetine and pregabalin in fibromyalgia: results of a randomised controlled st
Dose
Acetyl-L-Carnitine (dose not specified)
Participants
Participants not specified
Duration
24 weeks
Results
Fibromyalgia (FM) is characterised by a form of debilitating pain that is unresponsive to standard analgesics. The aim of this study was to evaluate the efficacy of supplementing ongoing pregabalin (PGB) and duloxetine (DLX) treatment with palmitoylethanolamide (PEA) and acetyl-L-carnitine (ALC) for 24 weeks in FM patients.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in comparative study of choline alfoscerate as a combination therapy with donepezil: a mixed double-blind randomized controlled and open-label observatio
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Acetyl-L-Carnitine in comparative study of choline alfoscerate as a combination therapy with donepezil: a mixed double-blind randomized controlled and open-label observatio
Dose
Acetyl-L-Carnitine (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
Choline alfoscerate (alpha-glycerylphosphorylcholine) is a phospholipid that includes choline, which increases the release of acetylcholine. The ASCOMALVA trial, a combination of donepezil and choline alfoscerate, slowed cognitive decline in Alzheimer disease. This study aims to replicate the effect by combining donepezil with other nootropics currently used in South Korea.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in metabolic predictors of cardiorespiratory fitness responsiveness to continuous endurance and high-intensity interval training programs: the times stud
Study Type
Clinical study
Purpose
To investigate the effects of Acetyl-L-Carnitine in metabolic predictors of cardiorespiratory fitness responsiveness to continuous endurance and high-intensity interval training programs: the times stud
Dose
Acetyl-L-Carnitine (dose not specified)
Participants
Participants not specified
Duration
8 weeks
Results
These results highlight the potential value of serum and intramuscular metabolites as biomarkers for the classification of CRF responsiveness previous to different aerobic training programs.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in low bioavailability and high tmao production: novel insights into acetylcarnitine and carnitine metabolism.
Study Type
Randomized, double-blind, placebo-controlled
Purpose
To investigate the effects of Acetyl-L-Carnitine in low bioavailability and high tmao production: novel insights into acetylcarnitine and carnitine metabolism.
Dose
Acetyl-L-Carnitine (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
ent was mostly eliminated in the form of carnitine. Approximately 90% of both supplements were metabolized to TMAO, reaching 50 µM in plasma-levels previously found to be associated with adverse health outcomes. Acetylcarnitine has significantly lower bioavailability than carnitine. The intake of both supplements resulted in substantial TMAO production, raising potential health concerns.
How They Measured It
See study for outcome measures
Systematic reviews
To investigate the effects of Acetyl-L-Carnitine in differential metabolites in osteoarthritis: a systematic review and meta-analysis.
Study Type
Systematic review and meta-analysis
Purpose
To investigate the effects of Acetyl-L-Carnitine in differential metabolites in osteoarthritis: a systematic review and meta-analysis.
Dose
Acetyl-L-Carnitine (dose not specified)
Participants
495 participants
Duration
Duration not specified
Results
The main differential metabolites between OA and healthy subjects were amino acids (AAs) and their derivatives, including tryptophan, lysine, leucine, proline, phenylalanine, glutamine, dimethylglycine, citrulline, asparagine, acetylcarnitine and creatinine (muscle metabolic products), which could be potential biomarkers for predicting OA.
How They Measured It
See study for outcome measures
To investigate the effects of Acetyl-L-Carnitine in the effect of acetyl-l-carnitine (alcar) on peripheral nerve regeneration in animal models: a systematic review.
Study Type
Systematic review and meta-analysis
Purpose
To investigate the effects of Acetyl-L-Carnitine in the effect of acetyl-l-carnitine (alcar) on peripheral nerve regeneration in animal models: a systematic review.
Dose
Acetyl-L-Carnitine (dose not specified)
Participants
Participants not specified
Duration
Duration not specified
Results
re still unclear. Further studies are mandatory to clarify the actual mechanisms of the neuroprotective activity of ALCAR. Based on the results of existing studies, ALCAR effectively increases the tolerance threshold of thermal and mechanical stimuli, reduces latency, and reduces apoptosis; finally, adjusting the dose and duration of administration may increase the dose and duration axon diameter.
How They Measured It
See study for outcome measures
Frequently Asked Questions
Common questions about Acetyl-L-Carnitine research
There are currently 25 peer-reviewed studies on Acetyl-L-Carnitine (Acetyl-L-Carnitine), involving 2,041 total participants. Research covers Cognitive Function & Memory, Fatigue & Mood, Neuropathy & Nerve Function and 3 more areas. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (21 human studies), and reported outcomes.
Acetyl-L-Carnitine has been researched for: Cognitive Function & Memory, Fatigue & Mood, Neuropathy & Nerve Function, Physical Performance & Aging, Clinical trials, Systematic reviews. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 21 out of 25 studies are human trials. Human trials carry more weight in our evidence scoring system.
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