What is Acetyl L-Carnitine (Acetyl L-Carnitine (ALCAR))?
Acetyl L-Carnitine (ALCAR) is an acetylated derivative of L-carnitine. Like L-carnitine, it is involved in the transport of long-chain fatty acids into the mitochondria; additionally, the acetyl group can contribute to the cellular acetyl-CoA pool. Due to its lipophilic nature, it has been particularly studied in nerve tissue and fatigue research.
- CAS number: 5080-50-2
- Molecular formula: C₉H₁₈ClNO₄
What is Acetyl L-Carnitine Used For? Why is it Used?
Thanks to its lipophilic structure, ALCAR is the carnitine form preferred in fatigue/cognitive research targeting nerve tissue. In sports products, it is positioned with the concept of fatigue support. It should be noted that claims have been rejected by EFSA; communication should be honest, focusing on mechanisms and tolerability.
Usage as a Sports Nutrition Product
The following information is based on sports nutrition research (ISSN position stands, randomized controlled trials, and meta-analyses); the level of evidence is clearly specified for each item.
- Mental and physical fatigue: There are RCTs reporting improvements in physical fatigue, mental fatigue, and fatigue severity with 2 g/day of levocarnitine/ALCAR in elderly populations and those with fatigue complaints (e.g., centenarian RCT, PMID 18065594). The effect on performance in healthy athletes has not been directly demonstrated; the level of evidence is moderate and population-specific.
- Cognitive support / focus: Evidence for ALCAR providing significant cognitive benefits in individuals without cognitive impairment is weak; the effect is more pronounced in mild cognitive impairment/early stages and is of small magnitude. Claims of 'focus' in athletes are honestly supported by weak evidence.
- Logic of fat metabolism: The role of the L-carnitine family in fatty acid transport is physiologically established; however, it has not been clinically proven that ALCAR increases fat burning or endurance in healthy athletes. Usage is mechanism-based, not a performance promise.
- Dosage and evidence summary: 1-2 g/day is a practical sports dose. Level of evidence: moderate for fatigue (clinical populations), low/insufficient for healthy athlete performance. Exaggerated ergogenic claims should be avoided.
Forms and Differences
Acetyl L-Carnitine is offered in different forms; form selection is made based on bioavailability, stability, and intended use:
- Acetyl L-Carnitine HCl (powder/capsule): The most common commercial form. An acetyl group is added to the L-carnitine base; it is stable as a hydrochloride salt and water-soluble. It is standard in sports nutrition and neuro-support supplements.
- Brain/neuro-focused form: The acetyl group makes the molecule more lipophilic (fat-soluble); it is suggested that it crosses cell membranes and the blood-brain barrier more easily than L-carnitine base. Therefore, it is the preferred form in cognitive/fatigue studies.
Usage in Dietary Supplements
- Typical daily dose: The range commonly used in clinical studies is 1-3 g/day (usually in divided doses). 2 g/day has been frequently used in studies on elderly fatigue and cognition.
- Timing: Can be taken on an empty or full stomach. For those reporting stimulant-like effects, it is recommended to avoid late evening intake. It is generally divided into morning and noon doses.
Usage in the Food Industry
- Clinical/medical nutrition: It can be used as a carnitine source in enteral and clinical nutrition formulations, particularly to maintain carnitine status in patients receiving long-term nutritional support.
Effects on Health
- Fatty acid transport (mitochondrial): Carnitine transports long-chain fatty acids across the inner mitochondrial membrane via the carnitine shuttle; these fatty acids are converted to energy via beta-oxidation. This is a well-established fundamental physiological role (NIH ODS).
- Acetyl group and energy buffer: The acetyl group of ALCAR may contribute to the cellular acetyl-CoA pool; it is being researched for its potential support of energy metabolism and neurotransmitter processes in nerve tissue (not yet proven at the level of health claims).
Status of Health Claims (EFSA) — Transparent Information
EFSA has REJECTED claims regarding 'faster recovery from post-exercise muscle fatigue', 'muscle tissue repair', 'increase in endurance capacity', and 'contribution to normal lipid metabolism' related to L-carnitine (EFSA Journal 2011;9(6):2212 and 2018;16(1):5137). There are no approved sports/fat-burning health claims for carnitine forms including ALCAR. Usage is based on established physiology and population-specific RCT data; performance claims cannot be made in marketing.
Usage Limits and Safety
- Typical usage dose: 1-3 g/day (typical 2 g/day in fatigue/cognitive RCTs)
- Upper Intake Level (UL): No official UL has been established; carnitine forms are generally well tolerated at ~2 g/day (up to ~4 g/day total) (NIH ODS).
- Turkish legislation (Sports Foods / TETGK): In Turkey, carnitine falls under amino acid/compound products within the scope of the Turkish Food Codex Sports Foods Regulation (2003/42) and the Dietary Supplements Regulation. I could not confirm a specific numerical upper limit for ALCAR in the regulation — NO NUMBER HAS BEEN FABRICATED; current Ministry legislation should be followed.
Nausea, abdominal cramps, diarrhea, and fishy body odor may occur at high doses. There is a discussion regarding cardiovascular issues due to TMAO increase from gut microbiota in the L-carnitine family.
Technical Specifications
| Parameter | Value |
|---|---|
| Moisture | ≤5.0 % |
| Total Heavy Metals | ≤10 ppm |
| E. Coli | Negative in 10 g |
| Salmonella | Negative in 25 g |
| Solubility | Water Soluble |
Scientific Studies
The following independent researches relate to the sports performance, bioavailability, and effects of this compound (study types are specified):
- PubMed 18065594 — L-carnitine treatment reduces physical and mental fatigue severity and increases cognitive function in centenarians: randomized controlled clinical study
- PubMed 28349514 — L-carnitine for cognitive enhancement in individuals without cognitive impairment
Technical Documents and Supply — Asuka Kimya
You can contact Asuka Kimya for SDS, TDS, CoA, and supply conditions for Acetyl L-Carnitine (ALCAR).
References
- ods.od.nih.gov
- efsa.onlinelibrary.wiley.com
- efsa.onlinelibrary.wiley.com
- pubmed.ncbi.nlm.nih.gov
- pubmed.ncbi.nlm.nih.gov
The usage, sports nutrition, and health information on this page have been compiled from official legislation/institution sources (EFSA, NIH ODS, ISSN, Turkish Food Codex Sports Foods / Dietary Supplements Regulation) and independent scientific publications (PubMed). The product is a food supplement/sports nutrition raw material; it does not aim to diagnose or treat diseases.