Search social media for information on potentially beneficial supplements and you’ll read and hear a lot about Acetyl-L-Carnitine (ALCAR or ALC).
ALCAR is a trending topic as more people – from functional health experts, supplement manufacturers and health and fitness influencers – promote this supplement for its potential to help transport more fat into muscle cells to produce more energy, which burns more fat in the process.
All about Carnitine
The two most common forms of carnitine supplements available are L-Carnitine and ALCAR. Both are derived from carnitine, an amino acid that transports fatty acids into muscle cells where they are metabolised for energy within structures called mitochondria – the so-called metabolic powerhouses of our cells.
Our bodies naturally produce L-Carnitine in the liver and kidneys (it is produced from the amino acids lysine and methionine). Most people can produce sufficient carnitine through their diet by eating natural food sources.
And your body can convert L-Carnitine to ALCAR (and visa versa) through the function of certain enzymes to meet the metabolic needs of your cells.
Carnitine is also naturally present in various animal-derived foods, especially red meat. Other sources include poultry, fish, dairy and avocados. We can also boost carnitine levels in the body with supplements.
We store about 95%1 of total body carnitine in heart (cardiac) and skeletal muscle. We store most of the remaining amount in the liver and kidneys, with a small proportion (about 0.5%) circulating through the body.
The ALCAR effect
The benefits of an ALCAR supplement over an L-carnitine product relates to its bioavailability.
ALCAR is more easily absorbed from the gut, more readily crosses the blood-brain barrier6, and performs a broader range of activities in the body. As such, ALCAR is considered a more potent alternative to L-Carnitine. And there are numerous other potential health benefits associated with this supplement.
ALCAR has grown in popularity as various experts and influencers tout its benefits for those looking to lose weight, increase energy, and get a mental boost from a ‘super supplement’.
In addition to the energy-producing and fat-burning benefits, ALCAR is also promoted as a nootropic supplement and a powerful antioxidant with a range of purported cognitive and health benefits.
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More energy, less fat
Providing our bodies with additional sources can raise L-Carnitine stores, which may help our body convert stored and ingested fat into energy more effectively and efficiently.
With more L-Carnitine available, we can generate more energy during exercise or sport, with the potential for more efficient fat loss to enhance your body composition, and potentially improve cognitive function.
While more research is needed to affirm the various touted benefits, clinical evidence already exists that supports certain claims.
For instance, in one study2, 24 weeks of L-Carnitine supplementation “significantly increased muscle mass, improved physical effort tolerance and cognitive function in centenarians.”
A review3 of L-Carnitine conducted at Tufts University highlighted a range beneficial effects, with researchers stating: “Studies in older adults further showed that L-Carnitine intake can lead to increased muscle mass accompanied by a decrease in body weight and reduced physical and mental fatigue.”
And it appears that active individuals get more of a benefit than those who live a sedentary lifestyle. A small-scale study4confirmed that: “Acute L-Carnitine supplementation possibly affects exercise performance and triglycerides in athletes rather than sedentary men.”
And a study5 that looked at the role L-Carnitine supplementation can play in recovery after exercise stated that, “given the impact of the structural and symptomatic consequences of high-intensity exercise … facilitation of recovery from exercise by L-Carnitine supplementation is particularly beneficial to the healthy young active population.”
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Potential brain-boosting benefit
Through its beneficial action on the mitochondria in a range cells, including brain cells, various sources suggest that ALCAR can help to slow cognitive decline while increasing brain function by helping to improve memory, mood and alertness.
For instance, a meta-analysis7 that reviewed the efficacy of ALCAR in mild cognitive impairment (MCI) and mild early Alzheimer’s disease found that supplementing with 1.5–3g/day for at least three months resulted in beneficial effects on applied clinical scales and psychometric tests.
However, a scientific update8 published in 2017 that reviewed ALCAR in dementia and other cognitive disorders, determined that we need further studies “with homogeneous sample and longitudinal assessment” before recommending systematic clinical applications.
According to the authors of a 2017 meta-analysis9 , we also need more “well‐designed, randomised, placebo‐controlled trials of L‐Carnitine for cognition enhancement in cognitively healthy people, with large samples and relatively long‐term follow‐up”.
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From a broader wellness perspective, claims suggest that ALCAR can impact inflammation through its antioxidant action, which could potentially deliver various benefits to cardiovascular and brain health and recovery from exercise.
Part of its antioxidant function is linked to ALCAR’s ability to up-regulate levels of glutathione10, which is your body’s master antioxidant.
In one study11 conducted on rats in 2020, ALCAR “reduced the expressions of inflammation factors … in serum, aortic, and heart tissues.”
The study authors concluded that “ALCAR can inhibit the expressions of inflammatory factors and antioxidation to suppress the development of atherosclerosis by adjusting blood lipid in the myocardium of AS (atherosclerosis) rats.”
With such a broad range of benefits, a well-formulated, high quality ALCAR supplement may offer a smart way to improve fat loss, energy production and derive certain cognitive benefits.
- National Institutes of Health, Office of Dietary Supplements. Carnitine Fact Sheet for Health Professionals.https://ods.od.nih.gov/factsheets/Carnitine-HealthProfessional/
- Journal of the International Society of Sports Nutrition, The bright and the dark sides of L-carnitine supplementation: a systematic review. 21 September 2020. 17, Article number: 49 (2020)
- L-Carnitine Supplementation in Recovery after Exercise. Nutrients. 2018 Mar; 10(3): 349. Published online 2018 Mar 13. doi: 10.3390/nu10030349
- Effects of L-Carnitine Supplementation on Metabolic Utilization of Oxygen and Lipid Profile among Trained and Untrained Humans. Asian Journal of Sports Medicine: Vol.8, issue 1; e38707. Published Online: December 27, 2016
- l-Carnitine Supplementation in Recovery after Exercise. Nutrients 2018,10(3), 349; https://doi.org/10.3390/nu10030349
- Chapter Two – Metabolomics and Lipidomics of Ischemic Stroke. Advances in Clinical Chemistry, Volume 85, 2018, Pages 31-69
- Meta-analysis of double blind randomized controlled clinical trials of acetyl-L-carnitine versus placebo in the treatment of mild cognitive impairment and mild Alzheimer??s disease. International Clinical Psychopharmacology. April 2003, 18(2):61-71. doi:10.1097/01.yic.0000058280.28578.79
- Acetyl-L-Carnitine in Dementia and Other Cognitive Disorders: A Critical Update. Nutrients. 2020 May; 12(5): 1389. Published online 2020 May 12. doi: 10.3390/nu12051389
- L‐carnitine for cognitive enhancement in people without cognitive impairment. Cochrane Database Syst Rev. 2017 Mar; 2017(3): CD009374. Published online 2017 Mar 26. doi: 10.1002/14651858.CD009374.pub3
- Acetyl-L-carnitine-induced up-regulation of heat shock proteins protects cortical neurons against amyloid-beta peptide 1-42-mediated oxidative stress and neurotoxicity: implications for Alzheimer’s disease. J Neuroci Res. 2006 Aug 1;84(2):398-408. doi: 10.1002/jnr.20877.
- Anti-Inflammatory and Antioxidant Effects of Acetyl-L-Carnitine on Atherosclerotic Rats. Med Sci Monit. 2020; 26: e920250-1–e920250-11. Published online 2020 Jan 16. doi: 10.12659/MSM.920250
Author: Pedro van Gaalen
When he’s not writing about sport or health and fitness, Pedro is probably out training for his next marathon or ultra-marathon. He’s worked as a fitness professional and as a marketing and comms expert. He now combines his passions in his role as managing editor at Fitness magazine.