I have been investigating the beneficial effects of acetyl-L-carnitine (ALCAR) on the brain for cognitive function for a long time. After 2010, I also started researching metabolic health and fitness benefits as I found compelling studies published in peer-reviewed journals.
Since then, I have also used ALCAR as a supplement for various reasons that I briefly explain in this article. Although some people reported side effects, I haven’t experienced any adverse effects by using 500 mg daily for over a decade, so I continue using it safely and monitoring my progress through blood work.
I only write about essential and well-researched supplements with compelling bodily and cognitive benefits. ALCAR is one of them that gained my confidence; therefore, I pass along my knowledge and experience.
Unlike other hyped supplements on the market, it is not an ordinary supplement and is not hyped. Instead, it is widely used by informed athletes and fitness enthusiasts, especially those following time-restricted eating and ketogenic diets.
An Overview of Carnitine, Deficiency Symptoms, and Why I Prefer ALCAR
Our body naturally produces carnitine. It is a critical molecule for energy metabolism. Our mitochondria need it to metabolize fat. More specifically, it serves as a transport agent for fatty acids.
As mentioned in my previous articles, mitochondria are the energy powerhouse of our cells. Our muscles store carnitine, but it can also exist in the bloodstream and the liver in small amounts.
Like vitamin B12, Creatine, Vitamin D3, DHA, L-Carnosine, and Taurine, plant sources do not include carnitine.
Therefore, those who follow strict plant-based diets need to supplement these nutrients with support from qualified healthcare professionals. I explained them in an article titled Six Important Nutrients We Can’t Get from Vegetables or Fruits Adequately.
Carnitine is mainly found in animal products such as meat and fish. However, it is also available in supplement form in health and sports shops without a prescription. I purchase mine from reliable and accredited sources in the US.
Contrary to common beliefs in plant-based eating circles, carnitine deficiency is a genuine and extensively documented condition in the literature. During my time following a vegan diet in my younger years, I experienced a decline in energy levels, which I later discovered was due in part to carnitine deficiency.
According to this NIH book, carnitine deficiency refers to low levels of carnitine in the body, which can occur for various reasons. Primary carnitine deficiency is a genetic disorder inherited in an autosomal recessive manner, with symptoms ranging from asymptomatic to sudden onset.
Secondary carnitine deficiency can stem from decreased carnitine intake or, more commonly, increased renal excretion of acylcarnitine. Various health conditions can lead to secondary carnitine deficiency by reducing the body’s carnitine levels. This can occur through increased excretion in urine or decreased absorption from food.
Conditions contributing to secondary carnitine deficiency include liver disease, kidney disease (particularly with dialysis), digestive disorders affecting absorption, malnutrition, mitochondrial disease, specific metabolic disorders, and certain medications like valproate.
Timely diagnosis and treatment with L-carnitine are crucial to prevent complications associated with deficiencies.
Symptoms of carnitine deficiency can vary from person to person, ranging from none to mild to severe. They may manifest during fasting, intense physical activity, or illness. Common symptoms include decreased or weak muscle tone, fatigue, irritability, delayed motor development, poor feeding in infants, and symptoms of low blood sugar if the liver is impacted.
Besides, heart-related symptoms like swelling or shortness of breath may occur if the heart is affected. Since these symptoms can resemble other health conditions, it’s essential to consult a qualified healthcare provider for an accurate diagnosis.
As documented in this resource, carnitine deficiency can be diagnosed by a neurologist or geneticist, often during standard newborn screening tests. Diagnosis typically involves a health history, physical examination, and various tests.
Blood tests evaluate carnitine levels, creatine kinase for muscle damage, and liver enzymes, while urine tests detect ketones. Exercise tests identify metabolic issues, genetic tests confirm primary carnitine deficiency, and heart tests, like echocardiography, assess heart function.
Acetyl-L-carnitine (ALCAR) is an antioxidant within the body, particularly in the brain, where it helps mitigate oxidative stress induced by fat metabolism. While L-carnitine L-tartrate and Propionyl-L-carnitine are two other forms of carnitine, my expertise lies primarily in ALCAR, especially in its cognitive applications.
In some countries, ALCAR is categorized and sold as a nootropic. I introduced nootropics in an article titled What We Know about Nootropics & Why They Matter. Nootropics enhance our cognition, contributing to focus, attention, memory, task switching, and problem-solving capabilities.
When reviewing the medical and fitness literature, I came across various use cases of ALCAR. Some of the exciting benefits are its use to prevent memory loss, improve physical and mental tiredness, reduce cravings, slow Alzheimer’s or other dementia disease symptoms, improve mood, reduce nerve pain, and increase sperm count.
Even though research findings on these points are still inconclusive, researchers highlight the potential benefits of ALCAR, recommending further investigation. In this story, I want to summarize four use cases for ALCAR based on my research and personal experience.
1 — Cognitive Function and Brain Health
I came across numerous studies on humans and animals highlighting the benefits of ALCAR in reversing cognitive decline, especially in neurodegenerative conditions like Alzheimer’s disease.
A double-blind, parallel-design pilot study of Acetyl Levocarnitine in patients with Alzheimer’s disease published in JAMA Neurology suggests that:
“Acetyl levocarnitine may retard the deterioration in some cognitive areas in patients with Alzheimer’s disease and stress the need for a larger study of this drug.”
“Treatment of mice with ALCAR significantly attenuated spatial learning and memory impairment on the Morris maze-water behavioral task and also importantly reduced degeneration in size and number of cholinergic cells in the nucleus basalis magnocellularis of the basal forebrain [the brain region for learning and memory].” In simple terms, the attention, memory, and learning of mice increased.
“Several studies explored the effects of acetyl-L-carnitine (ALC) in dementia, suggesting a role in slowing down cognitive decline.”
Researchers believe that
“The underlying mechanisms may include restoring of cell membranes and synaptic functioning, enhancing cholinergic activity, promoting mitochondrial energy metabolism, protecting against toxins, and exerting neurotrophic effects.”
They also commented that
“The effects of ALC on the gut-liver-brain axis seem to identify the category of patients in which the new insights contribute most to the mechanisms of action of ALC, likely being the liver metabolism and the improvement of hepatic detoxifying mechanisms the primary targets.”
2 — Fat Metabolism and Weight Loss
The research findings on carnitine supplementation for weight loss and fat reduction look murky, even though we know the role of carnitine in fat mobilization.
Some studies offer compelling results on its benefits for fat metabolization leading to potential fat loss, and some offer no difference. Rather than going into the details of multiple studies, I provide a meta-analysis of studies that give us the bigger picture.
For example, a systematic review and meta-analysis of randomized controlled trials have examined the effect of carnitine on adult weight loss.
The paper published in Obesity Treatment/Etiology and Pathophysiology journal in 2016 concluded that “receiving the carnitine resulted in weight loss. Using multiple-treatments meta-analysis of the drugs and non-pharmacotherapy options seem to be insightful areas for research.”
However, when I reviewed multiple papers on animal studies, some of the studies on mice showed no difference.
Interestingly, a study on obese cats produced positive results. Researchers of this paper concluded that “Dietary l-carnitine supplementation appeared to have a metabolic effect in overweight cats undergoing rapid weight loss that facilitated fatty acid oxidation.”
3 — Insulin Sensitivity and Diabetes Support
In addition to the weight loss, fitness, and cognitive benefits of ALCAR, I am also interested in its benefits for type II diabetes, especially in dealing with insulin resistance and increasing insulin sensitivity toprevent metabolic syndrome.
ALCAR has been shown to enhance insulin sensitivity in various studies. Insulin sensitivity refers to how effectively cells respond to insulin and take up glucose from the bloodstream. By improving insulin sensitivity, ALCAR may help cells utilize glucose more efficiently, potentially lowering blood sugar levels.
For example, this paper titled “Caloric Restriction and L-Carnitine Administration Improves Insulin Sensitivity in Patients With Impaired Glucose Metabolism,” published in the Journal of Parental and Enteral Nutrition, provides compelling results.
ALCAR plays a role in mitochondrial function and energy production within cells. It helps transport fatty acids into mitochondria, converting them into energy. This process is essential for glucose metabolism and insulin action in the body.
Chronic inflammation is associated with insulin resistance and the development of type 2 diabetes. ALCAR has anti-inflammatory properties, which may help reduce inflammation and improve insulin sensitivity.
ALCAR has neuroprotective properties and may help prevent nerve damage often associated with diabetes, such as diabetic neuropathy. By preserving nerve function, ALCAR may help alleviate neuropathy symptoms, such as pain and numbness.
ALCAR acts as an antioxidant, helping to neutralize harmful free radicals in the body. Oxidative stress is implicated in the development of insulin resistance and complications associated with diabetes. By reducing oxidative stress, ALCAR may help protect against diabetes-related damage to cells and tissues.
University of Rochester Medical Center points out that we may need a total and free carnitine test if we are being treated for type II diabetes, cancer, an enlarged heart, or kidney disease.
In some cases, these conditions can affect how patients use carnitine. As the resource points out, test results depend on our physical condition and age. However, a ratio greater than 0.4 suggests a carnitine deficiency.
4 — Fitness Improvement and Performance
Over the last two decades, I have read many scientific papers from peer-reviewed journals and hundreds of experimental studies in fitness magazines on the benefits of ALCAR in athletic performance.
While scientific studies show mixed results, the experimental and anecdotal evidence depict positive results on the benefits of supplementation. Due to the scope of my article, I provide two sample studies.
A paper titled “The Effects of Acute L-carnitine Supplementation on Endurance Performance of Athletes” published in the Journal of Strength and Conditioning Research found:
“The running speeds corresponding to specific lactate concentrations were increased, and lactate and heart rate responses to the running speeds were decreased in both supplemented groups compared with placebos.” Besides, researchers identified a significant reduction in heart rate.
Another paper titled “Effects of Prolonged L-Carnitine Administration on Delayed Muscle Pain and CK Release After Eccentric Effort” published in the International Journal of Sports Medicine concluded:
“L-carnitine has a protective effect against pain and damage from the eccentric effort. This effect is mainly attributed to the vasodilatation property of the compound, which both improves the energetic metabolism of the damaged muscle and enhances the wash-out of algogenic metabolites.”
Conclusions and Takeaways
The research into carnitine supplementation, especially the acetyl form, looks promising even though the results are still inconclusive.
The major benefit of the acetyl form of carnitine is the ability to bypass the brain-blood barrier, giving a competitive advantage to the brain. Only specific molecules can pass this well-controlled biological barrier.
Therefore, I am more interested in ALCAR (Acetyl L Carnitine) than other forms of carnitine. In addition, ALCAR has antioxidant and anti-inflammatory effects, protecting the brain from oxidative stress and neuroinflammation.
I only focused on four use cases in this article: cognitive health, metabolic health, insulin sensitivity, and fitness performance.
However, the medical and fitness literature also includes other important use cases, such as increasing the production of red blood cells, reducing muscle soreness, increasing stamina, and improving recovery after heavy workouts. I plan to cover these benefits in another article.
ALCAR is an essential supplement for me as I am on time-restricted eating, including long-term fasting, and my body is fat-adapted, requiring more carnitine for fat mobilization, giving me the needed energy.
In certain nutrition circles, concerns have been raised about the consumption of carnitine-rich foods, reportedly leading to increased levels of the metabolite TMAO, particularly in the context of atherosclerosis. Red meat consumption has often been singled out in these discussions.
However, it’s worth noting that fish, often recommended as a healthier dietary option, actually results in higher TMAO (trimethylamine N-oxide) levels than red meat.
Therefore, based on my research and personal experience with moderate red meat consumption over the past decade, I respectfully disagree with the allegations regarding its negative impact.
The Science Director for NutriGuard, Mark McCarty, explains this complex situation based on his review of the Mayo Clinic Proceedings in a video on YouTube.
In essence, our bodies naturally produce carnitine, which plays a crucial role in energy metabolism. It’s a vital molecule that our mitochondria rely on to metabolize fat effectively. Essentially, it acts as a carrier for fatty acids during this process.
Carnitine deficiency is a genuine and well-documented condition in the literature. Therefore, timely diagnosis and treatment with L-carnitine are crucial to prevent complications associated with deficiencies.
Thank you for reading my perspectives. I wish you a healthy and happy life.
If you found this story helpful, you may also check out my other articles on NewsBreak. As a postdoctoral researcher and executive consultant, I write about important life lessons based on my decades of research and experience in cognitive, metabolic, and mental health.
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