Chronic oral ingestion of L-carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise in humans. J Physiol. Skeletal muscle carnitine loading increases energy expenditure, modulates fuel metabolism gene networks and prevents body fat accumulation in humans.
Increasing skeletal muscle carnitine availability does not alter the adaptations to high-intensity interval training. Scand J Med Sci Sports. Article PubMed Google Scholar. Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med. Prevalence and patterns of dietary supplement use in elite Spanish athletes. J Int Soc Sports Nutr. Nutritional supplement use by Dutch elite and sub-elite athletes: does receiving dietary counseling make a difference?
Long-term administration of L-carnitine to humans: effect on skeletal muscle carnitine content and physical performance. Clin Chim Acta. Effect of L-carnitine supplementation on the body carnitine pool, skeletal muscle energy metabolism and physical performance in male vegetarians.
Endurance exercise training and L-carnitine supplementation stimulates gene expression in the blood and muscle cells in young athletes and middle aged subjects. Monatshefte Fur Chemie. L-Carnitine treatment reduces severity of physical and mental fatigue and increases cognitive functions in centenarians: a randomized and controlled clinical trial.
L-Carnitine supplementation increases Trimethylamine-N-oxide but not markers of atherosclerosis in healthy aged women. Ann Nutr Metab. Increased Trimethylamine N-oxide is not associated with oxidative stress markers in healthy aged women. Oxidative Med Cell Longev. Int J Mol Sci. Commercially marketed supplements for bodybuilding athletes. Sports Med. Strategies to enhance fat utilisation during exercise. Effect of L-carnitine supplementation on muscle and blood carnitine content and lactate accumulation during high-intensity sprint cycling.
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Carbohydrate ingestion augments L-carnitine retention in humans. J Appl Physiol The ubiquitin-proteasome system and skeletal muscle wasting. Essays Biochem. Mechanisms regulating skeletal muscle growth and atrophy. FEBS J. FoxO transcription factors: their roles in the maintenance of skeletal muscle homeostasis. Cell Mol Life Sci. Dietary L-carnitine alters gene expression in skeletal muscle of piglets.
Mol Nutr Food Res. Supplementation with l-carnitine downregulates genes of the ubiquitin proteasome system in the skeletal muscle and liver of piglets. L-Carnitine: an adequate supplement for a multi-targeted anti-wasting therapy in cancer. Clin Nutr. Nutr Metab Lond. Supplemental carnitine affects the microRNA expression profile in skeletal muscle of obese Zucker rats.
BMC Genomics. L-Carnitine supplement reduces skeletal muscle atrophy induced by prolonged hindlimb suspension in rats.
Appl Physiol Nutr Metab. Acetyl-L-carnitine administration increases insulin-like growth factor 1 levels in asymptomatic HIVinfected subjects: correlation with its suppressive effect on lymphocyte apoptosis and ceramide generation. Clin Immunol. The effects of L-carnitine L-tartrate supplementation on hormonal responses to resistance exercise and recovery.
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Beneficial effects of l-carnitine supplementation for weight management in overweight and obese adults: an updated systematic review and dose-response meta-analysis of randomized controlled trials. Pharmacol Res. Eur J Appl Physiol. Effect of L-carnitine supplementation in comparison with moderate aerobic training on serum inflammatory parameters in healthy obese women. J Sports Med Phys Fitness. Effects of nine weeks L-Carnitine supplementation on exercise performance, anaerobic power, and exercise-induced oxidative stress in resistance-trained males.
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J Cardiovasc Pharmacol. Marked elevation in plasma trimethylamine-N-oxide TMAO in patients with mitochondrial disorders treated with oral l-carnitine.
Mol Genet Metab Rep. Gut flora metabolism of phosphatidylcholine promotes cardiovascular disease. Red meat consumption and mortality: results from 2 prospective cohort studies. Arch Intern Med. Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. N Engl J Med. Gut microbiota-dependent trimethylamine N-oxide TMAO pathway contributes to both development of renal insufficiency and mortality risk in chronic kidney disease.
Circ Res. Trimethylamine N-oxide and prognosis in acute heart failure. TMAO is associated with mortality: impact of modestly impaired renal function. Sci Rep. J Am Heart Assoc. However, one analysis of nine studies — mostly in obese individuals or older adults — found that people lost an average of 2. More research is needed to confirm the benefits of L-carnitine in a younger, more active population. While it may aid in weight loss for obese individuals or older adults, a thorough diet and exercise regimen must be in place first.
Although the cellular mechanism of L-carnitine suggests it could benefit weight loss, its effects — if present at all — are small. Some animal studies suggest that the acetyl form, acetyl-L-carnitine ALCAR , may help prevent age-related mental decline and improve markers of learning 30 , In a day study, people with alcohol addictions who took 2 grams of acetyl-L-carnitine per day experienced significant improvements in all measures of brain function L-carnitine — specifically acetyl-L-carnitine — can have beneficial effects on brain function in various diseases.
Some studies demonstrate a potential for reducing blood pressure and the inflammatory process associated with heart disease 23 , In one study, 2 grams of acetyl-L-carnitine per day resulted in an almost point drop in systolic blood pressure — the top number of a blood pressure reading and an important indicator of heart health and disease risk L-carnitine is also linked to improvements in patients with severe heart disorders, such as coronary heart disease and chronic heart failure 40 , One month study observed a reduction in heart failure and deaths among participants who took L-carnitine supplements However, several studies note mild benefits associated with larger or more long-term doses 43 , 44 , This differs from supplements like caffeine or creatine , which can directly enhance sports performance.
L-carnitine may also reduce symptoms of type 2 diabetes and its associated risk factors 52 , 53 , One study of people with type 2 diabetes taking anti-diabetic medication indicated that carnitine supplements significantly reduced blood sugar levels , compared to a placebo Research suggests that L-carnitine may aid exercise performance and treat health conditions like heart disease and type 2 diabetes.
For most people, 2 grams or less per day is relatively safe and free from any serious side effects. In one study, people who took 3 grams every day for 21 days experienced no negative effects However, there were some mild side effects, including nausea and stomach discomfort 24 , High levels of TMAO are linked to an increased risk of atherosclerosis — a disease which clogs your arteries 59 , Doses of 2 grams or less per day seem to be well tolerated and safe for most people.
Tentative evidence suggests L-carnitine supplements might increase your risk of atherosclerosis. You can get small amounts of L-carnitine from your diet by eating meat and fish 4 , 5. The best sources of L-carnitine are 4 :. As noted before, your body can also produce this substance naturally from the amino acids methionine and lysine if your stores are low. For these reasons, L-carnitine supplements are only necessary in special cases, such as disease treatment. The main dietary sources of L-carnitine are meat, fish and some other animal products, such as milk.
A healthy individual can also produce sufficient amounts within the body. For this reason, L-carnitine levels are often lower in vegetarians and vegans, since they restrict or avoid animal products 6 , Therefore, vegetarians and vegans may want to consider L-carnitine supplements. However, no studies have confirmed the benefits of carnitine supplements in these specific populations.
To comply with the new e-Privacy directive, we need to ask for your consent to set the cookies. Learn more. In order to lose fat and get shredded, many people will go to extreme lengths. They might go on some new fad diet, add in some cardio to their workout regimen, or grab an over-the-counter weight loss miracle pill that they heard about on a daily television show.
They might even do a combination of all of these things. What if there was another way. What if you could buy one supplement that has been proven to help you burn off fat by converting it into energy? L-Carnitine is an important amino acid.
It plays a significant role in boosting your body's metabolism. It does this by improving mitochondrial function and increasing cellular energy. Many athletes use it to help them burn fat, enjoy enhanced recovery and prevent muscle fatigue. Trace amounts are found in the liver and the blood as well.
The body can produce L-Carnitine on its own with the help of the amino acids methionine and lysine. However, supplemental L-Carnitine can help to make up for deficiencies in these amino acids, especially among people who eat plant-based diets and don't get adequate amounts of them from animal products.
Some people also have genetic conditions that make it difficult for them to produce L-Carnitine and can benefit from L-Carnitine supplementation. L-Carnitine works by transporting fatty acids from food into the mitochondria of the cell. There, they are converted into energy. This allows you to burn fat during workouts, and at the same time, it will prevent muscle failure, fatigue, and that sluggish feeling many people experience, especially during a dieting phase.
The energy that is produced from the fatty acids can be used by the heart, brain, and muscle, causing a positive effect on all three of these parts in the body.
Besides fat loss, other benefits of L-Carnitine include increased endurance and enhanced muscle recovery. Many athletes notice a significant boost in their performance when they supplement with L-Carnitine. They may also experience better muscle gains and have an easier time getting back into the gym after difficult workouts. L-Carnitine supplementation can also help with cognition and better brain function.
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