The absence of myocyte regeneration causes fatal consequences over time. Several times, gym trainers have recommended L-carnitine to gymgoers for better performance. L-carnitine is linked to improving theВ symptoms of type-2 diabetes В and associated complications.

OneВ study В revealed that people suffering from type 2 diabetes who consumed anti-diabetic medication along with L-carnitine reported lower blood sugar levels as compared to those taking a placebo. PCOS В is a hormonal condition that leads to enlarged, cystic ovaries. L-carnitine has been shown to improve brain function, specifically memory, cognition, and mood.

Studies have proven L-carnitine's ability to improve cognitive performance in patients with mild cognitive impairment and age-related memory decline. OneВ study В discovered that using L-carnitine supplements for three months to one year halted or reduced the progression of cognitive decline.

L-carnitine may also be beneficial for mood. AВ study В found that levels of L-carnitine and depression are related. Supplementation with L-carnitine helped the trial group members decrease theВ symptoms of depression.

Additionally, L-carnitine may be beneficial to the brain. It has been demonstrated to have antioxidant capabilities, which can help protect brain cells from oxidative stress and damage. L-carnitine is an essential nutrient, which means your body makes enough L-carnitine for regular functioning.

L-carnitine LC is available as a dietary supplement and is taken by many athletes. It is a must-have for anyone trying to lose weight. Since it boosts fat and carbohydrate metabolism, you are able to melt away all the excess fat in your body. When paired with a proper diet and exercise, L-carnitine supplements can result in significant weight loss.

According to experts, consumingВ 2 grams В or less of L-carnitine is generally considered safe for healthy adults. Mild side effects, such as stomach discomfort and nausea, may happen to some people.

The most common sources of L-carnitine are beef, pork, fish, chicken, and milk. This, too, gets eliminated if you are lactose-intolerant or vegan. Fortunately, there are severalВ L-carnitine supplements В on the market that you can rely on.

When we consume nutrients in the form of food, our body has to put in a lot of effort to break it down, process it, and then extract nutrients from it. Supplements make it easy for your body to absorb all nutrients. They are readily available for absorption and also give you just the right dosage.

While consuming supplements, make sure you follow the directions. L-carnitine overdose symptoms include nausea, vomiting, pain in the abdomen, diarrhea, and a fishy body odor. Well, the best way to consume L-carnitine is by consuming supplements that include it as an ingredient, especially if you want to lose weight.

Fortunately, we have one that you can rely on. Slow BurnВ from Wellbeing Nutrition is a scientifically crafted L-carnitine weight loss supplement that comes with other amazing ingredients like chromium and caffeine.

These ingredients can help you: В. All you need is 1 capsule of Slow Burn each day before your workout for best results. These capsules are created using delayed-release technology. Many patients with end-stage renal disease, particularly those on hemodialysis, become carnitine insufficient.

Low levels of carnitine in blood and muscle stores can contribute to anemia, muscle weakness, fatigue, altered levels of blood fats, and heart disorders.

Numerous studies suggest that high doses of supplemental carnitine often injected administered to patients on maintenance hemodialysis can correct some or all of these symptoms [ 26 ]. However, most of these studies had small numbers of participants and were not double-blind clinical trials.

The authors of a meta-analysis of these studies concluded that carnitine supplements might help patients manage their anemia but not their blood-lipid profiles, and that the effects of these supplements on exercise capacity and heart disorders were inconclusive [ 26 ].

Clinical and psychometric assessment scores were better, and improvements determined by clinicians were greater in supplement users than in the placebo groups [ 30 ].

In contrast, a Cochrane Review of 15 clinical trials including 13 of those in the meta-analysis described above had somewhat different findings [ 29 ]. The results showed that the supplementation decreased symptom severity at 12 and 24 weeks but not at 52 weeks.

Similarly, acetyl-L-carnitine supplements improved scores on the Mini Mental State Examination at 24 weeks but not at 12 or 52 weeks and had no effect on the severity of dementia, functional ability, or overall clinical global impression scores.

The authors of the Cochrane Review noted that results from studies conducted more recently were less positive than those from earlier studies; they concluded that the routine clinical use of acetyl-L-carnitine supplements to treat the signs and symptoms of dementia was not justified.

Carnitine plays a role in transporting long-chain fatty acids in the myocardial mitochondria, where they are metabolized via oxidation for energy. It is also involved in moderating oxidative stress [ 33 , 34 ] and might decrease markers of inflammation [ 35 ].

During ischemic events, carnitine prevents fatty acid ester accumulation, which can lead to fatal ventricular arrhythmias [ 34 ]. For these reasons, researchers are examining whether carnitine affects cardiovascular health. Clinical trials examining the effects of carnitine supplements on CVD have had mixed results.

A meta-analysis of 13 clinical trials included a total of 3, adults with acute myocardial infarction who took either L-carnitine from 2. The study found that L-carnitine significantly reduced rates of all-cause mortality, ventricular arrhythmias, and new-onset angina but did not affect risk of heart failure or myocardial reinfarction [ 34 , 36 ].

The carnitine dose and duration of the clinical trial did not appear to affect outcomes. These benefits did not vary by supplement dose or study duration.

However, L-carnitine did not affect rates of all-cause mortality or performance on a timed walking test. Other research has raised concerns about the negative cardiovascular effects of chronic exposure to carnitine. A study that included 2, adults age 54—71 years undergoing elective cardiac evaluation found that L-carnitine is metabolized by intestinal microbiota to trimethylamine-N-oxide TMAO , a proatherogenic substance that is associated with increased CVD risk [ 38 ].

Because of differences in intestinal bacteria composition, omnivorous study participants produced more TMAO than vegans or vegetarians after consumption of L-carnitine. The study also found dose-dependent associations between fasting plasma L-carnitine concentrations and risk of coronary artery disease, peripheral artery disease, and CVD, but only in participants with concurrently high TMAO levels.

A clinical trial also found potentially deleterious outcomes in individuals age 58 to 75 years with metabolic syndrome who received 1 g supplemental L-carnitine or placebo twice a day for 6 months [ 39 ].

Although the results showed no differences in total plaque volume between groups, total cholesterol and low-density lipoprotein cholesterol levels were higher in participants taking L-carnitine. L-carnitine supplementation was also associated with 9. Peripheral artery disease is a vascular disorder usually caused by atherosclerosis and its resulting arterial stenosis and occlusion.

It is prevalent among older adults, although it is often underdiagnosed [ 40 , 41 ]. Researchers have examined whether propionyl-L-carnitine, an acyl derivative of L-carnitine, mitigates the cramping leg pain of intermittent claudication, the main symptom of peripheral artery disease, but findings from studies have been mixed.

In one trial, participants supplemented with propionyl-L-carnitine had improved peak walking times walking until pain could not be tolerated , self-reported improvements in walking distance and speed, and decreased pain. The other two trials showed no benefit of propionyl-L-carnitine on peak walking time compared with placebo.

Insulin resistance plays an important role in the development of type 2 diabetes. Because insulin resistance may be associated with mitochondrial dysfunction and a defect in fatty-acid oxidation in muscle [ 43 , 44 , 45 , 46 ], carnitine supplementation has been studied for its possible effects on insulin resistance and diabetes.

A meta-analysis of 41 randomized clinical trials examined the effects of L-carnitine supplementation on glycemic markers in 2, men and women age 18 years and older [ 47 ]. Most participants had health conditions such as type 2 diabetes, obesity, polycystic ovary syndrome, or nonalcoholic fatty liver disease.

L-carnitine supplements at doses of 0. Other meta-analyses have had a narrower focus, examining only studies in specific populations.

The L-carnitine improved measures of insulin resistance, and the benefits at 12 months exceeded those at 3 months. A systematic review and meta-analysis of four randomized clinical trials all of which were included in the meta-analysis described above with a total of adults with type 2 diabetes compared the metabolic effects of L-carnitine with those of placebo [ 44 ].

Additional clinical trials with larger samples are needed to determine whether L-carnitine supplements can reduce the risk of diabetes or the severity of its clinical manifestations. Carnitine might play a role in sperm maturation, sperm motility, and spermatogenesis [ 49 ].

It might also reduce oxidative stress, which could improve oocyte growth and maturation [ 50 ]. Therefore, researchers are examining whether supplemental carnitine improves sperm count, concentration, and motility as well as pregnancy rates.

Compared to placebo, supplemental carnitine improved sperm motility by 7. A Cochrane Review assessed the effectiveness of carnitine supplementation on male subfertility delays in conception due to low sperm concentration [ 52 ].

In some trials, carnitine was compared with placebo, whereas in others, it was compared with antioxidants such as vitamin C or vitamin E or a control group that received no treatment. Carnitine supplementation increased sperm motility and concentration at some timepoints e.

Researchers have also examined whether carnitine might improve ovulation and pregnancy rates in females with polycystic ovary syndrome PCOS , a condition that commonly causes infertility.

Individuals in the group taking L-carnitine had Additionally, a review showed that L-carnitine could reduce total and LDL bad cholesterol while increasing HDL good cholesterol in people at risk for heart disease The evidence is mixed when it comes to the effects of L-carnitine on sports performance, but it may offer some benefits.

This differs from supplements like caffeine or creatine , which can directly enhance sports performance 22 , A recent review of 41 studies concluded that L-carnitine supplementation could reduce fasting blood sugar and hemoglobin A1c a marker of long-term blood sugar levels while also improving insulin sensitivity in people with diabetes, overweight, or obesity According to the authors of the review, L-carnitine is believed to work by altering insulin receptors and changing the expression of specific genes that regulate sugar metabolism It may also help improve the function of beta cells, which are cells in the pancreas that are responsible for producing insulin In one review of 12 studies, acetyl-L-carnitine significantly reduced symptoms of depression compared with placebo Interestingly, several of the studies included in this review also found that acetyl-L-carnitine was as effective as antidepressant medications but caused fewer adverse effects Research suggests that L-carnitine may aid exercise performance and treat health conditions like heart disease, depression, and type 2 diabetes.

For most people, taking 2 grams g or less per day is relatively safe and free from any serious side effects Some research has also used doses of up to 4, mg per day However, there were some mild side effects, including heartburn and indigestion However, L-carnitine supplements may raise your blood levels of trimethylamine-N-oxide TMAO over time.

High levels of TMAO are linked to an increased risk of atherosclerosis — a disease that clogs your arteries Doses of 2 g or less per day seem to be well tolerated and safe for most people. However, L-carnitine may increase levels of TMAO, which could be linked to an increased risk of plaque build-up.

You can get small amounts of L-carnitine from your diet by eating meat and dairy products The best sources of L-carnitine are 35 :. 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 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 Therefore, vegetarians and vegans may want to consider L-carnitine supplements, which can help normalize carnitine levels in the blood and muscles In fact, one study found that taking 1.

On the other hand, another study showed that L-carnitine supplementation had no effect on muscle strength or markers of inflammation in older women The risk of deficiency is also higher for those with diseases like cirrhosis and kidney disease.

If you have one of these conditions, a supplement may be beneficial 40 , Specific populations may benefit from L-carnitine supplements. This includes older adults and people who rarely or never eat meat.

Although dosage varies from study to study, here is an overview of the use and dose for each form 13 , 19 , 33 :. Although the recommended dose varies, around —4, mg 0. Studies also support its use for health, brain function, and disease prevention.

Supplements may also benefit those with lower levels, such as older adults, vegans, and vegetarians. Of the different forms, acetyl-L-carnitine and L-carnitine are the most popular and seem to be the most effective. Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.

There are several effective supplements that can help you burn body fat. This article lists 5 natural fat burners that are supported by science.

In both trials, the effect of carnitine was greater in the most severe cases of asthenozoospermia reduced sperm motility at baseline , However, a pooled analysis of the two trials that employed ALCAR found no significant effect of ALCAR and L-carnitine on sperm concentration, motility, and morphology Evidence from larger scale clinical trials is still needed to determine whether L-carnitine and ALCAR could play a role in the treatment of male infertility.

Frailty is a syndrome prevalent among geriatric populations and characterized by a functional decline and a loss of independence to perform the activities of daily living. Frailty in individuals may include at least three of the following symptoms: unintentional weight loss, exhaustion poor endurance , weakness low grip strength , slowness, and physical inactivity It is believed that early stages of frailty are amenable to interventions that could avert adverse outcomes, including the increased risk of hospitalization and premature death The suggestion that carnitine deficiency may lead to frailty through mitochondrial dysfunction has been examined in one trial.

This randomized , double-blind , placebo -controlled trial in 58 older adults identified as "pre-frail" found an decrease in a Frailty Index score and an improvement in the hand grip test in individuals supplemented with L-carnitine 1.

However, there was no difference in Frailty Index and hand grip test scores between supplemental L-carnitine and placebo groups. Loss of skeletal muscle mass is associated with a decrease in muscle strength and occurs with aging , as well as in several pathological conditions Based on preclinical studies, it has been suggested that L-carnitine supplementation could limit the imbalance between protein anabolism synthesis and catabolism degradation that leads to skeletal muscle wasting A randomized , double-blind , placebo -controlled trial in 28 older women ages, years found no effect of L-carnitine supplementation 1.

One major limitation of this study beyond its retrospective design is that patients who received L-carnitine had a significantly different clinical presentation; in particular, liver dysfunction was significantly more severe in these patients than in those who were not supplemented Muscle cramps are involuntary and painful contractions of skeletal muscles.

Two uncontrolled studies conducted in participants with cirrhosis found that L-carnitine supplementation was safe to use at doses of 0. However, whether supplemental L-carnitine can be efficacious to limit the incidence of muscle cramps in patients with cirrhosis remains unknown. An open-label , non-randomized trial in 69 patients with either type 1 or type 2 diabetes mellitus found a reduction in the incidence of muscle cramps and an improvement in the quality of life of those prescribed 0.

In contrast, there is little evidence to date to suggest that supplemental L-carnitine could reduce muscle cramps in patients undergoing hemodialysis Well-designed trials are necessary to examine whether L-carnitine could be helpful in the management of cramps.

Interest in the potential of L-carnitine supplementation to improve athletic performance is related to its important roles in energy metabolism.

However, the content carnitine in skeletal muscle, phosphocreatine, ATP , glycogen , and lactate, as well as measures of physical performance during exercise were equivalent between vegetarians and omnivores.

While L-carnitine supplementation normalized plasma carnitine concentration in vegetarians to that observed in omnivores, there was no effect on energy metabolism and physical performance compared to no supplementation and between vegetarians and omnivores The normal rate of L-carnitine biosynthesis in humans ranges from 0.

Thus, a 70 kg 1b person would synthesize between 11 and 34 mg of carnitine per day. Meat, poultry, fish, and dairy products are the richest sources of L-carnitine, while fruit, vegetables, and grains contain relatively little L-carnitine. Non-milk-based infant formulas e. Some carnitine-rich foods and their carnitine content in milligrams mg are listed in Table 1.

Intravenous L-carnitine is available by prescription only for the treatment of primary and secondary L-carnitine deficiencies Oral L-carnitine is available by prescription for the treatment of primary and secondary L-carnitine deficiencies It is also available without a prescription as a nutritional supplement ; supplemental doses usually range from 0.

Acetyl-L-carnitine ALCAR is available without a prescription as a nutritional supplement. In addition to providing L-carnitine, it provides acetyl groups that may be used in the formation of the neurotransmitter , acetylcholine.

Supplemental doses usually range from 0. Propionyl-L-carnitine is not approved by the US FDA for use as a drug to prevent or treat any condition. It is, however, available without prescription as a nutritional supplement.

See Figure 1 for the chemical structures of L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine. In general, L-carnitine appears to be well tolerated; no toxic effects have been reported in relation to intakes of high doses of L-carnitine.

L-Carnitine supplementation may cause mild gastrointestinal symptoms, including nausea, vomiting, abdominal cramps, and diarrhea.

Acetyl-L-carnitine ALCAR has been reported to increase agitation in some Alzheimer's disease patients Despite claims that L-carnitine or ALCAR might increase seizures in some individuals with seizure disorders , these are not supported by any scientific evidence Only the L- isomer of carnitine is biologically active; the D-isomer may actually compete with L-carnitine for absorption and transport, thereby increasing the risk of L-carnitine deficiency 4.

Supplements containing a mixture of the D- and L-isomers D,L-carnitine have been associated with muscle weakness in patients with kidney disease. Long-term studies examining the safety of ALCAR supplementation in pregnant and breast-feeding women are lacking Pivalic acid combines with L-carnitine and is excreted in the urine as pivaloylcarnitine, thereby increasing L-carnitine losses see also Secondary carnitine deficiency.

Consequently, prolonged use of pivalic acid-containing antibiotics, including pivampicillin, pivmecillinam, pivcephalexin, and cefditoren pivoxil Spectracef , can lead to secondary L-carnitine deficiency The anticonvulsant valproic acid Depakene interferes with L-carnitine biosynthesis in the liver and forms with L-carnitine a valproylcarnitine ester that is excreted in the urine.

However, L-carnitine supplements are necessary only in a subset of patients taking valproic acid. There is insufficient evidence to suggest that nucleoside analogs used in the treatment of HIV infection i.

Originally written in by: Jane Higdon, Ph. Linus Pauling Institute Oregon State University. Updated in April by: Victoria J. Drake, Ph. Updated in July by: Barbara Delage, Ph. Reviewed in December by: Tory M.

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J Peripher Nerv Syst. Hart AM, Wilson AD, Montovani C, et al. Acetyl-l-carnitine: a pathogenesis based treatment for HIV-associated antiretroviral toxic neuropathy.

Herzmann C, Johnson MA, Youle M. Long-term effect of acetyl-L-carnitine for antiretroviral toxic neuropathy. HIV Clin Trials. Osio M, Muscia F, Zampini L, et al. Acetyl-l-carnitine in the treatment of painful antiretroviral toxic neuropathy in human immunodeficiency virus patients: an open label study.

Valcour V, Yeh TM, Bartt R, et al. Acetyl-l-carnitine and nucleoside reverse transcriptase inhibitor-associated neuropathy in HIV infection. HIV Med. Youle M, Osio M. A double-blind, parallel-group, placebo-controlled, multicentre study of acetyl L-carnitine in the symptomatic treatment of antiretroviral toxic neuropathy in patients with HIV-1 infection.

Tesfaye S, Selvarajah D. Advances in the epidemiology, pathogenesis and management of diabetic peripheral neuropathy. Diabetes Metab Res Rev. Dy SM, Bennett WL, Sharma R, et al. AHRQ Comparative Effectiveness Reviews.

Preventing complications and treating symptoms of diabetic peripheral neuropathy. Rockville MD : Agency for Healthcare Research and Quality US ; Rockville MD : Agency for Healthcare Research and Quality US ; Mar Report No. Rolim LC, da Silva EM, Flumignan RL, Abreu MM, Dib SA.

Acetyl-L-carnitine for the treatment of diabetic peripheral neuropathy. Cochrane Database Syst Rev. Sima AA, Calvani M, Mehra M, Amato A. Acetyl-L-carnitine improves pain, nerve regeneration, and vibratory perception in patients with chronic diabetic neuropathy: an analysis of two randomized placebo-controlled trials.

Diabetes Care. Li S, Chen X, Li Q, et al. Effects of acetyl-L-carnitine and methylcobalamin for diabetic peripheral neuropathy: A multicenter, randomized, double-blind, controlled trial. J Diabetes Investig. Campone M, Berton-Rigaud D, Joly-Lobbedez F, et al.

A double-blind, randomized phase II study to evaluate the safety and efficacy of acetyl-L-carnitine in the prevention of sagopilone-induced peripheral neuropathy. Hershman DL, Unger JM, Crew KD, et al. Carnitine supplementation 50 mg per 2. This last report found that the depletion of carnitine was significantly more severe when epileptics were taking valproic acid together with other anti-seizure medications.

A double-blind, crossover study found that carnitine supplementation mg per 2. To date, the question of whether carnitine supplementation is beneficial for people taking valproic acid remains unresolved. However, a panel of pediatric neurologists and experts on L-carnitine supplementation strongly recommended oral L-carnitine supplementation for all infants and children taking valproic acid, as well as for adults with carnitine deficiency syndromes, people with valproic acid-induced liver and kidney toxicity, people on kidney dialysis, and premature infants on total parenteral nutrition intravenous feeding.

The panel recommended an amount of mg per 2. Giovannini M, Agostoni C, Salari PC. Is carnitine essential in children? J Int Med Res ; Kobayashi A, Masumura Y, Yamazaki N. L-carnitine treatment for congestive heart failure—experimental and clinical study. Jpn Circ J ; Kendler BS. Carnitine: an overview of its role in preventive medicine.

Prev Med ; Tamamogullari N, Silig Y, Icagasioglu S, Atalay A. Carnitine deficiency in diabetes mellitus complications. J Diabetes Complications ; Learn more about TraceGains, the company.

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Home Health Information Library L-Carnitine. Uses L-carnitine is made in the body from the amino acids lysine and methionine , and is needed to release energy from fat. What Are Star Ratings? This supplement has been used in connection with the following health conditions: Used for Why 3 Stars.

Supplementing with L-carnitine may improve heart function and ease angina symptoms. Supplementing with L-carnitine can improve heart function and exercise capacity and reduce heart muscle damage due to insufficient oxygen.

Taking L-carnitine may help reduce damage and complications following a heart attack. is an amino acid important for transporting fats that can be turned into energy in the heart.

Clinical trials have reported that taking L-carnitine 4—6 grams per day increases the chance of surviving a heart attack. In one double-blind trial, individuals with suspected heart attack were given 2 grams of L-carnitine per day for 28 days.

At the completion of this study, infarct size, as well as the number of nonfatal heart attacks, was lower in the group receiving L-carnitine versus the placebo group.

Double-blind research using L-carnitine intravenously also shows promise. In double-blind trials, supplementing with either L-carnitine or propionyl-L-carnitine a form of L-carnitine has increased walking distance in people with intermittent claudication.

In double-blind trials, supplementation with L-carnitine and propionyl-L-carnitine a form of L-carnitine has increased walking distance in people with intermitting claudication. In the study using propionyl-L-carnitine, improvement occurred on in the those who could not walk meters to begin with.

The amino acid L-carnitine is thought to be potentially helpful for weight loss because of its role in fat metabolism. L-carnitine has been found to reduce fatigue and hunger and improve weight loss effects of fasting. Multiple controlled trials and three meta-analyses have shown that supplementing with L-carnitine can lead to small reductions in body weight in people with overweight and obesity.

In a placebo-controlled trial that included 60 overweight women with polycystic ovary syndrome, taking mg of L-carnitine daily for 12 weeks resulted in weight loss, waist circumference reduction, and improved glucose regulation and insulin sensitivity.

In a double-blind trial, supplementing with L-carnitine resulted in a modest improvement in disease severity in children with autism spectrum disorders. The amount of L-carnitine used was 50 mg per kilogram of body weight per day half in the morning and half in the evening for three months.

L-carnitine is an important nutrient for energy production. Supplementation can make up for a possible deficiency. Studies have shown that when L-carnitine is given to people with chronic lung disease, breathing during exercise improves.

In one study, supplementing with the combination of propionyl-L-carnitine a form of L-carnitine and acetyl-L-carnitine significantly improved erectile function in elderly men. L-carnitine has been found in some, but not all, clinical trials to reduce high cholesterol levels. is needed by cells, including heart muscle cells, to metabolize fat into energy, and numerous clinical trials show L-carnitine helps regulate cholesterol levels.

A meta-analysis that included findings from 67 randomized controlled trials found L-carnitine appeared to lower total and LDL-cholesterol, increase HDL-cholesterol, and reduce triglyceride levels; however, these benefits disappeared when age, health status, and other parameters of trials and their participants were considered.

Another meta-analysis that included 55 randomized controlled trials found only doses of L-carnitine higher than 2 grams per day improved total, LDL-, and HDL-cholesterol levels.

Using results from eight randomized controlled trials in a combined total of participants with type 2 diabetes, another meta-analysis found L-carnitine supplementation, at doses of 2—3 grams per day for at least 12 weeks, lowered total and LDL-cholesterol levels.

Supplementing with L-carnitine may help normalize triglyceride levels. In double-blind trials, supplementation with either L-carnitine or propionyl-L-carnitine a form of L-carnitine has increased walking distance in people with intermittent claudication.

L-carnitine appears to be necessary for normal functioning of sperm cells. Supplementing with it may improve sperm motility. L-carnitine supplementation may reduce cardiovascular risk by improving metabolic parameters such as body weight, blood glucose control, insulin sensitivity, and lipid levels.

The amino acid L-carnitine has been shown in clinical trials and meta-analyses to improve blood glucose control, insulin sensitivity, weight loss, and lipid metabolism, indicating its potential usefulness in treating metabolic syndrome and reducing cardiovascular risk.

In one placebo-controlled trial, women with obesity and type 2 diabetes participated in a low-calorie diet program and received 2 grams of L-carnitine per day or placebo for about eight weeks.

At the end of the trial, those receiving L-carnitine had greater improvements in blood glucose control, insulin sensitivity, cholesterol and triglyceride levels. In an uncontrolled trial, taking 3 grams of L-carnitine daily for three months led to decreased insulin resistance, LDL-cholesterol levels, and body-mass index BMI , and increased HDL-cholesterol levels in 80 women with polycystic ovary syndrome, a condition associated with metabolic syndrome.

In a study of children with sickle cell anemia, supplementing with L-carnitine reduced the number of painful crises and improved abnormal heart function and pulmonary hypertension. One trial showed that people who take L-carnitine for three weeks before engaging in an exercise regimen are less likely to experience muscle soreness.

Studies have shown that propionyl-L-carnitine a form of L-carnitine protects red blood cells of people with thalassemia against free radical damage. Supplementing with it may reduce the need for blood transfusions.

Supplementing with acetyl l-carnitine may reduce symptoms of diabetic neuropathy in people with type 1 diabetes. Acetyl l-carnitine is an amino acid compound used to treat conditions affecting the brain and peripheral nervous system.

Research reviews have concluded acetyl l-carnitine, in doses of at least 2 grams per day, can relieve pain and improve nerve function in those with diabetic nerve damage neuropathy. A preliminary trial found mg of acetyl l-carnitine three times daily for 24 weeks relieved symptoms of diabetic nerve damage neuropathy as effectively as vitamin B Supplementing with L-carnitine may reduce glucose, cholesterol, and triglyceride levels, and support medical therapies for type 2 diabetes.

L-carnitine is an amino acid needed to properly utilize fat for energy. By supporting healthy fat metabolism, L-carnitine plays an important role in preserving normal insulin sensitivity and glycemic control.

People with type 2 diabetes have been found to have lower levels of circulating L-carnitine than healthy people, and in people with type 2 diabetes, lower blood L-carnitine levels are correlated with higher blood glucose and triglyceride levels, lower free radical-quenching capacity, and greater risk of diabetes complications.

Supplementing with L-carnitine has been shown in multiple human and animal studies to improve glucose tolerance and lipid metabolism in the context of insulin resistance.

A meta-analysis of randomized controlled trials concluded 2—4 grams of L-carnitine per day can effectively reduce fasting blood glucose, total cholesterol, and LDL-cholesterol levels.

Clinical trials further show the potential for 2—4 grams of L-carnitine per day to augment other therapies for improving metabolism in people with diabetes, including glimepiride, orlistat, sibutramine, simvastatin, and a low-calorie diet.

In addition, a placebo-controlled trial found mg per day of L-carnitine alleviated diabetes-related muscle cramps a form of diabetic neuropathy in people with type 2 diabetes.

In a double-blind trial, supplementing with L-carnitine improved lung function and overall asthma control, compared with a placebo, in children with asthma. In a double-blind trial, supplementing with L-carnitine 1, mg each morning for six months improved lung function and overall asthma control, compared with a placebo, in Egyptian children with asthma.

L-carnitine has been popular as a potential aid in improving athletic performance because of its role in converting fat to energy. Some studies have found that it improves certain measures of muscle physiology. Inherited forms of cardiomyopathy seen in children may be responsive to L-carnitine.

L-carnitine injections have been used to improve circulation to the liver in people with cirrhosis. In one report, deficient levels of L-carnitine were found in five people with MVP. One person was given L-carnitine and experienced a complete resolution of MVP symptoms.

How It Works How to Use It Most people do not need carnitine supplements. Where to Find It Dairy and red meat contain the greatest amounts of carnitine.

Possible Deficiencies Carnitine deficiencies are rare, even in strict vegetarians , because the body produces carnitine relatively easily. Best Form to Take Derivatives of L-carnitine, specifically propionyl-L-carnitine and acetyl-L-carnitine, are available in supplement form, and have been used in some studies.

Interactions with Medicines Certain medicines interact with this supplement. What Are Drug Interactions. Types of interactions: Beneficial Adverse Check. Replenish Depleted Nutrients AZT Preliminary information suggests that muscle damage sometimes caused by AZT is at least partially due to depletion of carnitine in the muscles by the drug.

Learn More. In a case report, a woman developed visual disturbances and abnormal brain function, in association with subnormal blood levels of carnitine, after treatment with cefditoren pivoxil.

The abnormalities resolved after supplementation with L-carnitine. People taking cefditoren pivoxil should ask their doctor whether taking an L-carnitine supplement is appropriate. One controlled study showed that taking phenobarbital resulted in reduced blood levels of L-carnitine. Based on the currently available information, some healthcare practitioners may recommend monitoring L-carnitine blood levels or supplementing with L-carnitine.

Reduce Side Effects Abiraterone Acetyl-L-carnitine in the amount of 1, mg three times per day for eight weeks has been shown to improve nerve damage neuropathy caused by the chemotherapy drug cisplatin.

In a randomized trial, patients with chronic hepatitis C who were being treated with Peg-interferon-alpha 2b and ribavirin were randomly assigned to receive L-carnitine 2 grams twice a day or no L-carnitine control group. Compared with the control group, fewer patients in the L-carnitine group had to reduce the medication dosage or discontinue treatment because of side effects such as anemia or a decline in the white blood cell count.

Some drugs used to treat tuberculosis including isoniazid, rifampin, and pyrazinamide may cause liver damage. Support Medicine none. Reduces Effectiveness none. Potential Negative Interaction none.

Explanation Required Allopurinol People who have Duchenne muscular dystrophy have low levels of L-carnitine in their muscles. The Drug-Nutrient Interactions table may not include every possible interaction.

Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.

Side Effects Side Effects At the time of writing, there were no well-known side effects caused by this supplement. Related Information. Top Supplements for Heart Health Cardiovascular Disease Overview.

References 1. Dipalma JR. Carnitine deficiency.