15 Evidence-Based Benefits of L-Carnitine

If you are looking for an energy boost, a performance enhancer, or ways to prevent Alzheimer’s and other memory decline issues, look no further than carnitine.

If you are not familiar with this important amino acid, then we have you covered.

Carnitine can be found in many forms and is in many of the foods that you eat.

However, you may need more of this compound than you think and taking a supplement could improve your health.

Whether you have diabetes, genetic disorders, are overweight or suffer from chronic illness, carnitine may be able to improve your condition and help you feel better.

We will first explain what carnitine is, where it can be found in nature and how to take it correctly in supplement form.

We will then discuss the health benefits that carnitine can offer to your body and mind, including how it can help you lose weight and perform better athletically.

Finally, we will discuss the precautions for taking this supplement and the very rare adverse effects.


Understanding Carnitine

You may not even realize it, but carnitine is already in nearly all the cells in your body.

It is an amino acid that is part of many compounds, including propionyl-L-carnitine, acetyl-L-carnitine, and L-carnitine.

Amino acids are essential for your health since they are the building blocks of all proteins.

L-carnitine plays a vital role in energy production within the cells, because it transports fatty acids into the mitochondria, which are your cells’ engines (1).

They burn fats to produce energy that your body can use for various functions.

When sold as supplements, the various carnitine compounds are all different and have distinct health benefits.

For the purposes of this article, our focus is on  L-carnitine.

We will briefly look at the other two, so you understand the difference.

For example, the primary use of propionyl-L-carnitine is to improve blood circulation (2).

This compound is often used to treat leg pain from intermittent claudication, which is caused by poor circulation from peripheral vascular disease.

Acetyl-L-carnitine is made in the body from L-carnitine, and it is commonly used to treat various cognitive disorders (3).

It can be helpful for those with Alzheimer’s disease, other forms of dementia, depression, cognitive problems due to alcoholism and other difficulties with thinking that are caused by diseases or poor anatomical function.

There are also other forms of carnitine, including D-Carnitine, which is inactive but can inhibit the absorption of other forms of carnitine, creating a deficiency (4).

Another form of carnitine is L-Carnitine L-Tartrate, which is a specific time or L-carnitine that absorbs into the body rapidly and is commonly used by athletes to aid in recovery (5).

All forms of carnitine are important for producing energy in the body.

One of the primary functions of carnitine is to create energy from body fat, while also flushing wastes and toxins from your cells.

Your body naturally produces this amino acid in the kidneys and liver.

You store the excess carnitine in your heart and brain.

However, most of it is stored in muscle tissues (6).

Some disorders and conditions result in carnitine deficiency.

A primary carnitine deficiency results from a genetic disorder that usually manifests in early childhood.

A secondary carnitine deficiency occurs when disease or certain conditions are present.

For example, some vegetarians may not get enough carnitine from eating non-animal foods, and those with chronic renal failure are also at risk.

Your doctor can discuss whether your condition could cause a carnitine deficiency.


Sources of Carnitine

Most people get the carnitine they need from the foods they eat.

The most common sources of this amino acid in our diets are milk, dairy products, poultry, fish and meat.

In fact, animal products are the most reliable sources of L-carnitine for humans, and grass-fed beef has the highest concentration per serving.

Some vegetables and grains also have smaller amounts of this amino acid (7).

For those who do not eat animal products, or for anyone with a carnitine deficiency, you can also get this crucial amino acid by taking dietary supplements.

L-carnitine is available in several forms, including liquids, capsules and even injectables.

It is best to take these oral supplements with food to increase its effectiveness.

You can take anywhere between 500 and 2,000 milligrams per day of L-carnitine oral supplements with minimal side effects.

Other forms of carnitine will have different dosages, however, so check with your doctor and read all labels carefully when taking carnitine supplements.

You should start with lower dosages and gradually increase the amount over time, to see how you will tolerate this compound.


L-Carnitine’s Health Benefits

L-carnitine has been shown to have numerous benefits for both your physical health and mental well-being.

If you do not currently make enough carnitine or get sufficient amounts from your diet, then taking an L-carnitine supplement could help you treat and prevent a number of health conditions.

We will discuss the many advantages that this amino acid can bring to your life, according to the latest medical research.


Improved Weight Loss

Many people take L-carnitine to help improve their weight loss efforts.

This compound is best- suited for older adults who are trying to lose weight since they are more likely to have lower levels of this amino acid.

Since the function of L-carnitine in the body is to break down fat to be used for energy, it can be used to help you shed additional pounds, when you are exercising and eating well.

For example, one study of women with PCOS (polycystic ovary syndrome) found that those participants taking L-carnitine were able to lose more weight, improve their BMI and reduce their hip and waist circumference (8).

A meta-analysis of recent research on L-carnitine and weight loss shows that it is helpful in many cases where people are trying to lose weight (9).

Examining the results of nine separate studies, researchers found that supplemental L-carnitine resulted in a more substantial weight loss and a more significant reduction in body mass index compared to those not taking the supplement.

While these results are not seen in all users, it does seem to help some who are struggling to lose excess pounds.


Enhanced Athletic Performance

In addition to helping you to break down fats for energy usage, L-carnitine can also reduce the concentration of lactic acid in your muscles during exercise.

This results in faster recovery, less cellular damage and more athletic endurance (10).

Being able to work out longer and harder can also help you lose weight, as well as improve your athletic performance.

Athletes who take supplemental L-carnitine enjoy longer workouts with better recovery time.

One study noted increased time before professional soccer players reached exhaustion (11).

In addition, L-carnitine can help protect your muscles from damage caused by exercise.

In one study, athletes who took L-carnitine had lower levels of various markers that show muscle damage (12).


Boosts Brain Function

Certain forms of L-carnitine, especially acetyl-L-carnitine, play a crucial role in brain function, particularly memory.

For those with diseases that affect the memory, like dementia, carnitine deficiency is common.

Therefore, taking supplemental forms of this compound can help to slow the progression of these diseases (13).

When you take carnitine, your body produces acetylcholine, which is a neurotransmitter that is vital to memory function.

When you have sufficient levels of carnitine in your body, your brain cells get the energy they need to slow down memory loss and neurodegeneration (14).


Treatment and Prevention of Diabetes

One of the reasons that people develop diabetes over time, is that they become insulin resistant.

This means that their bodies are unable to use insulin as effectively as they should.

Insulin resistance is connected to your ability or efficiency in burning fat.

When you are insulin resistant, you are more likely to have elevated levels of fat in your lean muscle tissues.

By taking carnitine, some have experienced a decrease in fat, which results in higher insulin sensitivity (15).

This was also seen in PCOS patients (16).


Reduced Fatigue

Fatigue is a common side effect of many diseases and treatments, including cancer treatments.

Taking L-carnitine can help to prevent fatigue caused by chemotherapy, radiation therapy and even some diseases that cause fatigue.

By improving the quality of sleep, L-carnitine has been shown to reduce fatigue in terminal cancer patients, reducing fatigue and improving their quality of life (17).

Anemia is another leading cause of disease, since it prevents the sufficient supply of oxygen to the body’s muscles, organs and other tissues, resulting in fatigue.

Research has shown the L-carnitine can help to improve blood cell counts and function, which can improve energy levels and reduce fatigue over time (18).

Having higher red blood cell counts results in more oxygen in the blood, improved cell endurance and enhanced overall energy levels.

Fatigue is also a natural result of the aging process since many people often have less energy as they age.

By supplementing with L-carnitine, older adults have enjoyed less physical and mental fatigue, while also having a better cognitive function (19).


Protects the Heart

If your heart is weakened or if you have heart disease, L-carnitine can help to strengthen your heart and improve your chances of survival.

In addition to protecting heart function, this supplement can help your heart by correcting heart arrhythmia, improving blood flow and enhancing glucose metabolism, which gives your heart the energy it needs (20).

Those who are in heart failure can also improve their survival possibilities, by taking L-carnitine (21).

In animal trials, L-carnitine taken with taurine was shown to stop plaque accumulation and prevent the hardening of blood vessels that can lead to heart attacks, strokes and other types of heart disease (22).

When used in conjunction with traditional medical treatments, L-carnitine has improved angina symptoms and promoted a more regular heart rhythm (23).

There is some evidence to suggest that L-carnitine can even help those with congenital heart defects to improve blood flow and normalize heart rhythms (24).


Boosts Your Mood

Certain types of carnitine, particularly acetyl-L-carnitine, can help to improve symptoms of depression and enhance mood.

For those with age-related depression, this form of the amino acid has been shown to have an anti-depressant effect (25).

It is also helpful for those with certain chronic conditions that can lead to depression over time, like fibromyalgia and narcolepsy (26).


Improved Sleep Quality

Getting a good night’s sleep is vital for your overall health and well-being in many ways.

When you do not get enough sleep, or if you have sleep-disordered breathing, like sleep apnea, your heart can sustain damage over time (27).

Taking supplemental carnitine can improve sleep for those with sleep apnea, by improving airflow and increasing oxygen levels, which promote heart function.

Sleep disorders are common among those with mitochondrial disorders as well as the elderly.

Therefore, taking L-carnitine supplements can help to improve these symptoms in some patients (28).


Improved Male Fertility and Sexual Function

For men, having a carnitine deficiency can have a negative impact on fertility, as well as sexual function.

Sperm motility and the count is directly proportional to carnitine concentrations in the body, so for those suffering from these problems, supplemental carnitine could be helpful.

By reducing cell damage and death and providing sufficient energy to sperm cells, carnitine is able to supply these cells with what they need to increase fertility (29).

Taking supplemental carnitine has been shown to be as effective at improving sperm count and motility as more invasive treatments, including varicocelectomy surgery (30).

One theory for its effectiveness is that carnitine is an antioxidant, effecting destroying free radicals in the body.

Free radicals can build up because of many factors, including infection, environmental stimuli, and even sexual abstinence.

Having sufficient levels of this amino acid can help to destroy these harmful free radicals and improve cellular health (31).

One study also indicated that patients taking carnitine also had higher levels of testosterone, indicating that one of the effects of carnitine supplementation could be improved sexual function, which is dependent on sufficient levels of testosterone (32).


Treatment for HIV/AIDS

HIV, the virus that causes AIDS, can result in cellular degeneration, which can lead to significant symptoms and complication.

L-carnitine may be able to slow or even halt this degeneration, leading to improved outcomes for patients.

This can be accomplished by reducing cellular death, preventing tissue damage, lowering triglycerides, and increasing t-cell concentrations, which help to fight disease (33).

By preventing the death of white blood cells, L-carnitine can help to fight the HIV infection.

Those taking L-carnitine are more likely to have higher CD4 and CD8 cell counts, which are the white blood cells most beneficial in fighting HIV (34).


Enhanced Bone Strength

L-carnitine could become a possible future treatment option for osteoporosis.

Animal trials have shown that taking L-carnitine can stimulate bone formation and improve bone density and structure, all of which are affected by osteoporosis and other degenerative diseases (35).

This supplement can also enhance the mineral content and density of bones, which could benefit women in menopause (36).

This promotion of bone mineralization is partially due to the ability of L-carnitine to block the effects of various thyroid hormones (37).


Treatment for Leg Pain

Intermittent claudication is a disorder that leads to pain in the legs while walking or running, due to the poor blood supply.

Patients with this disorder often have pain in the hips, thighs, calves, and feet.

This pain can worsen with movement.

Taking carnitine, propionyl-L-carnitine or PLC, helped relieve leg pain and allowed patients to walk for longer periods than without the supplement (38).


Improved Liver Health

When you have low levels of carnitine, you can experience liver damage.

Certain drugs, such as anticonvulsants, reduce carnitine levels and often result in liver damage over time.

Taking supplemental L-carnitine can help to prevent this cellular damage and keep your liver healthy if you are taking these types of medications (39).

Those with hyperthyroidism who take certain medications are also vulnerable to liver damage, and taking L-carnitine can help to protect against this adverse effect (40).

This is due to its ability to fight free radical damage and to prevent oxidative stress.


Supports Skin Health

In addition to taking L-carnitine orally, this amino acid is also available as a topical treatment which can help improve your skin.

Topical carnitine treatments can decrease oil production by pores and improve skin texture and appearance.

Participants in one study who used topical carnitine experienced less oily skin, a smoother skin appearance and overall better skin health (41).


Protects Against Hyperthyroidism

If you have an overactive thyroid, it is important that you have sufficient levels of L-carnitine (42).

By inhibiting the entry of the T3 (triiodothyronine) and T4 (thyroxine) hormones into cells, L-carnitine can help reduce the effects of an overactive thyroid.

Taking up to 2,000 milligrams of L-carnitine has been shown to help protect again hyperthyroidism (43).


Other Benefits of L-Carnitine

In addition to these benefits, L-carnitine has also been shown by recent research to be helpful in other areas.

These include:

  • Increasing the lifespan and suppressing the onset of neuromuscular degeneration for patients with ALS or amyotrophic lateral sclerosis (44).
  • Protecting against possible genetic damage from chemicals, such as diazinon, a powerful insecticide (45).
  • Reduce episodes of daytime sleepiness and dozing for patients with narcolepsy, by increasing levels of serum acylcarnitine and reducing lipids in the blood (46).
  • Suppressing seizures, which could lead to the use of this supplement as a possible treatment for epilepsy and other seizure disorders (47).
  • Improving kidney function in those with chronic kidney disease, by lowering levels of BUN and creatinine in the blood (48).


Precautions and Interactions

It is important that you not exceed the recommended daily dose of L-carnitine supplements.

Dosages of three grams or more have been shown to cause nausea, vomiting, diarrhea and abdominal cramps (49).

In rare incidences, high doses have led to muscle weakness and seizures, especially in those prone to heart disease or who have a seizure disorder.

Some have reported rashes and an unexplained increase in appetite after taking L-carnitine.

If you have hypothyroidism, you should not take L-carnitine supplements.

This amino acid can interfere with the cellular entry of both triiodothyronine (T3) and thyroxine (T4), which are thyroid hormones.

In animal trials, the long-term use of L-carnitine has been linked to liver and kidney problems, so it is best to only use this supplement for short durations (50).

If you have diabetes, kidney disease, high blood pressure, or cirrhosis, you should talk with your doctor before taking L-carnitine.

The most common recommendation is not to exceed 1,000 milligrams per day of L-carnitine oral supplements.

If you want to take more, you should consult with your physician first.

It is always advisable that you talk with a healthcare professional before taking any dietary supplements.



L-carnitine is an amino acid that is vital to the health and longevity of your body’s cells.

Your body naturally makes its own carnitine.

Many people get sufficient amounts of this compound from the foods they eat, mainly from animal sources like meat and dairy products.

If you have a deficiency of carnitine, however, you can experience some significant health problems.

This is because it is necessary for converting fatty acids in the body into energy for your cells to use.

If you are deficient in carnitine, you should consider taking a dietary supplement.

L-carnitine can help improve your energy level, athletic performance, sleep quality and mood.

It can also help your heart and brain stay healthy and function properly.

Taking L-carnitine can also help with your weight loss efforts.

Having enough L-carnitine in your system keeps your liver healthy and can help you fight diseases like dementia, ALS, kidney disease, HIV, hyperthyroidism, and osteoporosis.

Men with fertility issues may also benefit from taking L-carnitine.

This supplement is generally considered to be safe with few adverse effects.

The most common side effects of taking this amino acid are nausea, vomiting, and diarrhea.

When it is used in conjunction with exercise and healthy eating, it can help you lose weight.

It is also an excellent complement to traditional therapies and treatments for many disorders and diseases.

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