L-Carnitine

October 3, 2020

This article provides general nutrition information only and is not medical advice.

Overview

L-carnitine is an amino acid that is produced in the body. L-carnitine helps the body turn fat into energy. The body can convert L-carnitine to other amino acids called acetyl-L-carnitine and propionyl-L-carnitine. But, no one knows whether the benefits of these other carnitines are the same. Until more is known, don't switch one form of carnitine for another.

L-carnitine is taken by mouth to increase L-carnitine levels in people whose natural level of L-carnitine is too low. Some people also use L-carnitine for conditions of the heart and blood vessels, overactive thyroid, inability to become pregnant within a year of trying to conceive (infertility), serious kidney condition, and many other conditions, but there is no good scientific evidence to support these uses.

Classification

Is a Form of:

Amino Acid

Primary Functions:

To increase L-carnitine levels in the body

Also Known As:

3-carboxy-2-hydroxy-N,N,N-trimethyl-1-propanaminium inner salt, (3-carboxy2-hydroxypropyl) trimethylammonium hydroxide inner salt

How Does It Work?

L-carnitine helps the body produce energy. It is important for heart and brain function, muscle movement, and many other body processes.

Uses

Serious kidney condition. Most research suggests that taking L-carnitine by mouth or intravenously (by IV) can improve red blood cell counts during hemodialysis. The US Food and Drug Administration (FDA) has approved L-carnitine for the nutritional support and prevention of L-carnitine deficiency in people with serious kidney condition who are undergoing hemodialysis.
L-carnitine deficiency. The FDA has approved L-carnitine for treating L-carnitine deficiency caused by certain genetic conditions.
Chest pain (angina). Taking L-carnitine by mouth or intravenously (by IV) seems to improve exercise tolerance in people with chest pain. Taking L-carnitine along with standard nutritional support also seems to reduce chest pain and improve exercise ability in people with cardiac syndrome X. People with this condition have chest pain but not blocked arteries.
Heart failure and fluid build up in the body (congestive heart failure or CHF). Taking L-carnitine by mouth or intravenously (by IV) seems to improve concerns and increase exercise ability in people with heart failure. Taking a specific product containing L-carnitine and coenzyme Q10 also appears to improve concerns of heart failure.
Serious kidney condition (end-stage renal condition or ESRD). People in the last stage of long-term, serious kidney condition need to undergo hemodialysis, which can lower L-carnitine levels. The US Food and Drug Administration (FDA) has approved giving L-carnitine intravenously (by IV) but not by mouth to support and prevent L-carnitine deficiency in these patients. There is mixed evidence about the effects of L-carnitine in treating imbalances caused by low carnitine levels in people with serious kidney condition undergoing hemodialysis. Taking L-carnitine by mouth or giving L-carnitine intravenously might improve markers of anemia and physical strain in people with this condition. But L-carnitine does not seem to improve quality of life, muscle cramping, low cardiovascular health, breathing function, or exercise performance.
Overactive thyroid (hyperthyroidism). Taking L-carnitine seems to improve concerns such as rapid or pounding heartbeat, nervousness, and weakness in people with high thyroid hormone levels.
Conditions in a man that prevent him from getting a woman pregnant within a year of trying to conceive (male infertility). Most research shows that taking L-carnitine, alone or in combination with acetyl-L-carnitine, increases sperm count and sperm movement in men with fertility problems.
Swelling (physical strain) of the heart (myocarditis). Taking D,L-carnitine by mouth seems to reduce the risk of death from myocarditis.
A hormonal imbalance that causes enlarged ovaries with cysts (polycystic ovary syndrome or PCOS). Clomiphene is a medication used to help with ovulation. However, it doesn't work well in some women with PCOS. In these women, taking L-carnitine increases ovulation and the chance of getting pregnant. Also, taking L-carnitine might help with weight loss and improve blood sugar levels in these women.
Toxic side effects caused by the drug valproic acid. Toxicity caused by valproic acid seems to be linked with L-carnitine deficiency. Giving L-carnitine intravenously (by IV) can prevent severe liver toxicity in people who accidentally ingested or took too much valproic acid.

Recommended Dosing

The following doses have been studied in scientific research:

ADULTS

BY MOUTH:

For L-carnitine deficiency: 990 mg two to three times daily in tablets or as an oral solution.
For chest pain (angina): Doses of 900 mg to 2 grams of L-carnitine have been taken in one to two divided doses daily for 2 weeks to 6 months.
For heart failure and fluid build up in the body (congestive heart failure or CHF): 1.5 to 3.0 grams of L-carnitine has been taken in one to two divided doses daily for up to about 34 months. A specific product (Carni Q-Gel, Tishcon Corporation) containing 2250 mg of carnitine and 270 mg of coenzyme Q10 has been taken daily for 12 weeks.
For serious kidney condition (end-stage renal condition or ESRD): Doses of 0.64-3 grams or 10 mg/kg of L-carnitine has been used daily for 3-52 weeks. Taking L-carnitine by mouth is not FDA approved to support carnitine deficiency in people with serious kidney condition.
For overactive thyroid (hyperthyroidism): 2-4 grams of L-carnitine has been taken daily for 2-4 months.
For conditions in a man that prevent him from getting a woman pregnant within a year of trying to conceive (male infertility): 2-3 grams of L-carnitine has been taken in up to three divided doses daily, with or without vitamin E, for 2 to 24 weeks. Also, 2 grams of L-carnitine plus 1 gram of acetyl-L-carnitine has been taken daily, with or without a 300 mg cinnoxicam suppository every 4 days, for 3-6 months. A specific product (Proxeed Plus, Alfasigma USA) containing L-carnitine 1 gram and acetyl-L-carnitine 0.5 gram, with citric acid, zinc, coenzyme Q10, selenium, vitamin C, folic acid, and vitamin B12, twice daily for 6 months.
For swelling (physical strain) of the heart (myocarditis): 100 mg/kg of D,L-carnitine has been taken daily for 4 days.
For a hormonal imbalance that causes enlarged ovaries with cysts (polycystic ovary syndrome or PCOS): 250 mg of L-carnitine has been taken daily for 12 weeks. 3-4 grams of L-carnitine have been taken daily during clomiphene nutritional support starting at day 3 of the cycle and ending within 2-3 weeks. L-carnitine 3 grams daily for 3 months has also been used.
For toxic side effects caused by the drug valproic acid: 50 to 100 mg/kg has been taken in three or four divided doses daily up to a maximum of 3 grams daily.

INTRAVENOUS (IV):

For L-carnitine deficiency: Doses of 50 mg/kg of L-carnitine have been given as a slow injection or by infusion followed by 50 mg/kg of L-carnitine in divided doses every 3 to 4 hours over the next 24 hours. In the following days, daily maintenance doses are usually in the range of 50 mg/kg. For people with L-carnitine deficiency related to hemodialysis, 10 to 20 mg/kg of L-carnitine adjusted for L-carnitine blood levels is used.
For chest pain (angina): An infusion of 3 grams of L-carnitine in 500 mL of 5% dextrose has been given once daily for 14 days. 40mg/kg of D-L-carnitine has also been given by IV 30 minutes before exercise.
For heart failure and fluid build up in the body (congestive heart failure or CHF): 5 grams of L-carnitine has been given by IV daily for 7 days in addition to conventional nutritional support.
For serious kidney condition (end-stage renal condition or ESRD): Doses of 10 to 20 mg/kg of L-carnitine given as a slow injection is FDA-approved for use for L-carnitine deficiency in people with serious kidney condition. For treating imbalances related to low levels of carnitine in hemodialysis patients, 1.8 grams of L-carnitine weekly to 3 grams daily or 30-120 mg/kg/week have been given by IV for 2 weeks to 12 months. Doses were usually given three times weekly after dialysis sessions. Also, 1 gram of L-carnitine has been given by IV three times weekly after each dialysis session together with 100 mg of coenzyme Q10 taken by mouth daily for 3 months.
For toxic side effects caused by the drug valproic acid: 150-500 mg/kg/day up to 3 grams/day has been used

L-Carnitine Supplements Frequently Asked Questions

What is L carnitine used for?

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.

Does L carnitine help you lose weight?

L-carnitine is best known as a fat burner — but the overall research is mixed. It is unlikely to cause significant weight loss. However, studies support its use for health, brain function and condition prevention. Noom helps you adopt healthy habits so you can lose weight and keep it off.

Does L carnitine have side effects?

When taken by mouth: L-carnitine is LIKELY SAFE when taken for up to 12 months. It can cause side effects such as nausea, vomiting, stomach upset, heartburn, diarrhea, and seizures. It can also cause the urine, breath, and sweat to have a "fishy" odor.

Is L carnitine good for the heart?

Mayo Clinic review links L-Carnitine to multiple heart health benefits. A systematic review by the Mayo Clinic has said that L-Carnitine can reduce mortality, abnormal heart rhythms and angina development in patients experiencing a heart attack.

Does L carnitine make you poop?

It has quite a laxative effect (that means it makes you poop soup!) until your body re-learns to release whatever enzyme bonds to this stuff.

Does L carnitine raise cardiovascular health?

A small study published in the journal Hypertension in July showed that taking 2 grams of acetyl-L-carnitine twice a day appeared to lower cardiovascular health and improve insulin resistance in 32 patients identified as at risk for diabetes and cardiovascular condition.

What foods contain L carnitine?

Red meat has the highest levels. A 4-ounce beef steak has an estimated 56 mg to 162 mg of carnitine. Carnitine is also found in smaller amounts in chicken, milk and dairy products, fish, beans, and avocado. Vegans tend to get less carnitine from foods, but their bodies usually produce enough anyway.

Is carnitine good for kidneys?

L-carnitine is an essential compound that facilitates the transport of long-chain fatty acid across the inner mitochondrial membrane for β-oxidation. However, the effect of L-carnitine supplementation remains to be fully explored in patients with chronic kidney condition.

Does L carnitine make you smell like fish?

L-carnitine is LIKELY SAFE when taken by mouth for up to 12 months, and when used as an injection, with the approval of a healthcare provider. It can cause side effects such as nausea, vomiting, stomach upset, heartburn, diarrhea, and seizures. It can also cause the urine, breath, and sweat to have a "fishy" odor.

Should I take L carnitine on an empty stomach?

However, at first glance it appears that carnitine will face stiff competition from amino acids for absorption through ATB^0,+ in the fed intestine, particularly in more proximal regions. Carnitine supplements are therefore likely to be much better absorbed on an empty stomach!

Does CLA burn fat?

Research in humans shows that CLA has only a modest weight loss benefit. One review of these studies evaluated its long-term effectiveness on fat loss in overweight and obese participants. It concluded that taking 2.4–6 grams per day for 6–12 months reduced body fat by 2.93 lbs (1.33 kg), compared to placebo ( 20 ).

Does carnitine make you sweat?

It can cause side effects such as nausea, vomiting, stomach upset, heartburn, diarrhea, and seizures. It can also cause the urine, breath, and sweat to have a "fishy" odor. ... These forms of carnitine might block the effects of L-carnitine and cause concerns that resemble L-carnitine deficiency.

Does carnitine cause pimples?

L-Carnitine, a Natural Non-Cystic Acne Remedy. L-Carnitine is an amino acid that helps enhance the metabolism of fats and oils, which ultimately reduces excess sebum produced by the skin. Less sebum means less food for acne-causing bacteria, which means less acne.

How much weight can you lose with L carnitine?

Because L-carnitine can be absorbed quickly into the body, especially when it's consumed in liquid form, the best time to take is in the morning and/or prior to workouts. It is recommended that you take between 2-4g of L-carnitine per day, divided into two or three evenly split dosages.

Is L carnitine safe for the liver?

NEW YORK (Reuters Health) – L-carnitine supplements can improve liver function, liver histology and other manifestations of nonalcoholic steatohepatitis (NASH), Italian researchers say. On a scale of 1 to 4, fibrosis also improved significantly more in the L-carnitine group (mean change 1.31 vs 0.85, p < 0.05).

Does L carnitine burn belly fat?

In theory, using L-carnitine as a weight loss supplement makes sense. Since L-carnitine helps move more fatty acids into your cells to be burned for energy, you might think this would increase your ability to burn fat and lose weight.

What's the best time to take L carnitine?

Is L carnitine a blood thinner?

Taking L-carnitine supplements may prevent any deficiency and may also reduce the side effects of valproic acid. Blood Thinning Medications: Carnitine may increase the risk of bleeding in people taking blood thinning medicaitons.

Is L carnitine bad for your kidneys?

However, adverse effects are unlikely to occur with the routine doses (from 3 to >100 g/day). The risks and benefits of L-carnitine on the athletes' and bodybuilders' kidney have not been evaluated yet. However, L-carnitine up to 6000 mg/day is generally considered to be a safe supplement at least in healthy adults.

Should I take carnitine everyday?

In one review of L-carnitine's safety, doses of approximately 2 grams per day appeared to be safe for long-term use. However, there were some mild side effects, including nausea and stomach discomfort ( 24 , 58 ). However, L-carnitine supplements may raise your blood levels of trimethylamine-N-oxide (TMAO) over time.

How can I get L carnitine naturally?

Clinical Studies

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