By Summer Banks on Jul 05, 2017

Have you ever wondered about l-carnitine benefits like weight-loss or heart health?

Many people turn to dietary supplements, like l-carnitine, to gain lean muscle mass, lose weight or treat a specific medical condition. After all, there are dozens of products available to address different needs.

L-carnitine is one of 22 different amino acids.

It is in some foods but is not considered one of the eight essential amino acids. These include tryptophan, l-lysine, phenylalanine, methionine, leucine, isoleucine, valine and threonine.

Here we take a close look at l-carnitine benefits, how it impacts the body, where it comes from and the scientific research that is presented on this amino acid.

l carnitine amino acid

What is L-Carnitine?

To begin with, l-carnitine is an amino acid, which is a building block of protein. It is sometimes referred to as 3-hydroxy-4-N-trimethylaminobutyrate or 3-carboxy-2-hydroxy-N, N, N-trimethyl-1-propanaminium inner salt.


This amino acid is primarily found in red meat. However, you can also get it from food sources such as seafood, pork, chicken, cheese and milk, but the content levels are much lower. L-carnitine comes from animal sources. What about vegans and vegetarians?

Vegans and vegetarians use l-carnitine supplements to maintain adequate levels within the body.

It helps the body with converting fat into energy, which could account for l-carnitine weight-loss benefits. More specifically, it transports fatty acids into the cell’s mitochondria. The mitochondria is the “cell powerhouse” – vital for the production of energy in the presence of oxygen.

It’s critical in energy production in the presence of oxygen.

This substance is naturally produced by the human body. It is important for muscle movement, as well as brain and heart function.

L-carnitine is sometimes used to treat health conditions such as kidney disease, inflammation, male infertility, hyperthyroidism, chest pain and even heart failure.

Bottom Line: L-carnitine is an amino acid that is found in some animal products and supplements.

Different Types of Carnitine

Yes, there are different types of carnitine. Aside from l-carnitine, here are a few others.

L-carnitine l-tartrate

An amino acid used in many fitness supplements. It may help with faster recovery after workouts and reduce muscle soreness. This form absorbs easily and may help elevate energy levels for exercising.


Another amino acid sometimes used to treat high blood pressure and vascular disease. It has been shown to help improve blood flow and is sometimes used to treat congestive heart failure, angina, and PVD diseases. This form is not available in the United States but can be acquired in Europe.


This amino acid is also referred to as ALCAR. It’s been shown to be effective for treating brain and memory problems. This includes Alzheimer’s disease.

There are also many supplements claiming l-carnitine benefits like Max Muscle Max L-Carnitine.

Bottom Line: There are a few different variations of carnitine, which include l-carnitine l-tartrate, propionyl-l-carnitine, and acetyl-l-carnitine. All of which offer some health benefits.

How Much L-Carnitine Do You Need?

The amount needed for l-carnitine benefits just depends on your health and fitness goals. In general, most adults require 1-3 grams per day. However, this dosage may be adjusted to treat certain health conditions. Many people receive enough of this amino acid from dietary choices.

If you are taking l-carnitine for a health issue, such as hyperthyroidism, erectile dysfunction, Alzheimer’s disease, obesity or peripheral vascular disease, be sure to consult a licensed physician before getting started. He or she can recommend the correct dosage for you.

Taking too much can lead to side effects and health problems; thus, negating and l-carnitine benefits. Therefore it’s best to take dietary supplements by the instructions.

Bottom Line: Put simply, most people do not need more than 1-3 grams of l-carnitine per day. Unless otherwise directed by a doctor, it’s prudent to keep your dosage under three grams.

The Brain and Male Performance

L-Carnitine Benefits in the Body and Brain

Some documented research has shown that l-carnitine benefits include positive effects on the body and brain.

Some clinical studies have shown that this amino acid can help improve brain functionality, and may help treat certain types of dementia.


Other research has revealed that l-carnitine benefits include antioxidant and anti-inflammatory effects by combating harmful free radicals and slowing down mental deterioration.

This amino acid may also improve physical performance and elevate endurance levels for exercise.

For instance, one study involving 26 professional football players showed that consuming 3-4 grams of l-carnitine daily can improve endurance levels, elevate performance and prolong physical activity before exhaustion occurs.

Another study showed that taking an l-carnitine supplement in combination with antioxidants can help improve exercise performance to some degree.

Bottom Line: This amino acid may help improve physical endurance and overall performance, while preventing mental deterioration and memory loss.

What About L-Carnitine Weight-Loss?

There is some research that suggests l-carnitine weight-loss is possible. This is why this amino acid is often used in dietary supplements for weight reduction.

For starters, some studies have revealed that l-carnitine assists with lipid oxidation and converting fat into energy, while preserving lean muscle tissue. This way the body can keep the muscle mass while shedding excess fatty tissue.

Further research has demonstrated that l-carnitine supplementation can improve fat oxidation in slightly overweight adults. One study was conducted involving 12 volunteers taking three grams of l-carnitine for ten consecutive days.

(L-)carnitine meta-analysis may help bolster the claim for a weight loss aid. It is a recently published review of 9 studies from 2000-2013 (all foreign) that demonstrated that subjects had significant reduction in weight and BMI.

Bottom Line: Some research has demonstrated the potential effects of l-carnitine on weight-loss, but other studies have revealed that this amino acid does not speed up the fat loss process. Therefore more clinical research is needed.

l carnitine benefits and depression

Other L-Carnitine Benefits

According to some published research, other l-carnitine benefits are possible. For instance, this amino acid may help treat diabetes, erectile dysfunction, heart attack, chronic fatigue syndrome, neuropathic pain and even depression.

For example, one study showed that acetyl-l-carnitine might help treat patients with clinical depression.


Other research demonstrated that this amino acid has an analgesic effect and may help treat neuropathic pain by “improving the function of peripheral nerves and increasing nerve conduction velocity.”

Moreover, taking an l-carnitine supplement after having a heart attack may help minimize damage and complications.

In regards to diabetes, this amino acid has been shown to improve insulin sensitivity in insulin-resistant diabetic patients. It also helps the body utilize glucose as a source of fuel, more quickly.

Another study from the 2010 issue of Nutrition and Metabolism revealed that l-carnitine helps improve cardiovascular conditions, which in turn can help enhance glucose intolerance. This can be beneficial to people with diabetes.

Other research has shown that this amino acid “improves pain, nerve regeneration and vibratory perception in those with chronic diabetic neuropathy.”

Bottom Line: It is clear that there are additional l-carnitine benefits, some of which include treating diabetes, depression, neuropathic pain, and cardiovascular issues.

Are There Any L-Carnitine Side Effects?

Side effects can occur if too much l-carnitine is consumed.

These adverse reactions may include nausea, vomiting, diarrhea, upset stomach, heartburn, high blood pressure, headache and abdominal cramping.

However, more severe side effects or allergic reactions rarely occur in some individuals. These include fast heartbeat, seizures, impaired vision, muscle weakness, dizziness, weight-loss, tingling sensation, swelling in hands and feet, depression and fever.

There is one study that linked the l-carnitine in red meat to heart disease. This research also encouraged people to think before taking any l-carnitine supplements.

On a separate note, consuming too much of this amino acid can leave you smelling fishy.

Bottom Line: Put plainly, there are some mild side effects that can occur when too much l-carnitine is consumed. If you have a seizure disorder, Alzheimer’s disease or kidney disease, it is recommended that you speak with a licensed doctor before taking any l-carnitine supplements.

The Bottom Line on L-Carnitine Benefits

All in all, this is an important amino acid that does provide various l-carnitine benefits. Especially when it is received from foods and taken in healthy doses.

This component is especially important for converting the fat you consume into useful energy for daily activities and exercise.

If you make the decision to work toward l-carnitine weight-loss, physical fitness or some other health concern, it is wise to speak with your doctor beforehand. He or she can evaluate your overall health, and help you better determine the correct dosage for you and your individual needs.

Literature varies regarding the efficacy of l-carnitine and its proposed benefits. Prescription l-carnitine is FDA approved for l-carnitine deficiency, not as an over the counter dietary supplement.

Potential side effects are relatively mild, but it is still important to consult your primary care physician prior to starting any supplements.


“Metabolic Diseases of Muscle – Carnitine deficiency.” Muscular Dystrophy Association. January 18, 2016. Accessed June 14, 2017.

Colbert, Treacy. “L-Carnitine: Weight Loss Fact or Fiction?” Healthline. September 09, 2014. Accessed June 21, 2017.

“L-Carnitine.” Linus Pauling Institute. May 24, 2017. Accessed July 2, 2017. “L-Carnitine – Scientific Review on Usage, Dosage, Side Effects.” April 29, 2017. Accessed June 22, 2017.

“L-CARNITINE: User ratings for effectiveness, side effects, safety and interactions – WebMD.” WebMD. Accessed July 02, 2017.

“Metabolic Diseases of Muscle – Carnitine deficiency.” Muscular Dystrophy Association. January 18, 2016. Accessed June 14, 2017.

“Office of Dietary Supplements – Carnitine.” NIH Office of Dietary Supplements. Accessed July 3, 2017.

The effect of (L-)carnitine on weight loss in adults: a systematic review and meta-analysis of randomized controlled trials.” Obesity Reviews. Accessed July 10, 2017. doi: 10.1111/obr.12436.

“Protective role of CoQ10 or L-carnitine on the integrity of the myocardium in doxorubicin induced toxicity.” Tissue and Cell. Accessed July 9, 2017. doi: 10.1111/obr.12436.

L-Carnitine Benefits: Weight Loss, Heart Health and More

What is D carnitine?

D-Carnitine is an analog of L-carnitine that inhibits the uptake of L-carnitine by cells, in the range of 0.25-1 mM. L-Carnitine is an essential metabolite that transports a long-chain of fatty acids in the mitochondrial matrix for β-oxidation.

Can you take L carnitine and acetyl L carnitine together?

Yes, you can take these two forms of the amino acid L-carnitine together without risk. Acetyl L-Carnitine and L-Carnitine should be taken at different times but can definitely be taken on the same day. You should take L-Carnitine on an empty stomach.

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What is L carnitine fumarate used for?

L-carnitine fumarate is primarily a shuttle for fatty acids. It transports them across mitochondrial membranes into the mitochondria, where they are used for the production of energy.

What are the side effects of L carnitine?

Nausea, stomach upset, diarrhea, heartburn, and seizures are some side effects of L carnitine. It can also cause a “fishy odor” to the urine, breath, and sweat. Besides that, L-carnitine is LIKELY SAFE for most people when used as injection and when taken by mouth, with the approval of a healthcare provider

What is acetyl L carnitine used for?

Acetyl-L- carnitine helps the body produce energy. It is used for a variety of mental disorders including age-related memory loss, like Alzheimer’s disease, thinking problems related to Lyme disease, thinking problems related to alcoholism, and late-life depression.

What is Acetyl l carnitine for?

Acetyl-L-carnitine, ALCAR or ALC, is an acetylated form of L-carnitine. Although it is often taken as a dietary supplement, it is naturally produced by the body.

How long does it take for acetyl L carnitine to work? .

As soon as it enters the bloodstream is when Acetyl L-Carnitine starts to work. 15 to 30 minutes after consumption is typically how long it takes.

How much l carnitine should you take a day?

Dosage varies from study to study but here’s an overview of the use and dose of each form: The form L-Carnitine L-Tartrate is most effective for exercise performance. The form Acetyl-L-Carnitine is best for function and brain health. Doses vary from 600–2,500 mg per day.

What foods are high in acetyl L carnitine?

At about 56-162 mg per serving, red meat is one of the highest sources of L-carnitine. It can also be found at much lower levels, between 3 and 7 mg per serving, in foods like seafood, pork, and chicken. There are 3 and 8 mg per serving in dairy like milk and cheese, and ice cream.

How does carnitine work in the body?

L-carnitine plays an important role in your body. It escorts long-chain fatty acids to your cells’ mitochondria, where they produce energy. It is stored in your brain, heart, and skeletal muscles.

What is carnitine?

In energy production, Carnitine plays a critical role. It is derived from an amino acid. Long-chain of fatty acids are transported by carnitine into the mitochondria so they can be oxidized to produce energy. In nearly all cells of the body, it is found.

What is the meaning of carnitine?

L-Carnitine, an endogenous molecule, is involved in fatty acid metabolism, biosynthesized within the human body using amino acids: L-methionine and L-lysine as substrates.

What is L carnitine tartrate good for?

Typically, L-Carnitine is used for power output and physical performance. Acetyl-L-Carnitine (ALCAR) is used for enhanced cognitive function. Glycine Propionyl L-Carnitine (GPLC) is used for blood flow issues and to alleviate intermittent claudication.

What is carnitine used for?

You need l-carnitine if you want to use fat as a fuel as efficiently and effectively as possible. L-carnitine is the nutrient that shuttles fatty acids from the blood into the mitochondria. The energy-producing “furnaces” in the cells, so that the fatty acids can be used as energy.

Is carnitine an essential amino acid?

Technically carnitine, or L-carnitine, is not an amino acid. Actually, it is a dipeptide made from the amino acids L methionine and lysine. Therefore, it is often classified as a conditionally essential amino acid.

What is propionyl L carnitine?

In clinical settings, PLC (Propionyl L-Carnitine) is used to deliver direct assistance in the production of cardiovascular energy. Swanson GlycoCarn GPLC is a new dietary ingredient that provides a special form of carnitine used for heart health.

About the Author:

Summer Banks, Director of Content at Dietspotlight, has researched over 5000 weight-loss programs, pills, shakes and diet plans. Previously, she managed 15 supplement brands, worked with doctors specializing in weight loss and completed coursework in nutrition at Stanford University. full bio.