What is L-Carnitine? Wait, what is an Amino Acid?
L-carnitine is an amino acid produced by the body thatโs also found in food and supplements. Some studies suggest it may offer some health benefits, including increased weight loss, improved brain function, and more.
Amino acids are the building blocks of protein. Proteins are long chains of amino acids. Your body has thousands of different proteins that each have important jobs. Each protein has its own sequence of amino acids. The sequence makes the protein take different shapes and have different functions in your body.
You can think of amino acids like the letters of the alphabet. When you combine letters in various ways, you make different words. The same goes for amino acids โ when you combine them in various ways, you make different proteins.
What is L-carnitine?
L-carnitine is a nutrient and dietary supplement. It plays a crucial role in the production of energy by transporting fatty acids into your cellsโ mitochondria (1Trusted Source).
The mitochondria act as engines within your cells, burning these fats to create usable energy. Your body can produce L-carnitine out of the amino acids lysine and methionine (2Trusted Source).
For your body to produce it in sufficient amounts, you also need plenty of vitamin C (3Trusted Source).
In addition to the L-carnitine produced in your body, you can also obtain small amounts by eating animal products like meat or dairy products (2Trusted Source).
Vegans or people with certain genetic issues may be unable to produce or obtain enough. This makes L-carnitine a conditionally essential nutrient (2Trusted Source).
Different types
L-carnitine is the standard biologically active form of carnitine, which is found in your body, foods, and most supplements.
Here are several other types of carnitine:
- D-carnitine: This inactive form has been shown to reduce blood levels of carnitine and increase fat buildup, leading to liver inflammation and oxidative stress (4Trusted Source).
- Acetyl-L-carnitine: Often called ALCAR, this is possibly the most effective form for your brain. Studies suggest that it may benefit people with neurodegenerative diseases (5Trusted Source).
- Propionyl-L-carnitine: This form is well-suited for circulatory issues, such as peripheral vascular disease and high blood pressure. According to some older research, it may boost the production of nitric oxide, which improves blood flow (6Trusted Source, 7Trusted Source).
- L-carnitine L-tartrate: This is commonly added to sports supplements due to its rapid absorption rate. It may aid muscle soreness and recovery in exercise (8Trusted Source, 9Trusted Source).
For most people, acetyl-L-carnitine and L-carnitine seem to be the most effective for general use. However, you should always pick the form thatโs best for your personal needs and goals.
Role in your body
L-carnitineโs main role in your body involves mitochondrial function and energy production (1Trusted Source).
In cells, it helps transport fatty acids into the mitochondria, where they can be burned for energy.
More than 95% of your L-carnitine stores are contained in your muscles, along with trace amounts in your blood, liver, heart, and kidneys.
L-carnitine may help increase mitochondrial function, which plays a key role in disease and healthy aging.
Newer research illustrates the potential benefits of carnitineโs different forms, which may be used for various conditions, including heart and brain diseases.
SUMMARY
L-carnitine is an amino acid derivative that transports fatty acids into your cells to be processed for energy. It is made by your body and also available as a supplement.
Does it aid weight loss?
Because L-carnitine helps move more fatty acids into your cells to be burned for energy, itโs sometimes used as a weight loss supplement.
One review of 37 studies found that L-carnitine supplementation significantly reduced body weight, body mass index (BMI), and fat mass. However, it had no effect on belly fat or body fat percentage.
Another analysis of nine studies โ mostly in individuals with obesity or older adults โ found that people lost an average of 2.9 pounds (lbs), or 1.3 kilograms (kg), more weight while taking L-carnitine.
Whatโs more, a meta-analysis of six studies showed that L-carnitine could reduce body weight, BMI, and belly fat in people with polycystic ovary syndrome (16Trusted Source).
Still, more research is needed to understand how it may impact long-term weight loss.
Furthermore, while it may aid in weight loss for some people, you may wish to consult with a dietician to develop a thorough diet and exercise regimen first.
SUMMARY
Some studies suggest that L-carnitine could help promote weight loss and fat loss. However, more studies are needed.
Effects on brain function
L-carnitine may benefit brain function.
Some research suggests that the acetyl form, acetyl-L-carnitine (ALCAR), may help prevent age-related mental decline and improve markers of learning (13Trusted Source).
In fact, according to one 2018 study, taking 1,500 milligrams (mg) of ALCAR daily for 28 weeks significantly improved brain function in people with dementia.
However, other studies have turned up mixed results.
For instance, a 2017 review of two studies showed that taking L-carnitine for 3 days had no effect on markers of brain function โ including reaction time, vigilance, immediate memory, and delayed recall โ in young adults without cognitive impairment.
Therefore, more research is needed on the potential benefits of supplementation.
SUMMARY
L-carnitine โ specifically acetyl-L-carnitine โ may have beneficial effects on brain function. Still, more research is needed.
Other health benefits
A few more health benefits have been linked to L-carnitine supplements.
Heart health
Some studies demonstrate that L-carnitine could benefit several aspects of heart health.
For example, one review of 10 studies found that L-carnitine significantly reduced diastolic blood pressure, especially in people with overweight and obesity.
Another analysis of 17 studies showed that L-carnitine could improve heart function and decrease symptoms in people with congestive heart failure.
Additionally, a 2020 review showed that L-carnitine could reduce total and LDL (bad) cholesterol while increasing HDL (good) cholesterol in people at risk for heart disease.
Exercise performance
The evidence is mixed when it comes to the effects of L-carnitine on sports performance, but it may offer some benefits.
Keep in mind that L-carnitineโs benefits may be indirect and take weeks or months to appear. This differs from supplements like caffeine or creatine, which can directly enhance sports performance.
L-carnitine may benefit:
- Recovery: It may improve exercise recovery.
- Muscle oxygen supply: It can increase the oxygen supply to your muscles.
- Stamina: It might increase blood flow and nitric oxide production, helping delay discomfort and reduce fatigue.
- Muscle soreness: It could reduce muscle soreness after exercise.
- Red blood cell production: It may increase the production of red blood cells, which transport oxygen throughout your body and muscles.
- Performance: It could improve high intensity exercise performance when taken 60โ90 minutes before working out.
Type 2 diabetes
L-carnitine may be beneficial for people with type 2 diabetes.
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 (Trusted Source).
Depression
Some research suggests that L-carnitine could be beneficial for the treatment of depression.
In one review of 12 studies, acetyl-L-carnitine significantly reduced symptoms of depression compared with placebo (Trusted Source).
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.
Still, more research is needed to understand how L-carnitine may affect depression.
SUMMARY
Research suggests that L-carnitine may aid exercise performance and treat health conditions like heart disease, depression, and type 2 diabetes.
