L-Carnitine is an important compound made by most mammals and plays an important role in energy metabolism. L-Carnitine is synthesized in the liver, kidneys, and brain and helps you convert fat into energy by transporting long-chain fatty acids to the mitochondria for energy generation. This means that L-carnitine helps convert fat into energy, which may be beneficial for your weight loss goals.
Composed of the amino acids methionine and lysine, L-carnitine can be considered a conditionally essential nutrient for vegetarians.
There are many types of L-Carnitine, however, Acetyl-L-Carnitine, which is known to be extremely effective for brain health, and L-Carnitine, which is known for enhancing exercise benefits, are the most common and powerful forms found in supplements.
The function of L-carnitine
L-Carnitine has many functions and supports several physiological processes that contribute to your overall health and well-being.
L-Carnitine's primary role is to support your mitochondria. Mitochondria are the energy powerhouses within cells. Their job is to generate energy for cells and for your body to function properly.
L-Carnitine stores fatty acids in mitochondria for energy. It also helps to remove waste or metabolites from cells. This is important to prevent waste buildup and intracellular toxicity.
By optimizing mitochondrial function, L-Carnitine enhances energy production and fatty acid utilization in the body. Optimizing mitochondrial function is also critical for healthy aging and disease prevention.
Some research suggests that L-carnitine may be good for the brain. Some studies have found that taking a daily dose of acetyl-L-carnitine helps reverse the decline in brain function in people with Alzheimer's and other neurodegenerative diseases that affect the brain.
Acetyl-L-carnitine also benefits brain function in older adults without any type of brain disease.
Animal studies have also shown good results with acetyl-L-carnitine supplementation. In animal studies, it helped prevent mental decline associated with aging. Learning ability was also improved in aged rats supplemented with acetyl-L-carnitine.
In a study evaluating patients with alcohol addiction, all measures of brain function were substantially optimized. The study gave patients 2 grams of acetyl-L-carnitine for 90 days.
Cardiac diseases such as chronic heart failure, high blood pressure and coronary arteriosclerosis are optimized with L-carnitine supplementation.
One study found that taking two grams of acetyl-L-carnitine per day significantly lowered systolic blood pressure by 10 points.
Another study found an improvement in patients with severe heart disease, including hardening of the coronary arteries and chronic heart failure. Patients supplemented with L-carnitine had fewer deaths.
Oral L-carnitine has been found to improve exercise capacity and optimize symptoms in people diagnosed with heart failure.
High cholesterol, or hyperlipidemia, improves after taking L-carnitine oral supplements.
Angina, or chest pain, was optimized after L-carnitine supplementation, and exercise capacity was enhanced, as was chest pain in patients with cardiac syndrome X. Cardiac syndrome X is a condition in which people have chest pain but no blocked arteries.
Type 2 diabetes
Supplementation with L-carnitine has been shown to significantly reduce blood sugar levels in diabetic patients taking anti-diabetic formulas.
L-carnitine may also optimize diabetes by increasing AMP kinase, an enzyme that enhances the ability to utilize carbohydrates.
One study found that whole-body glucose uptake was significantly higher with L-carnitine than with the control group. The study believes that L-carnitine can improve insulin sensitivity in patients with insulin-resistant diabetes.
Sports Performance and Recovery
Due to L-Carnitine's key role in energy metabolism, it has been studied to determine its potential for enhancing athletic performance and recovery.
Preliminary studies have shown that L-carnitine supplementation has positive effects on acute performance, including increased power output and outsized oxygen consumption at the cellular level.
Other studies have shown that L-carnitine supports post-exercise repair by attenuating muscle damage and reducing markers of cellular damage. Studies have also found that L-carnitine supplements reduce free radical formation while reducing muscle soreness after exercise.
L-Carnitine is believed to enhance blood flow and oxygen supply to muscle tissue, thereby optimizing cellular function.
Studies in older adults have shown that L-carnitine supplements can increase muscle mass while reducing body weight, with the added benefit of reducing physical and mental fatigue.
In animal studies, L-carnitine has been shown to play a role in preventing age-related muscle protein degradation.
L-Carnitine improves male fertility by increasing sperm count and motility in men with fertility problems. This in turn can increase the chances of pregnancy.
Female fertility may also be affected by L-carnitine. Research shows that for women diagnosed with polycystic ovary syndrome (PCOS), taking L-carnitine by mouth can increase the chances of ovulation and pregnancy. Polycystic ovary syndrome is a condition in which the ovaries are enlarged with cysts.
One study found that other PCOS symptoms, such as hirsutism (male-pattern hair growth in women) and irregular menstrual cycles, improved with L-carnitine supplementation. The study also showed significant improvements in the women's BMI (body mass index) and insulin sensitivity. In addition, the participants' bad cholesterol, low-density lipoprotein (LDL), had decreased, while their good cholesterol, high-density lipoprotein (HDL), had increased. These findings were observed after participants took three grams of L-carnitine daily for three months.
Some studies point to the benefits of L-carnitine supplementation for weight loss.
One study found that obese adults and older adults lost an average of 2.9 pounds more than those who did not take L-carnitine.
Most studies have used adults with oral doses of 2-3 grams of L-carnitine per day. In children, 50-100 mg/kg orally per day is very often used.
L-Carnitine Side Effects
L-carnitine is considered Possibly Safe when taken by mouth. However, some side effects may occur.
Possible gastrointestinal side effects of L-carnitine supplements include upset stomach, diarrhea, nausea, and heartburn.
Fishy breath, sweat, and urine may also occur with L-carnitine supplements.
In people with or without epilepsy, epilepsy attacks have been associated with taking L-carnitine. Specifically, acetyl-L-carnitine may increase serotonin levels in the brain. Concomitant use of other medications that also increase serotonin, such as antidepressant medications such as selective serotonin reuptake inhibitors (SSRIs), may cause serotonin syndrome. This serious condition can cause muscle twitching or stiffness, confusion, epileptic seizures, profuse sweating, diarrhea, and irregular heartbeats.
L-carnitine has been found to increase the likelihood of epileptic seizures in those patients who have had epileptic seizures in the past. Do not take L-carnitine if you have had a seizure in the past.
L-carnitine might make symptoms of hypothyroidism worse.
Prescriptions that interact with L-carnitine include thyroxine, warfarin, and acenocoumarol. L-carnitine may decrease the superiority of thyroid hormones while increasing the superiority of warfarin and acenocoumarol, two blood-thinning prescriptions.
Over time, L-carnitine might raise blood levels of trimethylamine oxide (TMAO). High levels of TMAO have been linked to an increased risk of atherosclerosis, a disease that clogs arteries.
Always consult a physician before taking L-carnitine or any other dietary supplement, especially if pregnant, breastfeeding, or taking other prescriptions.