L-carnitine supplements have grown in popularity in recent years.
Today, many people take L-carnitine supplements regularly for everything from energy to brain function. The amino acid works by transporting long-chain fatty acids into the powerhouses of your body, boosting energy at the cellular level.
Is L-carnitine legit? Do L-carnitine supplements really work? Keep reading to discover the most science-backed benefits of L-carnitine.
How L-Carnitine Works
L-carnitine is an amino acid linked to energy, heart function, and brain function, among other benefits.
Your body produces L-carnitine in the brain, liver, and kidneys.
The most important function of L-carnitine is to transport fatty acids into the mitochondria of your cells, which is why L-carnitine is so important for energy production.
Although your body produces L-carnitine on its own, it needs vitamin C to produce sufficient L-carnitine. You can also get L-carnitine from certain animal products, including meat and fish.
You May Be Deficient in L-Carnitine
If you have low physical or mental energy, mental fog, or other noticeable issues, then you may be deficient in L-carnitine.
Having low energy isn’t normal at any age! A single test can check for L-carnitine deficiency.
Many vegans and vegetarians are deficient in L-carnitine, for example. Because the most common sources of L-carnitine are meat and fish.
Some people also have a genetic condition that makes it impossible to produce sufficient L-carnitine.
For all of these reasons and more, you may want to:
- Take a painless Science Nutrition Lab test to spot changes in your blood before you notice symptoms
- Take an L-carnitine supplement
- Talk to a doctor about a customized treatment plan
Benefit #1: Weight Loss
L-carnitine could support weight loss and healthy weight management, according to multiple studies.
One of the largest reviews on L-carnitine found the amino acid led to average weight loss of 2.9lbs (1.3kgs) more than a placebo. That study reviewed 9 trials involving hundreds of participants taking L-carnitine in double-blind, placebo-controlled settings.
Now all L-carnitine studies have been conclusive for weight loss, however. One study found people taking L-carnitine over a four week period while riding a stationary bike for 90 minutes a day did not lose more weight than those taking a placebo, for example. In a separate 8-week study, 38 women experienced no difference in weight loss whether taking L-carnitine or a placebo.
Overall, L-carnitine could help with weight loss in some people. Although it’s not proven to work in everyone, it could support weight loss in some.
Benefit #2: Cognition & Mental Fog
If you experience mental lethargy, brain fog, or occasional cognitive issues, then L-carnitine could help. L-carnitine plays a crucial role in neurotransmitter production, helping to support messengers within your brain.
Many of the cognitive effects of L-carnitine are linked to a specific version of the amino acid called acetyl L-carnitine. Also known as ALCAR, this version may help prevent age-related mental decline. A separate study also found ALCAR enhanced learning capacity in aging rats.
Researchers gave ALCAR to a group of patients with Alzheimer’s disease to assess the effects. Participants took 2.5g of ALCAR per day or a placebo for 6 months. Researchers found this dose of ALCAR was associated with an improvement in certain cognitive symptoms of Alzheimer’s.
There’s even some evidence L-carnitine could help support mental acuity in people with addiction. In a 90 day trial, people with alcohol addiction taking 2g of L-carnitine per day improved all measures of brain function.
Overall, L-carnitine plays a critical role in mental and physical energy, and multiple studies have validated the effects of L-carnitine on brain health.
Benefit #3: Cardiovascular Health
There’s some evidence L-carnitine can help with blood pressure and overall cardiovascular health. One study found L-carnitine reduced blood pressure, for example, while another study found L-carnitine reduced cardiovascular inflammation, which is associated with heart disease.
Heart disease is the number one killer in most developed countries. Statistically, most are more likely to die of heart disease than any other cause.
In one 2009 study, researchers found daily intake of 2g of L-carnitine led to a 10-point drop in systolic blood pressure (the top number of a blood pressure reading). This number is considered particularly important for managing the risk of heart disease, heart attack, and stroke.
A separate study found L-carnitine supplementation was linked to a significantly reduced risk of heart failure over a 12 month period.
Benefit #4: Blood Sugar
There’s some evidence L-carnitine can help with blood sugar, and some diabetics take L-carnitine supplements regularly for that reason.
Some of the blood sugar-linked benefits of L-carnitine include:
A 2010 study found a combination of L-carnitine supplementation and caloric restriction improved insulin sensitivity in patients with impaired glucose metabolism. Participants followed a restricted diet while taking a placebo or 4g of L-carnitine daily. Researchers found the L-carnitine group had better insulin sensitivity than the group following a restricted calorie diet alone.
A 2011 study found L-carnitine improved insulin sensitivity in a group of overweight and obese males. Participants took 3g of L-carnitine or a placebo daily. At the conclusion of the period, researchers found significant differences in body mass, fat percentage, and BMI between the L-carnitine group and placebo group, suggesting L-carnitine can provide “insulin-like” actions on tissues, according to researchers. However, the study was small and involved 16 male participants in total.
A separate study also found a connection between carnitine, fatty acids, and insulin resistance, and researchers found 2g of L-carnitine supplementation per day helped with the regulation of blood sugar.
Overall, there appears to be a connection between L-carnitine and blood sugar management, and many diabetics take L-carnitine supplements regularly for that reason.
Benefit #5: Athletic Performance, Endurance, and Recovery
Many people take L-carnitine supplements before a workout. In fact, L-carnitine is one of the most popular preworkout supplement ingredients on the market.
L-carnitine appears to work by supporting blood flow and nitric oxide production, which can help with stamina, endurance, and the longevity of your workout. Some bodybuilders take L-carnitine for a better “pump” and vasodilation, for example, while endurance athletes could take L-carnitine to workout harder for longer.
L-carnitine also appears to work by increasing the production of red blood cells. Your body needs red blood cells to transport oxygen to your muscles. When you’re working out, your red blood cells play a critical role in performance, endurance, and overall athletic activity.
Others take L-carnitine after a workout. Multiple studies have found L-carnitine could improve exercise recovery, helping your body repair muscles and tissues after a workout.
Final Word
We’ve known about the effects of L-carnitine for a while. However, growing research continues to connect L-carnitine to heart health, brain health, blood sugar management, energy, and more.
Do you have brain fog or low energy? Do you regularly feel tired? That’s not normal at any age!
Consider taking a Science Nutrition Lab test to check for L-carnitine deficiency and other deficiencies to address your low energy.