L-carnitine seems to be making a comeback as of late. If you are familiar with this nutrient, it was previously made popular for its role in fat burning. More specifically for its role in the carnitine shuttle system where L-carnitine helps to deliver fatty acids into the mitochondria for beta-oxidation. Without sufficient carnitine, fatty acids cannot efficiently enter the mitochondria (even if there are abundant fat stores).

But now, the landscape has changed a bit. Now, it’s ALL about the mitochondria.

As a refresher, mitochondria are the engines of life and athletic performance. They determine how efficiently our bodies produce energy, spare glycogen, recover between exercise, and adapt to training and you have probably figured out that L-carnitine does indeed play a role in mitochondrial health and metabolic efficiency.

In case you have never heard of L-carnitine, it is a conditionally essential nutrient synthesized from the amino acids lysine and methionine, primarily in the liver and kidneys. That means our bodies can make it. 

It's also obtained from food, especially in red meat and dairy, which is interesting given the new Food Guide Pyramid. But that’s a topic for a future article.

Over 95% of carnitine is stored in skeletal muscle, highlighting its importance in exercise metabolism.

Why is this so important? That’s easy to answer once you know the benefits of L-carnitine, especially for active individuals and athletes.

#1 - It can improve mitochondrial energy production.

As mentioned previously, by facilitating fatty acid entry into mitochondria, L-carnitine can enhance fat burning, ATP (energy) production and energy efficiency during prolonged exercise or repeated, higher intensity efforts.

#2 - It can enhance metabolic efficiency.

Similar to #1, it can improve fat burning at lower to moderate exercise intensities and improve carbohydrate burning at higher exercise intensities. Double bonus!

#3 - It can reduce the accumulation of metabolic byproducts.

L-carnitine buffers excess acetyl-CoA inside the mitochondria by forming acetylcarnitine, which can reduce metabolic stress, support carbohydrate oxidation and improve efficiency during higher exercise intensities.

#4 - It can improved recovery and reduce muscle damage.

Research shows L-carnitine supplementation may reduce exercise-induced muscle damage, lower markers of oxidative stress, and improve blood flow via nitric oxide signaling.

#5 - It can support the environment needed for mitochondrial adaptations.

Emerging evidence suggests L-carnitine may support signaling pathways involved in mitochondrial enzyme activity, fat oxidation gene expression, and long-term metabolic adaptations to training

Sounds pretty good, doesn’t it?

I’ve had many athletes ask me if they should supplement with L-carnitine and my answer is always, “it depends”. It really does because you have to analyze your current training status, health and longevity goals and daily nutrition plan. 

Overall, if you are a vegetarian or vegan, restrict red meat or dairy, train high mileage, have multiple training sessions per day, have longer competitive seasons and are more “mature” (okay, older), then L-carnitine supplementation may be advantageous. 

But of course, please consult your favorite Sports Dietitian first!

Remember, if you do choose to supplement with L-carnitine, it should be thought of as a foundational supplement, not a shortcut to improving health, longevity and athletic performance.

One last thing to note - there are different forms of L-carnitine, one that is better for performance and recovery and one that has additional cognitive benefits so be sure you understand your goals for supplementing.

And better yet…reach out to our awesome team of Sports Dietitians at eNRG Performance if you would like us to guide you in your daily nutrition and supplement strategies. We would love to help!