The supplement market is brimming with ingredients touted to support the incineration of body fat, but unfortunately, this promise doesn’t always pan out. Several factors play into a successful fat-loss plan and supplements should always be viewed as the icing on the cake. After all, supplements, ahem, supplement our diet and training efforts. They aren’t shortcuts or cheat codes!
Now that we’ve got that supplement PSA out of the way, I do want to talk about one fat-loss supplement that’s come under the microscope in recent years: l-carnitine (often referred to as just “carnitine”). We have done multiple studies on l-carnitine at my lab in Tampa, so I’ve got a lot of first-hand research and training experience with this popular supplement. Here’s what you need to know about l-carnitine—and how it can support your efforts to get shredded.
What is L-Carnitine?
When we talk about fat loss, we often hear the phrase “burning fat,” as if our body is some sort of fat-burning engine. And, well, it kind of is! We don’t actually “burn” fuel like other engines (that would be painful), but the sentiment remains the same.
We burn fat during every second of every day. Our fat stores are a great source of energy for us, and could provide steady energy for weeks should we end up on a deserted island. In order to burn fat, though, we need to be able to transport fatty acids to our mitochondria, the “powerhouses” of our cells, which use them to produce energy.
So, how do fatty acids get to the mitochondria? Do they just waltz on in? Not quite. They need transport molecules—essentially little taxis that transport the fat into the mitochondria. Enter, l-carnitine!
L-carnitine is a conditionally essential nutrient. This means we both ingest it through our diet or produce it by combing the amino acids lysine and methionine. We typically get this nutrient through foods like meat and seafood, so supplementation might be necessary if you don’t eat them.
Can L-Carnitine Help You Burn Fat?
Since it’s stored in the heart and muscles, researchers and athletes alike have pondered l-carnitine’s usefulness in performance and weight loss.
Fat-Loss Basics To Keep In Mind
Before we get into the nitty-gritty of l-carnitine and fat loss, though, let’s review the fat-loss basics. To lose significant fat, you typically need to focus on the following foundation:
- You should probably be burning more calories than you consume. You can certainly lose fat without this step, but it’ll be a much slower process and you’ll also need to do some sort of muscle-building exercises.
- You should eat a little more protein to ensure most of your weight loss is fat and not muscle. (This will probably increase your intake, but l-carnitine itself isn’t solely responsible for this effect.)
- You should also plan on keeping a consistent sleep schedule, as studies show that poor sleep can impair fat-loss efforts.
With all of that in mind, there are a couple of l-carnitine caveats to know about, too:
- L-carnitine is likely most beneficial for those who don’t get enough in their diet, particularly vegetarians, vegans, or anyone who doesn’t eat meat or much seafood.
- Some studies also show greater fat loss in older subjects. That said, the authors of one paper speculate that older adults supplementing with the nutrient had more energy and lost weight as a result of being more active.
So, can l-carnitine help you burn fat if you don’t fall into either of these groups? While it sounds appealing, we don’t have a ton of research showing significant fat or weight loss in the average person.
However, though findings have been somewhat inconsistent, some studies link l-carnitine supplementation and increased fatty acid oxidation (a.k.a. burning fat for energy) during exercise. Plus, some of the enzymatic pathways L-carnitine supplements activate could boost overall energy expenditure. Some studies also show that it can improve exercise performance, which could absolutely mean you burn more calories and shed more fat.
L-carnitine may also offer post-workout benefits. Animal research has shown it to be important for recovery from exercise. And my lab recently finished a study showing similar results in humans. (We’ll be publishing that one soon!) We need energy to recover from training—and what provides this energy? Usually fat. So, by promoting our body’s ability to use fat for energy, the nutrient helps us recover from training, which is a must if we want to see results.
How to take L-Carnitine
Though l-carnitine isn’t a fat-loss magic bullet, it can certainly be a worthy component of your plan to get shredded.
If you’re interested in l-carnitine supplements, look for “Carnipure®” on the label. Typically, studies using Carnipure® branded l-carnitine, which is created by a reputable lab, show the most promising results.
When it comes to l-carnitine timing, you probably don’t need to be super-picky. In the l-carnitine studies that we’ve conducted, we typically have subjects take two to three grams 30 minutes before exercise (or with their first meal of the day on non-exercising days). As long as you get about that amount per day, I think you’re set.
Like I mentioned earlier, it’s important not to rely on supplements as short cuts to fat loss. Like it or not, you’re going to have to work hard to maximize fat loss. That said, while we don’t have a ton of data on l-carnitine for fat loss in weight-healthy subjects, I still think it can be useful.
- L-carnitine might improve exercise performance and work capacity. This can increase how many calories you burn during exercise, which would absolutely aid in fat loss.
- The nutrient can also enhance exercise recovery, which should allow you to train at a greater intensity more often. There’s nothing more important than consistent effort when it comes to losing fat, and l-carnitine can absolutely help on that front.
- It has also been shown to boost fat oxidation during exercise.
Combine these benefits with a healthy diet, solid protein intake, and plenty of sleep, and you should have a recipe for success.
I also think l-carnitine can be especially helpful for vegan or vegetarian athletes and older individuals. Younger, omnivorous individuals will probably still reap some benefits; however, they may not be quite as noticeable.
References & Further Reading
- Annals of Internal Medicine: Insufficient sleep undermines dietary efforts to reduce adiposity
- The American Journal of Clinical Nutrition: L-Carnitine treatment reduces severity of physical and mental fatigue and increases cognitive functions in centenarians: a randomized and controlled clinical trial.
- Nutrients: A Dose-Dependent Effect of Carnipure® Tartrate Supplementation on Endurance Capacity, Recovery, and Body Composition in an Exercise Rat Model.
- Metabolism: The effect of l-carnitine on fat oxidation, protein turnover, and body composition in slightly overweight subjects.
- Current Opinion in Investigational Drugs: Modulation of carnitine palmitoyltransferase-1 for the treatment of obesity.
- The Journal of Physiology: Chronic oral ingestion of l‐carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise in humans.
Known as ‘The Muscle Ph.D.,’ Dr. Jacob Wilson has a knack for transforming challenging, complex concepts into understandable lessons that can support your body composition and health goals. A skeletal muscle physiologist and sports nutrition expert, Wilson is a leader in muscle sports nutrition. As the CEO of The Applied Science & Performance Institute and researches supplementation, nutrition, and their impact on muscle size, strength, and power.