Carnitine is beneficial for muscle growth and a lean body, as it:
- burns belly fat for energy
- preserves muscle glycogen
- reduces muscle lactate accumulation
- promotes muscle recovery
However, most healthy athletes won’t benefit from taking high doses from supplements. The body synthesizes more than enough carnitine. Also, we can get high amounts from food.
Carnitine for muscle hypertrophy
Carnitine is a popular supplement among athletes and fitness enthusiasts, as it’s a compound that is found mainly in the muscles and acts as a fat burner. In fact, carnitine burns body fat for energy.
Therefore, athletes take carnitine to build muscle mass, improve performance, increase energy levels, and even decrease fat percentage. But, there aren’t consistent evidence that carnitine supplements can improve sport performance or body composition in healthy athletes.
First, carnitine supplements may help athletes spare their glycogen storage. Especially, during low-intensity exercise (50% VO2max). It seems that carnitine burns body fat for energy, instead of muscle glycogen. Furthermore, carnitine can reduce muscle lactate accumulation at high intensity exercise.
So, carnitine is beneficial for endurance athletes and athletes who do resistance training for muscle growth and strength. According to a small study, carnitine supplementation increased work output of exercise by 11%.
Moreover, increased carnitine intake can reduce metabolic stress, physical fatigue and promote recovery after exercise. So, it may enhance athletic performance.
Furthermore, L-carnitine supplementation could limit the imbalance between protein synthesis and protein breakdown, supporting muscle growth.
Do I need carnitine supplements to build muscle mass?
Certainly, carnitine plays a key role in energy metabolism, and it’s good for weight loss. But, research finds no consistent evidence that carnitine supplements can indeed improve physical performance or increase muscle growth.
For instance, some studies have reported that taking a carnitine dose of 2–4 grams a day from supplements can increase energy levels, and endurance capacity during physical exercise.
On the contrary, other studies didn’t show beneficial effects of L-carnitine supplementation for improving aerobic or anaerobic exercise performance. Moreover, carnitine supplements don’t increase the body’s use of oxygen or the amount of carnitine in muscle.[1,4]
After all, the human body can synthesize more than enough carnitine and the kidneys reabsorbs most of it. Healthy people don’t need to consume foods with carnitine, such as meet & dairy, or take carnitine supplements. Even vegans don’t need carnitine supplements. Plant-based foods are poor in carnitine!
Last, but not least, the human body synthesizes carnitine from the essential amino acids methionine and lysine! Athletes should consume foods rich in these two amino acids.
The richest foods in methionine are eggs (3.1g per 100g), cod (3g), chicken (2.8g), beef (2.6g), pork (2.6g), milk (2.5g), rice (2.4g), corn (2.1g), wheat and oats (1.8g), sesame seeds (1.6g), rye and beans (1.5g), cauliflower (1.4g), Brazil nuts (1.1g). hemp seeds (0.9g), soy protein (0.8g), chia seeds (0.6g), peanuts (0.3g), chickpeas (0.25g), and almonds (0.15g).
The richest foods in lysine are high-protein foods from animal sources, such as eggs, meat, and fish. Also, all beans and legumes are pretty high in lysine!