What is acetyl-L-carnitine?
L-carnitine is a non-essential amino acid that your body can produce itself - at least in certain quantities - from the amino acids lysine and methionine. However, this production is not sufficient to cover an increased need for carnitine, as can occur, for example, in intensively training athletes.
L-carnitine is involved in a number of important processes in the body, the best known of which is the transport of fatty acids from the fat cells to the mitochondria, where these fatty acids are burned to provide energy. However, L-carnithine has a number of other benefits that are of great interest not only for athletic performance, regeneration and muscle building, but also for many aspects of health.
Why is acetyl-L-carnitine so much better than regular L-carnitine?
As the name suggests, acetyl-L-carnitine is a form of carnitine - more precisely, an esterified L-carnitine molecule. Due to this esterification, acetyl-L-carnitine has a much better fat solubility and can therefore be absorbed faster and better in the intestine than regular L-carnitine.
In addition, acetyl-L-carnitine can be transported better and more easily via the intestine from the liver into the bloodstream and other parts of the body, which becomes particularly important with increasing age, when this onward transport is poorer and less effective with regular L-carnitine.
What are the benefits of acetyl-L-carnitine for athletes?
Increase in athletic performance:
Acetyl-L-carnitine can boost athletic performance via several mechanisms that can significantly increase your muscles' stamina and delay the onset of fatigue, allowing you to perform more repetitions per set and more endurance training before you run out of juice.
One of the reasons for this is that carnitine can reduce both ammonia production in response to intense training (1) and lactate production (2). Both increased lactate levels and increased ammonia levels promote the onset of muscle fatigue, which is why a reduction in these levels can significantly increase training performance during resistance training (2) and endurance training.
In addition, L-carnitine supplementation increases muscle carnitine levels, resulting in up to 50% more fat burning and significantly increased energy production, which leads to a significant reduction in fatigue (3) and conserves muscle glycogen reserves. This effect appears to be particularly pronounced after depletion of muscle glycogen reserves (4), so that intensive training is still possible even when glycogen stores are depleted.
In addition, L-carnitine can increase the blood supply and therefore also the supply of oxygen, urgently needed nutrients and the body's own anabolic hormones by improving blood flow to your muscles (5), which will of course also have a positive effect on your muscle performance. This increased blood flow is due to increased nitric oxide production (6), which is caused by an increase in plasma nitrate levels (7).
Improvement and acceleration of regeneration:
Acetyl-L-carnitine can speed up your post-workout recovery via a whole range of mechanisms. This starts with a significant reduction in exercise-induced muscle damage (8, 11), allowing for faster recovery as there is simply less to repair.
In addition, there is a pronounced antioxidant effect that neutralizes free radicals (8, 9), which are produced to a greater extent as waste products of energy metabolism during intensive training sessions. These free radicals can damage muscle cells and genetic material and significantly extend the duration of regeneration. This antioxidant effect is achieved by a significant increase in the levels of the body's 3 strongest antioxidant enzymes glutathione peroxidase, superoxide dismutase and catalase (10) - even after the first intake! In addition, acetyl-L-carnitine can significantly reduce muscle soreness after training (11).
Promotion of muscle building:
Of course, increased performance and faster recovery can allow you to do more frequent, more intense workouts, which will result in increased stimulus for muscle building. In addition to this, L-carnitine can also increase the androgen receptor density in your muscles (12), so that your body's own anabolic hormones can have a stronger muscle-building effect. Such a muscle-building effect has even been observed in older people who only did light training (13).
Supporting fat loss:
Without L-carnitine, your body cannot transport fatty acids from the fat cells to the mitochondria where they are burned, which in other words means that your fat loss will be severely limited if your body lacks L-carnitine. In addition, L-carnitine activates the enzymes of the respiratory chain, which are responsible for generating energy from fatty acids.
Scientific studies show that L-carnitine supports both the release of fatty acids from fat cells and their combustion (14) and that supplementation with L-carnitine results in increased combustion of long-chain fatty acids (15).
What are the health benefits of acetyl-L-carnitine?
Acetyl-L-carnitine has a variety of health benefits, including positive effects on cardiovascular health. Not only can L-carnitine improve blood flow, as previously mentioned, but it can also lower elevated blood pressure (16) and even reduce the symptoms of arterial occlusive disease caused by atherosclerosis (17).
The effects of carnithine on blood sugar levels and the risk of diabetes appear to be very pronounced. Carnitine can increase insulin sensitivity, increase the effectiveness of pancreatic beta cells responsible for insulin production and lower blood glucose levels (18), as well as reduce insulin levels in a fasting state - which is the case even in people with reduced insulin sensitivity (19). Furthermore, carnitine can increase chronically low adiponectin levels in overweight people (20), which is important because low adiponectin levels can attenuate insulin action and increase the risk of diabetes.
In addition to this, carnitine can improve concentration and reduce mental fatigue (21), as well as lowering levels of critical liver enzymes and improving liver function (22). And as if all this wasn't enough, studies suggest that carnitine can improve sperm quality in reduced fertility (23) and alleviate existing erectile dysfunction (24).
