As the name implies, acetyl-L-carnitine is an acetyl ester of L-carnitine, which is a natural molecule produced in the human body. Dietary sources of L-carnitine include animal products such as fish, meat, milk, and poultry. Both L-carnitine and acetyl-L-carnitine are also available as dietary supplements. (6) Keep reading to learn more about the health benefits of acetyl-L-carnitine and how it can improve mood, enhance energy levels, and promote weight loss.
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Health Benefits of Acetyl-L-Carnitine
According to scientific literature, there are many health benefits associated with acetyl-L-carnitine supplementation including:
- Enhances metabolism
- Positively influences mitochondrial function
- Provides pain-relieving effects in neuropathies
- Provides antioxidant and anti-apoptotic (cell death-preventing) activity
- Reduces neuroinflammation and neurodegeneration
L-carnitine exhibits many of these properties as well but the two are very different when it comes to absorption.
Acetyl-L-Carnitine vs L-Carnitine
Depending on the metabolic needs of the cell, enzymes convert L-carnitine to acetyl-L-carnitine and vice versa. The biggest differences between acetyl-l-carnitine and l-carnitine is that acetyl-L-carnitine more readily crosses the blood-brain barrier and is more easily absorbed in the gut compared to L-carnitine. (4)
Acetyl-L-Carnitine Supplementation Benefits
Because acetyl-L-carnitine has multiple mechanisms of influence on a cellular level, its health benefits are diverse. Taking acetyl-L-carnitine supplements can be a great way to take advantage of these benefits.
1. Supports Brain Function and Mental Health
Several double-blind controlled clinical trials have shown that acetyl-L-carnitine may have beneficial effects on Alzheimer’s disease and depression. (9) Because low levels of acetyl-L-carnitine and L-carnitine are linked to depression, a 2021 paper concluded that serum carnitine levels could be an effective biomarker for major depressive disorder. (7) A 2020 review of 37 different research papers explained that acetyl-L-carnitine can help slow cognitive decline through several mechanisms via the gut-liver-brain axis including promoting mitochondrial energy metabolism, protecting against toxin buildup in the brain, and exerting neurotrophic effects. (8)
2. Alleviates Diabetic Neuropathy
In 2005, an analysis of two different randomized placebo-controlled trials demonstrated that acetyl-L-carnitine was successful at alleviating symptoms of diabetic neuropathy, especially pain, compared to a placebo. In those two trials, acetyl-L-carnitine also improved nerve fiber regeneration. (11)
3. Influences Physical and Mental Fatigue
Because acetyl-L-carnitine impacts mitochondrial energy, it’s not surprising that it can positively influence both physical and mental fatigue. In fact, research demonstrates that patients with chronic fatigue syndrome have much lower levels of acetyl-L-carnitine and that when the diet is supplemented with acetyl-L-carnitine, there is a statistically significant improvement in energy levels, which could also improve exercise performance. This is due to the fatty acid oxidation that occurs as the fatty acids are transferred into and out of the mitochondria and turned into energy. (1)
4. Supports Weight Loss
L-carnitine is instrumental in energy and glucose metabolism, and its role in the fatty acid oxidation process burns fats and carbohydrates, which is why it can be a useful weight loss tool. (4)
A 2016 review and meta-analysis of randomized controlled trials found that L-carnitine supplementation helped participants lose significantly more weight, and they had decreased body mass index compared to the placebo group. (10)
5. Impacts Skeletal Muscle Health
L-carnitine plays a large role in skeletal muscle energy metabolism and optimal functioning. Skeletal muscle loss can lead to fatigue, strength loss, myalgia (muscle pain), and muscle cramps. Studies examining the effects of L-carnitine supplementation on exercise performance in particular show that it positively affects many of the factors involved in contributing to skeletal muscle loss and could be helpful against skeletal muscle diseases, though more research is needed. (5)
Acetyl-L-Carnitine and Alpha-Lipoic Acid
In some cases, acetyl-L-carnitine is combined with alpha-lipoic acid to enhance efficacy. For example, a 2021 acetyl-L-carnitine study showed that the combination of acetyl-L-carnitine and alpha-lipoic acid led to an increase in antioxidant capacity and a decrease in oxidative stress. (2)
Another study showed that the combination of acetyl-L-carnitine and alpha-lipoic acid was effective at improving blood pressure and vascular function in patients with coronary artery disease compared to placebo. (3) A 2008 review concluded that the combination of acetyl-L-carnitine and alpha-lipoic acid not only had neuroprotective properties, it also enhanced cognition. (12)
Carnitine Deficiencies
Carnitine deficiency can occur either genetically or as a result of certain disorders that reduce absorption or endogenous synthesis of carnitine, and/or increase its excretion. Carnitine deficiency alters muscle fuel metabolism causing muscle weakness, and can lead to seizures and increased risk of heart failure and cardiovascular disease. It can also cause an excess of myoglobin and dicarboxylic acids in the urine. L-carnitine supplementation is a great way to combat carnitine deficiency. (6)
Acetyl-L-Carnitine Provides a Variety of Health Benefits
Acetyl-L-carnitine supplementation may provide a variety of health benefits from improved mood to enhanced energy to weight loss. It’s often the preferred form of L-carnitine because of its higher absorption and ability to cross the blood-brain barrier.
If you are interested in trying acetyl-L-carnitine as a dietary supplement, please discuss it with your integrative healthcare practitioner first. If you’re a practitioner, log-in to your Fullscript account to start recommending supplements.
