Peripheral neuropathy, a common neurological condition, may develop due to a variety of reasons, such as diabetes, HIV, certain medications, and chemotherapy treatment. The typical symptoms include numbness and tingling, weakness, and burning or stabbing pain. There are a variety of methods utilized to either prevent or mitigate peripheral neuropathy, and one potential option with increasing amounts of research into its efficacy and safety is acetyl-L-carnitine.

Acetyl-L-carnitine is an acetyl ester of L-carnitine, which is synthesized in the body from the amino acid carnitine. It contributes to energy production by supporting the metabolism of fatty acids and the synthesis of acetyl-coenzyme A, the central substrate for energy production that also helps maintain homeostasis between catabolic and anabolic reactions. Acetyl-L-carnitine also plays a role in detoxification and has antioxidant properties. 

It also may support the nervous system in many ways beyond its role in energy production, including affecting neurotransmitter production and secretion. It provides acetyl groups for the synthesists of acetylcholine, leading to a cholinergic effect, and it may modulate synaptic transmission. Acetyl-L-carnitine may also affect dopamine and gamma-aminobutyric acid (GABA) levels and activity, and it reduces glutamate concentration in the synapsis, which provides an analgesic effect. 

Another way that acetyl-L-carnitine may support normal nervous system function is by imparting neuroprotective and neurotrophic effects, which includes influencing the action of nerve growth factor and promoting peripheral nerve regeneration and repair. This may increase the number of myelinated axons and the thickness of the myelin sheath, and also increase nerve conduction velocity. Together, these mechanisms may support a healthy nervous system and a normal pain response, which has led to research into whether it may be beneficial in neuropathy.

Several randomized controlled trials have assessed the efficacy of acetyl-L-carnitine. A systematic review and meta-analysis of many of these studies testing supplementation on painful peripheral neuropathy found that supplementing with acetyl-L-carnitine improved symptoms, including pain, due to neuropathy from different sources, including diabetes and chemotherapy. The meta-analysis found a reduction in pain equivalent to 20.2% compared to baseline in those taking the supplements. There were also benefits to nerve conduction parameters and nerve fiber regeneration. Another systematic review and meta-analysis likewise found acetyl-L-carnitine effective in reducing peripheral neuropathic pain, especially due to diabetes.

The etiology and presentation of neuropathy may influence the treatment protocol that a physician or health-care practitioner may wish to recommend to a patient. Studies are pointing to the potential for acetyl-L-carnitine to support a healthy nervous system and normal pain response.

By Kendra Whitmire, MS, CNS