Acetyl L-carnitine (ALCAR) is a form of carnitine that is produced by the body in small amounts. It has been the focus of many human and animal trials because of its numerous novel effects particulalrly on HIV , male infertility  and diabetes mellitus .
The discovery of free carnitine in 1905 was credited to Russian scientists who isolated carnitine from bovine muscle. In 1955, another scientist discovered the role of L-carnitine in lipid metabolism acceleration – an event important for cellular energy production. Subsequent studies revelaed that L-carnitine can be obtained from fish, poultry and meat.
Another pioneering study also showed that L-carnitine is lowered to strict vegetarians. Albeit carnitine is not an essential diet component, the International Nutritional Conference in 1985 held in Chicago identified carnitine as an essential nutrient for body functioning. Use of carnitine as medication is focused mainly on carnitine nutritional deficiency .
Acetyl L-carnitine is an ester of L-carnitine and trimethylated amino acid. It is produced by the kidney, brain and liver through utilizing ALC transferase. ALC has comparable chemical structure to acetylcholine demonstrating similar cholimemetic attributes .
[msgbox]Chemical name/IUPAC: (R)-3-acetyloxy-4-trimethylammonio-butanoate
ALCAR is administered intravenously or orally. It is absorbed on the jejunum through simple diffusion. ALCAR administration increases ALCAR levels in the cerebrospinal fluid which indicates that it crosses the blood brain barrier. As such, it is readily absorbed and metabolized by the body resulting to immediate effects.
Mechanism of actions
The modes of action of ALCAR are still unclear. However, early and recent literature indicates that it may be related to its effects in mitochondrial metabolism. ALCAR plays a major role in cellular energy production and dissemination. It also regulates metabolic pathways as it is a cofactor of long chain fatty acid transport via the mitochondria. ALCAR synthesis, it is now able to cross the blood brain barrier reaching areas in the brain where the acetylic group is delivered.
Through modifying the acetylic groups, ALCAR is able to reactivate coenzyme A, preserve intramitochondrial salvage pathways, reduce peroxidation and enhance neurotransmitter synthesis . Additionally, it maintains cell membrane fluidity whilst provide a substrate to which it can promote production of cellular energy and subsequently prevent neuronal cell death.
Other mechanisms of action associated to ALCAR include its cholinergic effects wherein it is said that it has the ability to block post-synaptic inhibition. It has also been suggested that it directly stimulates the synapses. Some studies even claim that it promotes nerve growth factor and the binding of glucocorticoids in the hippocampus.
Alzheimer’s disease treatment
The abnormalities related to acetyl choline are the main culprit for Alzheimer’s disease (AD). In previous animal studies, it was discovered that ALCAR promotes the release and synthesis of acetylcholine. TO prove its efficacy, a group of researchers performed an open study to assess the efficacy of ALCAR in conjunction with rivastigmine or donepezil.
23 individuals diagnosed with mild AD who have not showed any positive reaction from acetylcholinesterase inhibitors were treated with ALCAR for 2 months. Evaluation of results revealed that combination therapy of donepezil/rivastigmine and ALCAR is beneficial to AD patients who were unresponsive to acetylcholinesterase inhibitors therapy .
Minimal Encephalopathy Treatment
Minimal hepatic encephalopathy (MHE) is one of the most prevalent complications amongst individuals with liver cirrhosis. It is characterized by increased ammonia levels which subsequently affect concentration, reaction time, personality, memory and psychomotor functions. A randomized, double-blind study was carried out to assess the efficacy of ALCAR in treating MHE. In this study, 125 patients with hepatitis B virus, hepatitis C virus and cryptogenic cirrhosis were enrolled as participants.
Participants were randomly divided into ALCAR therapy (group A) and placebo therapy (group B). The groups received their assigned drug therapy for 90 days. The effects of the drugs were assessed using the Mini Mental State Examination (MMSE) and Auditory Verbal Learning Test (AVL). Although there were no significant differences observed on either group’s EEG results, the ALCAR group demonstrated substantial enhancement of neuropsychological functions and greater decrease in serum ammonia levels .
Sciatic pain treatment
In some studies, it was discovered that ALCAR can produce analgesic, neuroprotective and peripheral nerve regeneration effects. Thus, a randomized double blind study was performed to assess its efficacy on treating sciatic pain on individuals with herniated disc. A total of 64 patients aged 29 to 85 with reports of moderate sciatica and acute backache were enrolled in the study.
Participants were divided into two groups. The first group received ALCAR and the second group received thioctic acid for 60 days. Efficacy of both drugs was assessed using electromyography and questionnaires. Results showed that both treatments led to substantial neuropathic improvement. Although thioctic acid seemed to promote greater impact, this study demonstrated that ALCAR can help in treating sciatic pain .
Literature reviews also showed the efficacy of ALCAR in male infertility, Alzheimer’s disease and depression. ALCAR participation in energy metabolism is purported to positively influence overall spermatogenic process, sperm maturation and sperm motility which may be effective in improving pregnancy rates . Other studies revealed that it can help in treating Alzheimer’s disease through restoring synaptic function and cell membranes, stimulating nerve growth functions, enhancing cholinergic activity, eliminating toxins and restoring brain energy.
Other benefits of ALCAR include HIV infection, diabetic neuropathy and cerebral ischemia management. It also plays a role on various cardiovascular applications as well as improvement on the cognitive performance of chronic alcoholic. There are a handful number of studies demonstrating the efficacy and safety of ALCAR in in humans.