Acetyl-L-Carnitine (ALC)
is a naturally occurring form of L-Carnitine, a vitamin-like nutrient
synthesized in the body from the amino acids lysine and methionine. ALC
serves as a transport molecule for "active acetate," which is a source of
fuel for metabolic processes that take place in cells. ALC carries active
acetate (the "Acetyl" portion) directly into the mitochondrion, the cell's
energy-generating structure. Active acetate is used to produce cellular
energy in the form of ATP. Both L-Carnitine and ALC serve as fat carriers.
Unlike L-Carnitine, ALC readily crosses the blood-brain barrier, where it
has specific benefits for brain neurons. When taken orally, ALC has been
shown to increase ALC levels in both blood and cerebrospinal fluid,
demonstrating its uptake in the brain.1
Best Acetyl-L-Carnitine consists of
Biosint™ Acetyl-L-Carnitine, which is manufactured in Italy by the Sigma Tau
company. It is derived from a base of pharmaceutical-grade L-Carnitine
manufactured using an FDA-approved process that fully complies with
international monograph standards for carnitine production. Known as a
global leader in L-Carnitine research, Sigma Tau holds numerous patents for
production of L-Carnitine, and its L-Carnitine derivatives, such as ALC,
which are used in clinical trials.
ALC has been studied for its effect on cognitive
performance and emotional health in the elderly. In a single-blind,
placebo-controlled trial, 481 elderly subjects exhibiting mild memory
impairment improved their scores on a memory test after taking 1500 mg of
ALC a day for 90 days.2 Hospitalized elderly people
taking ALC have shown improvements in mental outlook.3
While ALC is not a treatment or cure
for Alzheimer's disease, double-blind studies suggest it may help slow the
rate at which early-stage Alzheimer's patients deteriorate.4
In particular, ALC seems to benefit short-term memory in these patients.5
Supports biosynthesis of
acetylcholine, a key neurotransmitter for brain and nerve function*
Brain function requires coordinated communication
between brain cells. Brain and nerve cells ("neurons") communicate across
tiny cell-to-cell gaps called "synapses." The passage of an electrical
impulse from one neuron to the next requires a "neurotransmitter." When an
electrical signal arrives at the synaptic junction, the neuron releases a
neurotransmitter into the synapse. The neuron on the other side of the
synapse contains receptors for the neurotransmitter; these receptors bind
the neurotransmitter, triggering a series of chemical events that sends a
new electrical signal down the membrane of the receiving neuron.
Neurotransmitters work together like an orchestra to transmit information
throughout the brain and nervous system.
Acetylcholine is the most abundant
neurotransmitter in the body, regulating activities of vital organs, blood
vessels and communication between nerves and muscles. In the brain,
acetylcholine helps facilitate memory and learning as well as influence
emotions. ALC is structurally similar to acetylcholine, and brain neurons
stimulated by acetylcholine are receptive to stimulation by ALC.6
It has been shown experimentally that ALC supplies acetyl groups for the
biosynthesis of acetylcholine.7 ALC's hypothesized
cholinomimetic (acts like acetylcholine) activity has led researchers to
investigate its effects on mental function and emotional health.8
Helps supply the brain with
energy by improving energetics in the mitochondrion*
The acetyl groups donated by ALC can be used to
synthesize acetyl-CoA, the key substrate for energy metabolism in the
mitochondrion. 9 Acetyl-CoA enters the Krebs cycle,
the mitochondrial mechanism that generates cellular energy in the form of
ATP. ALC easily crosses the blood-brain barrier, allowing it to play
various roles in maintaining brain neuron (nerve cell) function. When
given by oral administration, the concentration of ALC is increased in the
blood and cerebrospinal fluid.10
Stabilizes intracellular
membranes*
ALC was found to improve membrane phospholipid
metabolism in early-stage Alzheimer's patients.11
Phospholipids are structural components of brain cell membranes that
regulate neuron function. ALC donates acetyl groups that can be used to
modify the functional activity of proteins in neuronal membranes.12
ALC thus plays a role in maintaining membrane function. ALC also increases
membrane stability and structural integrity.13
Increases nerve growth factor
production*
The body produces various specialized proteins called
"growth factors" which are essential to growth and repair of tissue. Nerve
Growth Factor (NGF) protects neurons from death, prolonging survival of
neurons in both the central and peripheral nervous systems. It is
theorized that aging of the central nervous system is associated with a
loss of NGF. ALC has shown the ability to reverse age-related decrease in
the binding of NGF to its receptors in neuron membranes.14
Given to aged rats, ALC increases the level and utilization of NGF
in the rats. ALC protects cholinergic neurons (nerve cells stimulated by
acetylcholine) in rats from degeneration due to lack of NGF.15
These results, together with other data from animal studies,
suggest that ALC positively influences NGF activity.16
Has a protective influence on
brain neurons*
Several animal studies have revealed that ALC exerts a
protective effect on neurons. In one experiment, brain cells from rats
exposed to NMDA, a known neurotoxin, were protected by being
simultaneously exposed to ALC.17 Rats injected with
ALC were protected from mortality caused by the neurotoxin MPP+.18
ALC has been shown to raise levels of glutathione, a highly valuable
antioxidant, in isolated mouse brain tissue.19 ALC
prevents buildup of malondyhaldeyde, a marker of lipid peroxidation.20
ALC is also a chelator of iron, which can generate free radicals. It also
reinforces antioxidant mechanisms in the brain.21
As a whole, data from test tube and
animal studies, showing that ALC has a protective, restorative effect on
brain neurons and neuronal energetic processes, suggest that ALC is an
anti-aging nutrient for the brain. This hypothesis is supported by human
studies demonstrating measurable benefits for brain function in elderly
persons taking ALC by oral consumption.
ALC is considered safe and
well-tolerated when consumed orally.
ALC has been administered in doses as high as 3 grams per day for periods of
two to six months, with no reports of serious side effects. Some patients
have experienced occasional mild abdominal discomfort, nausea, skin rash,
restlessness, vertigo and headache. The severity and incidence of these side
effects are reported as minor.22
Scientific References
1. Pettegrew, JW, Levine, J, McClure, RJ. Acetyl-L-carnitine
physical-chemical, metabolic, and therapeutic properties: relevance for its
mode of action in Alzheimer's disease and geriatric depression. Molecular
Psychiatry 2000;5:616-32.
2. Salvioli, G. Neri , M. L-acetylcarnitine treatment of mental decline in
the elderly. Drugs Exptl. Clin. Res. 1994; 20(4):169-76.
3. Tempesta, E, et al. L-acetylcarnitine in depressed elderly subjects. A
cross-over study vs. placebo. Drugs Exptl. Clin. Res. 1987;8(7):417-23.
4. Spagnoli, A et al. Long-term acetyl-L-carnitine treatment in Alzheimer's
disease. Neurology 1991;41:1726-32.
5. Rai, G et al. Double-blind, placebo-controlled study of acetyl-L-carnitine
in patients with Alzheimer's dementia. Curr. Med Res. Opin. 1990;11:638-47.
6. Falchetto, S, Kato, G, Provini, L. The action of carnitines on cortical
neurons. Can J Physiol Pharmacol 1971; 49(1):1:7.
7. Dolezal, V., Tucek, S. Utilization of citrate, acetylcarnitine, acetate,
pyruvate and glucose for the synthesis of acetylcholine in rat brain slices.
J Neurochem 1981;36(4):1323.30.
8. Passeri, M, et al. Mental impairment in aging: selection of patients,
methods of evaluation and therapeutic possibilities of acetyl-L-carnitine.
Int. J. Clin. Pharm. Res. 1988;8(5):367-76.
9. Pettegrew, JW, Levine, J, McClure, RJ. Acetyl-L-carnitine
physical-chemical, metabolic, and therapeutic properties: relevance for its
mode of action in Alzheimer's disease and geriatric depression. Molecular
Psychiatry 2000;5:616-32.
10. Parnetti, L, et al. Pharmacokinetics of IV and oral acetyl-L-carnitine
in multiple dose regimen in patients with senile dementia of Alzheimer type.
Eur. J. Clin Pharmacol 1992;42:89-93.
11. Pettegrew, JW, et al. Clinical and neurochemical effects of acetyl-L-carnitine
in Alzheimer's disease. Neurobiology of Aging 1995;16(1):1-4.
12. Pettegrew, JW, Levine, J, McClure, RJ. Acetyl-L-carnitine
physical-chemical, metabolic, and therapeutic properties: relevance for its
mode of action in Alzheimer's disease and geriatric depression. Molecular
Psychiatry 2000;5:616-32.
13. Arduni, A, et al. Effect of L-carnitine and acetyl-L-carnitine on the
human erythrocyte membrane stability and deformability. Life Sci
1990;47(26):2395-2400.
14. Taglialatela, G, et al. Stimulation of nerve growth factor receptors in
PC12 by acetyl-L-carnitine. Biochem Pharmacol 1992;44(3):577-85.
15. Taglialatela, G, et al. Acetyl-L-carnitine treatment increases nerve
growth factor levels and choline acetyltransferase activity in the central
nervous system of aged rats. Exp Gerontol 1994;29(1):55-56.
16. Pettegrew, JW, Levine, J, McClure, RJ. Acetyl-L-carnitine
physical-chemical, metabolic, and therapeutic properties: relevance for its
mode of action in Alzheimer's disease and geriatric depression. Molecular
Psychiatry 2000;5:616-32.
17. Forloni, G, Angeretti, N, Smiroldo, S. Neuroprotective activity of
acetyl-L-carnitine: studies in vitro. J Neurosci Res 1994;37(1):92-6.
18. Steffen, V, et al. Effect of intraventricular injection of
1-methyl-4-phenylpyridinium: protection by acetyl-L-carnitine. Hum Exp
Toxicol 1995;14(11):865-71.
19. Fariello, RG, et al. Systemic acetyl-L-carnitine elevates nigral levels
of glutathione and GABA. Life Sci 1988;43(3):289-92.
20. Calvani, M, et al. Action of acetyl-L-carnitine in neurodegeneration and
Alzheimer's disease. Ann Ny Acad Sci 1992;663:483-86.
21. Calvani, M, Carta, A. Clues to the mechanism of action of acetyl-L-carnitine
in the central nervous system. Dementia 1991;2:1-6.
22. Zdanowicz, M. Acetyl-L-carnitine's healing potential. Continuing
Education Module. New Hope Institute of Retailing. October, 2001.
*Above statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.
