Acetyl-l carnitine side effects, acetyl-l carnitine vs l carnitine,
acetyl-l carnitine benefits, dosage and weight loss       Reviewed on June 6, 2014   
L-Carnitine is a derivative of lysine. Its name is derived when its was first isolated from carnus in 1905. L-
Carnitine is produced in the liver and kidneys. It is most concentrated in skeletal and heart muscle. L-carnitine
may play an important role in energy production. Under certain conditions, L-carnitine synthesis can not fulfill
the body demand for L-carnitine, making L-carnitine a conditionally essential nutrient. [16]

Marketers prompt l-carnitine supplements allow the users feeling mentally sharper, having more mental
stamina and focus.

Do we need to take l-carnitine supplements?
L-Carnitine is produced in the body from the nutrients lysine, methionine, vitamin C, vitamin B3, vitamin B6, and
iron. Carnitine is classified as an amino acid, it is primarily used to facilitate the transport of long-chain fatty
acids into the mitochondria of cells for energy production. This process provides muscular energy by burning
fat, and also prevents fatty build-up around vital organs. Natural Carnitine is found primarily in red meats, so
vegetarians may need to supplement to ensure healthy levels in their bodies. Most pills are sold in 200 mg to
500 mg.

acetyl-l carnitine vs l carnitine
Acetyl-L-carnitine is similar in form to L-carnitine and also has some similar functions, such as being involved in
the metabolism of food into energy. It occurs naturally in the brain, liver, and kidney. Its levels may decrease
with advancing age. However, because it is not an essential nutrient, true deficiencies do not occur.


acetyl-l carnitine benefits - Brain
L-Carnitine is a naturally occurring compound and a cofactor for the oxidation of fatty acids in mitochondria. It
participates in the control of the mitochondrial acyl-CoA/CoA ratio, peroxisomal oxidation of fatty acids, and the
production of ketone bodies. It plays an important role in diseases associated with metabolic compromise,
especially mitochondrial-related disorders. A deficiency of carnitine may have major deleterious effects on the
CNS. Consequently, L-Carnitine and its esters such as acetyl-L-carnitine poses unique neuroprotective,
neuromodulatory, and neurotrophic properties.

The potential benefits of acetyl-l carnitine on the brain or nervous system have been studied for years. Here
highlights three early interesting studies:

1. Acetyl-l carnitine shows partial protective effects on PC 12 Cells, under the neurotoxicity of MPP:+ [7]
2. Long term use of acetyl-l carnitine may have benefits of slowing down the age-related nerve cell loss in
some rat brain areas. [8]
3. Acetyl-l carnitine was able to reverse age-related deficits of brain mitrochondria of senescent rates. [9]

Recently, acetyl-L-carnitine benefits on brain cells was demonstrated. The neurotoxicity induced by the
mitochondrial inhibitor 3-nitropropionic acid (3-NPA) is associated with a decrease of ATP synthesis and an
increase of free radical production which can lead to apoptosis or necrosis.Researchers from Scientific &
Medical Affairs, Italy, demonstrated the neuroprotection activites of acetyl-l carnitine against 3-NPA-induced
neurotoxicity in PC12, neuron-like rat pheochromocytoma cell line. [B1]

Malaguarnera M and co-workers at University of Catania, Italy, wondered how acetyl-L-carnitine benefits the
cognitive function of patients with severe hepatic encephalopathy. They divided patients into two groups, the 2
groups received either dosage of 2 g acetyl-L-carnitine twice a day (n = 30) or placebo (n = 30) for 90 days.
88% of patients treated with acetyl-L-carnitine vs 72% of patients treated with placebo showed a significant
improvement in EEG. The improvement of cognitive deficits, the reduction of ammonia, and the modification of
EEG in patients treated with acetyl-L-carnitine suggest that acetyl-L-carnitine could represent a new tool in the
treatment of severe hepatic encephalopathy. [B2] It is nice to have a clinical evidence to support the benefit
claim of acetyl-l carnitine.

Acetyl-l carnitine benefits - Memory
Glycogen synthase kinase-3β (GSK-3β) plays a crucial role in memory deficits and tau hyperphosphorylation
as seen in Alzheimer's disease. Jiang X and fellows at Huazhong University of Science and Technology
reported that ventricular co-injection of wortmannin and GF-109203X (WT/GFX) can induce tau
hyperphosophorylation and memory impairment of rats through activation of GSK-3. They also found that
feeding the rats with Acetyl-L-Carnitine (dosage of 50 mg/day·rat, per os) for 2weeks rescued the WT/GFX-
induced spatial memory retention impairment of the rats by antagonizing GSK-3β activation independent of Akt,
PKCζ and Erk1/2. They also found that Acetyl-L-Carnitine arrested microtubule-associated protein tau
hyperphosphorylation at multiple Alzheimer's disease sites in vivo and in vitro. [B3] Let's review acetyl-l benefits
on Alzheimer's Diease.

Acetyl-l carnitine benefits - Alzheimer's Disease
Acetyl-l carnitine is used as a dietary supplement. Acetyl-L-carnitine has been studied with age-related
cognitive decline, Alzheimer's disease, degenerative, cerebellar ataxia, depression (for elderly people) and
male infertility,

The acetyl group that is part of acetyl-L-carnitine contributes to the production of the neurotransmitter
acetylcholine, which is required for mental function. Clinical trials demonstrate that acetyl-L-carnitine may delay
the progression of Alzheimer's disease [
1 ,2 ] and enhances overall performance in some people with
Alzheimer's disease [
3]. Alzheimer's research has been done with the acetyl-L-carnitine form, rather than the L-
carnitine form, of this nutrient.

One trial [
4] has found that acetyl-L-carnitine may be helpful for people with degenerative cerebellar ataxia, a
loss of muscular coordination caused by disease in the cerebellum (the hind part of the brain that controls
muscle tone and balance). Most research involving acetyl-L-carnitine has used dosage of 500 mg three times
per day, though some research has used double this amount [
5]. [However, this amount may be overdose for
some users].

Di Cesare Mannelli L et al at University of Florence, treated Male mice with 100 mg kg(-1) acetyl-l carnitine
daily for 7 days. Repeated acetyl-l carnitine administration increased glial-derived factor artemin levels in
spinal cord, hippocampus, and prefrontal cortex. They proposed a mechanism for the antidepressant property
of acetyl-l carnitine and use of it in depression. [B4]

Acetyl-l carnitine benefits - HIV
Hart AM et al, Royal Free and University College Medical School, Britain, found that Acetyl-l-carnitine treatment
improved symptoms, caused peripheral nerve regeneration and was proposed as a pathogenesis-based
treatment for distal symmetrical polyneuropathy. Note: Nucleoside analogue reverse transcriptase inhibitors
(NRTI) disrupt neuronal mitochondrial DNA synthesis, impairing energy metabolism and resulting in a distal
symmetrical polyneuropathy (DSP), an antiretroviral toxic neuropathy (ATN) that causes significant morbidity in
HIV disease.

Lenzi A et al, University of Rome "La Sapienza", Rome, Italy, discovered that combined treatment with l-
carnitine and l-acetyl-carnitine in a controlled study of efficacy was effective in increasing sperm motility.

acetyl-l carnitine benefits - Attention deficit/hyperactivity disorder (ADHD)
Adriani W et al, Istituto Superiore di Sanita', Italy, assessed the ability of chronic acetyl- l-carnitine (ALC, saline
or 100 mg/kg SC, plus 50 mg/kg orally) to reduce impulsivity in a validated animal model for
ADHD. Their data
suggested that ALC, a drug devoid of psychostimulant properties, might have some beneficial effects in the
treatment of ADHD children.

acetyl-l carnitine benefits - Male aging symptoms
Cavallini G et al, Headquarters of Societa Italiana di Studi di Medicina della Riproduzione, Italy, compared
testosterone undecanoate versus propionyl-L-carnitine plus acetyl-L-carnitine and placebo in the treatment of
male aging symptoms. They found that testosterone and carnitines significantly improved the peak systolic
velocity, end-diastolic velocity, resistive index, nocturnal penile tumescence, International Index of Erectile
Function score, Depression Melancholia Scale score, and fatigue scale score. Carnitines proved significantly
more active than testosterone in improving nocturnal penile tumescence and International Index of Erectile
Function score.

acetyl-l carnitine benefits - Cholesterol
Ruggiero FM et al, University of Bari, Italy, studied the effect of aging and treatment with acetyl-L-carnitine on
the lipid composition of rat plasma and erythrocytes. They found that aging increases the levels of free and
esterified cholesterol. This study provides the first proof that acetyl-L-carnitine probably acts by lowering free
and esterified cholesterol and arachidonic acid (20:4) levels in the plasma.

Nevertheless, Bell FP et al concluded that there was no significant correlation between plasma carnitine (total,
free, or esterified) and body mass, plasma triglycerides, or plasma cholesterol long time ago.

Acetyl-l carnitine weight loss?
Limited studies are found on this topic. Center SA et al at Cornell University have studied the efficacy, safety,
and metabolic consequences of rapid weight loss in privately owned obese cats. However, this study, in
addition of oral administration of L-carnitine, also include a-reduction diet. The dietary formula and described
reducing strategy can safely achieve a 20% weight reduction within 18 weeks in obese cats. [B5] However, I
can draw a conclusion if L-carnitine can help weight loss if there is no diet control.

acetyl-l carnitine side effects
Most supplements have side effects, and most of the side effects occur at high doses. Overdose of the
supplement may lead to restlessness, nausea, insomnia. Users should discuss with their healthcare providers
before taking any supplement.
Drug interaction
On February 25, 2009, James J. Gormley at wrote "....slowing age-associated memory
impairment. Vinpocetine and acetyl-L-carnitine were especially effective, followed by huperzine A; rhodiola;
ginseng and alpha lipoic acid. The least effective compounds were the drugs, Aricept and Nemanda" in his
article. [1A]

Another article entitled "The energy bunny in me" suggests a synergistic combination of Coenzyme Q10
(CoQ10), acetyl L-Carnitine  and alpha lipoic Acid for maintaining healthy mitochondria and optimum energy
levels. Mitochondria are linked to almost every essential process in cells; its health is very important to us.[1B]

A combination of alpha-lipoic acid (LA) and acetyl L-carnitine (ALC) made research headlines recently when it
was given to old lab rats that then began acting like young lab rats. [1C]
Discuss with your doctor before taking any alternative medicine. This article is for
reference only, it is not a medical advice. All rights reserved. Do not copy this article to
other website or blog.

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levocarnitine in patients with Alzheimer's disease. Arch Neurol 1992;49:1137-41. 3. Cucinotta D, Passeri M, Ventura S, et al.
Multicenter clinical placebo-controlled study with acetyl-L-carnitine (LAC) in the treatment of mildly demented elderly patients.
Drug Development Res 1988;14:213-6. 4. Sorbi S, Forleo P, Fani C, Piacentini S. Double-blind, crossover, placebo-controlled
clinical trial with L-acetylcarnitine in patients with degenerative cerebellar ataxia. Clin Neuropharmacol 2000;23:114-8. 5. No
authors listed. Acetyl-L-Carnitine. Altern Med Rev 1999;4:438-41 [review]. [6] Virmani A and Binienda Z (Sigma-tau
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Biochem Biophys Res Commun. 1990 Jul 31;170(2):621-6].  [15] Can J Biochem Cell Biol. 1983 Jun;61(6):328-32] [16] Seim
H. et al, L(-)-Carnitine and its precursor, gamma-butyrobetaine. In. Kramer K et al, eds. Nutraceuticals in Health and Disease
Prevention. new York: Marcel Dekker, Inc.; 2001:217-256. [17] Stillman M et al, Management of chemotherapy-induced
peripheral neuropathy. Curr Pain Headache 2006 Aug;10(4):279-87. [1A] Boost Your Memory with Brain-Boosting
Supplements February 25, 2009. [1B] The energy bunny in me February 15, 2009 [1C]  Key
Nutrients Help Maintain Brain Function throughout Lifetime [B1] Virmani A, Koverech A, Ali SF, Binienda ZK. Acetyl-L-Carnitine
Modulates TP53 and IL10 Gene Expression Induced by 3-NPA Evoked Toxicity in PC12 Cells. Curr Neuropharmacol. 2011
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