Potential Acetyl l Carnitine benefits according to published studies:
Acetyl l carnitine may benefit those with mental fatigue associated with chronic fatigue syndrome.

Patients with multiple sclerosis may benefit from acetyl carnitine, which could reduce their fatigue.

In aging rats, chronic administration of acetyl carnitine increases cholinergic synaptic transmission and consequently enhances learning capacity. The memory of aging rats is rejuvenated by giving them a combination of acetyl l carnitine and alpha lipoic acid.

Acetyl l carnitine may benefit those with diabetic neuropathy. This nutrient could be helpful in chemotherapy induced peripheral neuropathy.

May reduce alcohol-induced cellular damage to organs.

ALCAR may benefit geriatric patients with mild depression.

ALCAR improves the function of mitochondria, the organelles within cells that are involved in energy production.

Is more effective than tamoxifen in the therapy of acute and early chronic Peyronie's disease.

Acetyl l carnitine may benefit individuals with degenerative cerebellar ataxia.

Acetyl carnitine is suitable for clinical use in the reduction of neuronal death after peripheral nerve trauma.

May be helpful in those with Alzheimer's disease. Acetyl l carnitine protects against amyloid-beta neurotoxicity.

Forms of Acetyl l Carnitine
You may come across other forms of acetyl carnitine such as acetyl l carnitine arginate. I am not certain whether acetyl l carnitine arginate offers any advantages over acetyl carnitine or carnitine. Time will tell.

ADHD benefit
L-acetylcarnitine may help with attention deficit hyperactivity disorder (ADHD) in children with the genetic disorder known as fragile X syndrome. Fragile X syndrome results from an inherited genetic defect on the X chromosome. It is associated with  mental retardation and may also cause autism and ADHD, ADHD is common in young boys with fragile X syndrome. Dr. Giovanni Neri from Universita Cattolica in Rome studied boys between 6 and 13 years old for a period one year. Twenty four received l-acetylcarnitine and 27 received placebo. There was a more effective reduction of hyperactivity and improvement of social behavior in patients treated with acetylcarnitine. American Journal of Medical Genetics 2008.

Hypertension and insulin resistance
Ameliorating hypertension and insulin resistance in subjects at increased cardiovascular risk: effects of acetyl-L-carnitine therapy.
Hypertension. 2009 Sep; Mario Negri Institute for Pharmacological Research, Via Gavazzeni 11, Bergamo, Italy.
Insulin resistance, a key component of the metabolic syndrome, is a risk factor for diabetes mellitus and cardiovascular disease. Acetyl-L-carnitine infusion acutely ameliorated insulin sensitivity in type 2 diabetics with insulin resistance. In this sequential off-on-off pilot study, we prospectively evaluated the effects of 24-week oral acetyl-L-carnitine (1 g twice daily) therapy on the glucose disposal rate (GDR), assessed by hyperinsulinemic euglycemic clamps, and components of the metabolic syndrome in nondiabetic subjects at increased cardiovascular risk a priori. Systolic blood pressure decreased. Acetyl-L-carnitine safely ameliorated arterial hypertension, insulin resistance, impaired glucose tolerance, and hypoadiponectinemia in subjects at increased cardiovascular risk. Whether these effects may translate into long-term cardioprotection is worth investigating.

Acetyl l Carnitine Research study
Acetyl-L-carnitine plus propionyl-L-carnitine improve efficacy of sildenafil in treatment of erectile dysfunction after bilateral nerve-sparing radical retropubic prostatectomy.
Urology. 2005 Nov;66(5):1080-5.
Operative Unit of Andrology, Societa Italiana di Medicina della Riproduzione, Bologna, Italy.
To determine whether propionyl-L-carnitine (PLC) plus acetyl-L-carnitine improve the effectiveness of sildenafil in restoring sexual potency after bilateral nerve-sparing radical retropubic prostatectomy. We analyzed the data from 96 patients who had undergone bilateral nerve-sparing radical retropubic prostatectomy: 33 were given placebo (group 1), 32 used PLC 2 g/day plus acetyl-l-carnitine 2 g/day plus sildenafil 100 mg when needed (group 2), and 35 used sildenafil alone (group 3). Placebo proved ineffective and sildenafil and sildenafil plus acetyl-l-carnitine and PLC proved effective. The International Index of Erectile Function-15 scores of the group 2 patients were significantly greater than those of group 3 in the following domains: erectile function, sexual intercourse satisfaction, orgasm, and general sexual well-being. The drugs did not significantly modify the score in the sexual desire domain or in the peak systolic velocity or end-diastolic velocity of the cavernosal arteries. Acetyl-l-carnitine plus propionyl-L-carnitine did not significantly improve the side effects of sildenafil. Propionyl-L-carnitine and acetyl-l-carnitine proved to be safe and reliable in improving the efficacy of sildenafil in restoring sexual potency after bilateral nerve-sparing radical retropubic prostatectomy.

Placebo-controlled double-blind randomized trial on the use of L-carnitine, L-acetylcarnitine, or combined L-carnitine and L-acetylcarnitine in men with idiopathic asthenozoospermia. Fertility & Sterility 2005 Sep;84(3):662-71.
To evaluate the effectiveness of L-carnitine or L-acetyl-carnitine or combined carnitine and acetyl carnitine treatment in improving semen kinetic parameters and the total oxyradical scavenging capacity in semen. Sixty infertile men, ages 20 to 40 years, with the following baseline sperm selection criteria: concentration > 20 x 10(6)/mL, sperm forward motility < 50%, and normal sperm morphology > 30%; 59 patients completed the study. Patients underwent a double-blind therapy of carnitine 3 g/d, acetylcarntine 3 g/d, a combination of carnitine 2 g/d and ALCAR1 g/d, or placebo. The study design was 1 month of run in, 6 months of therapy or placebo, and 3 months of follow-up evaluation. Sperm cell motility increased in patients to whom acetylcarnitine was administered both alone or in combination with carnitine; combined carnitine + acetyl-l-carnitine therapy led to a significant improvement of straight progressive velocity after 3 months. The total oxyradical scavenging capacity of the semen toward hydroxyl and peroxyl radicals also increased and was positively correlated with the improvement of kinetic features. Patients with lower baseline values of motility and total oxyradical scavenging capacity of the seminal fluid had a significantly higher probability of responding to the treatment. The administration of carnitine and l-acetylcarnitine is effective in increasing sperm kinetic features in patients affected by idiopathic asthenozoospemia and improves the total oxyradical scavenging capacity of the seminal fluid in the same population.

A pilot study on the effect of acetyl-L-carnitine in paclitaxel- and cisplatin-induced peripheral neuropathy.
Tumori. 2005 Mar-Apr;91(2):135-8.
In addition to bone marrow suppression and renal toxicity, neurotoxicity is a commonly occurring side effect of widely used chemotherapeutic agents like taxanes, cisplatin and vinca alkaloids. The aim of the present exploratory study was to investigate the activity of acetyl-L-carnitine in reversing peripheral neuropathy in patients with chemotherapy-induced peripheral neuropathy. Twenty-seven patients (16 males and 11 females) with paclitaxel and/or cisplatin-induced neuropathy (according to WHO recommendations for the grading of acute and subacute toxic effects) were enrolled. Patients received at least one cisplatin- (n = 5) or one paclitaxel based regimen, or a combination of both. Patients with chemotherapy-induced peripheral neuropathy were treated with acetyl-L-carnitine 1 g/die i.v. infusion over 1-2 hours for at least 10 days. Twenty-six patients were evaluated for response having completed at least 10 days of acetyl-L-carnitine therapy (median, 14 days; range, 10-20). At least one WHO grade improvement in the peripheral neuropathy severity was shown in 73% of the patients. A case of insomnia related to ALC treatment was reported in one patient. Acetyl-L-carnitine seems to be an effective and well-tolerated agent for the treatment of chemotherapy-induced peripheral neuropathy.

Improvement of visual functions and fundus alterations in early age-related macular degeneration treated with a combination of acetyl-L-carnitine, n-3 fatty acids, and coenzyme Q10.
Ophthalmologica. 2005 May-Jun;219(3):154-66.
The aim of this randomized, double-blind, placebo-controlled clinical trial was to determine the efficacy of a combination of acetyl-L-carnitine, n-3 fatty acids, and coenzyme Q10 (Phototrop) on the visual functions and fundus alterations in early age-related macular degeneration (AMD). One hundred and six patients with a clinical diagnosis of early AMD were randomized to the treated or control groups. The primary efficacy variable was the change in the visual field mean defect (VFMD) from baseline to 12 months of treatment, with secondary efficacy parameters: visual acuity (Snellen chart and ETDRS chart), foveal sensitivity as measured by perimetry, and fundus alterations as evaluated according to the criteria of the International Classification and Grading System for AMD. The mean change in all four parameters of visual functions showed significant improvement in the treated group by the end of the study period. In addition, in the treated group only 1 out of 48 cases (2%) while in the placebo group 9 out of 53 (17%) showed clinically significant worsening in VFMD. Decrease in drusen-covered area of treated eyes was also statistically significant as compared to placebo when either the most affected eyes or the less affected eyes were considered. These findings strongly suggested that an appropriate combination of compounds which affect mitochondrial lipid metabolism, may improve and subsequently stabilize visual functions, and it may also improve fundus alterations in patients affected by early age-related macular degeneration.

Acetyl L Carnitine Improves Pain, Nerve Regeneration, and Vibratory Perception in Patients With Chronic Diabetic Neuropathy: An analysis of two randomized placebo-controlled trials.
Diabetes Care. 2005 Jan;28(1):89-94.
We evaluated frozen databases from two 52-week randomized placebo-controlled clinical diabetic neuropathy trials testing two doses of acetyl-l-carnitine : 500 and 1,000 mg/day t.i.d. Data showed significant improvements in sural nerve fiber numbers and regenerating nerve fiber clusters. Nerve conduction velocities and amplitudes did not improve, whereas vibration perception improved in both studies. Pain as the most bothersome symptom showed significant improvement in one study and in the combined cohort taking 1,000 mg acetyl-l-carnitine. These studies demonstrate that acetyl-l-carnitine treatment is efficacious in alleviating symptoms, particularly pain, and improves nerve fiber regeneration and vibration perception in patients with established diabetic neuropathy.

Comparison of the effects of L-carnitine and acetyl L carnitine on carnitine levels, ambulatory activity, and oxidative stress biomarkers in the brain of old rats.
Ann N Y Acad Sci. 2004 Nov;1033:117-31.
L-carnitine and acetyl-L-carnitine are both used to improve mitochondrial function. Although it has been argued that acetyl-L-carnitine is better than l-carnitine in absorption and activity, there has been no experiment to compare the two compounds at the same dose. In the present experiment, the effects of acetyl-L-carnitine and L-carnitine on the levels of free, acyl, and total L-carnitine in plasma and brain, rat ambulatory activity, and biomarkers of oxidative stress are investigated. Aged rats (23 months old) were given acetyl-L-carnitine or L-carnitine at 0.15% in drinking water for 4 weeks. L-carnitine and acetyl-L-carnitine were similar in elevating carnitine levels in plasma and brain. Both increased ambulatory activity similarly. However, acetyl-L-carnitine decreased the lipid peroxidation (malondialdehyde, MDA) in the old rat brain, while L-carnitine did not. ALCAR decreased the extent of oxidized nucleotides (oxo8dG/oxo8G) immunostaining in the hippocampal CA1 and cortex, while L-carnitine did not. Acetyl L carnitine decreased nitrotyrosine immunostaining in the hippocampal CA1 and white matter, while L-carnitine did not. In conclusion, acetyl L carnitine and L-carnitine were similar in increasing ambulatory activity in old rats and elevating carnitine levels in blood and brain. However, acetyl-L-carnitine was effective, unlike L-carnitine, in decreasing oxidative damage, including MDA, oxo8dG/oxo8G, and nitrotyrosine, in old rat brain. These data suggest that acetyl-L-carnitine may be a better dietary supplement than L-carnitine.

Carnitine versus androgen administration in the treatment of sexual dysfunction, depressed mood, and fatigue associated with male aging.
Urology. 2004 Apr;63(4):641-6.
To compare testosterone undecanoate versus propionyl-L-carnitine plus acetyl-L-carnitine and placebo in the treatment of male aging symptoms. A total of 120 patients were randomized into three groups. The mean patient age was 66 years (range 60 to 74). Group 1 was given testosterone undecanoate 160 mg/day, the second group was given propionyl-L-carnitine 2 grams per day plus acetyl-l-carnitine 2 g/day. The third group was given a placebo (starch). Drugs and placebo were given for 6 months. The assessed variables were total prostate-specific antigen, prostate volume, peak systolic velocity, end-diastolic velocity, resistive index of cavernosal penile arteries, nocturnal penile tumescence, total and free testosterone, prolactin, luteinizing hormone, International Index of Erectile Function score, Depression Melancholia Scale score, fatigue scale score, and incidence of side effects. The assessment was performed at intervals before, during, and after therapy. 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. Testosterone significantly increased the prostate volume and free and total testosterone levels and significantly lowered serum luteinizing hormone; carnitines did not. No drug significantly modified prostate-specific antigen or prolactin. Carnitines and testosterone proved effective for as long as they were administered, with suspension provoking a reversal to baseline values. Only the group 1 prostate volume proved significantly greater than baseline 6 months after testosterone suspension. Placebo administration proved ineffective. Negligible side effects emerged. Testosterone and, especially, carnitines proved to be active drugs for the therapy of symptoms associated with male aging.

Combined treatment with L-carnitine, a popular dietary supplement, and acetylcarnitine, a related chemical, appears to improve sperm motility in men with fertility problems, according to a new study. In the study, 60 infertile men between the ages of 20 and 40 years were randomly selected to take a combination of L-carnitine and L-acetyl-carnitine or an inactive "placebo" for 6 months. In the medical journal Fertility and Sterility, researchers at the University of Rome led by Dr. Andrea Lenzi report that 2 months after the completion of therapy, men who took L-carnitine and L-acetyl-carnitine had increases in sperm concentration, forward movement, and total movement. The most significant improvements in sperm motility, both forward and total, were observed in men who had the lowest levels of moving sperm when the study began. The researchers note that four

Exploratory open label, randomized study of acetyl- and propionylcarnitine in chronic fatigue syndrome.
Psychosom Med. 2004 Mar-Apr;66(2):276-82.
We compared the effects of acetyl-l-carnitine, propionylcarnitine and both compounds on the symptoms of chronic fatigue syndrome (CFS). In an open, randomized fashion we compared 2 g/d acetyl-L-carnitine, 2 g/d propionyl-L-carnitine, and its combination in 3 groups of 30 CFS patients during 24 weeks. Effects were rated by clinical global impression of change. Secondary endpoints were the Multidimensional Fatigue Inventory, McGill Pain Questionnaire, and the Stroop attention concentration test. Scores were assessed 8 weeks before treatment; at randomization; after 8, 16, and 24 weeks of treatment; and 2 weeks later. Clinical global impression of change after treatment showed considerable improvement in 59% of the patients in the acetylcarnitine group and 63% in the propionylcarnitine group, but less in the acetylcarnitine plus propionylcarnitine group (37%). Acetylcarnitine significantly improved mental fatigue (p =.015) and propionylcarnitine improved general fatigue. Attention concentration improved in all groups, whereas pain complaints did not decrease in any group. Two weeks after treatment, worsening of fatigue was experienced by 52%, 50%, and 37% in the acetylcarnitine, propionylcarnitine, and combined group, respectively. In the acetylcarnitine group, but not in the other groups, the changes in plasma carnitine levels correlated with clinical improvement. Acetylcarnitine and propionylcarnitine showed beneficial effect on fatigue and attention concentration. Less improvement was found by the combined treatment. ALCAR had main effect on mental fatigue and propionylcarnitine on general fatigue.

Comparison of the effects of acetylcarnitine and amantadine for the treatment of fatigue in multiple sclerosis: results of a pilot, randomised, double-blind, crossover trial.
J Neurol Sci. 2004 Mar 15;218(1-2):103-8.
Treatment with Acetylcarnitine has been shown to improve fatigue in patients with chronic fatigue syndrome, but there have been no trials on the effect of Acetylcarnitine for treating fatigue in multiple sclerosis (MS). To compare the efficacy of Acetyl carnitine with that of amantadine, one of the drugs most widely used to treat MS-related fatigue, 36 MS patients presenting fatigue were enrolled in a randomised, double-blind, crossover study. Patients were treated for 3 months with either amantadine (100 mg twice daily) or Acetylcarnitine (1 g twice daily). After a 3-month washout period, they crossed over to the alternative treatment for 3 months. Patients were rated at baseline and every 3 months according to the Fatigue Severity Scale (FSS), the primary endpoint of the study. Secondary outcome variables were: Fatigue Impact Scale (FIS), Beck Depression Inventory (BDI) and Social Experience Checklist (SEC). Six patients withdrew from the study because of adverse reactions (five on amantadine and one on acetylcarnitine). Statistical analysis showed significant effects of Acetyl carnitine compared with amantadine for the Fatigue Severity Scale. There were no significant effects for any of the secondary outcome variables. The results of this study show that Acetylcarnitine is better tolerated and more effective than amantadine for the treatment of MS-related fatigue.

Effects of acetylcarnitine in Alzheimer's disease patients unresponsive to acetylcholinesterase inhibitors.
Curr Med Res Opin. 2003;19(4):350-3.
Acetylcarnitine is a compound acting as an intracellular carrier of acetyl groups across inner mitochondrial membranes. It also appears to have neuroprotective properties and it has recently been shown to reduce attention deficits in patients with Alzheimer's disease (AD) after long-term treatment. We performed an open study to evaluate the effect of Acetylcarnitine (2 g/day orally for 3 months) in association with donepezil or rivastigmine in 23 patients with mild AD who had not responded to treatment with acetylcholinesterase inhibitors (AChE-I). Clinical effects were evaluated by assessing cognitive functions, functional status and behavioural symptoms. The response rate, which was 38% after AChE-I treatment, increased to 50% after the addition of Acetylcarnitine, indicating that the combination of these two drugs may be a useful therapeutic option in AD patients. These data do not permit a conclusion as to the possible mechanism of action of the association of the two treatments.

Acetyl-L-carnitine in the treatment of diabetic neuropathy. A long-term, randomized, double-blind, placebo-controlled study.
De Grandis D, Minardi C. Department of Neuroscience, Ospedale Civile, Rovigo, Italy.
Drugs R D. 2002;3(4):223-31.
To assess the efficacy and tolerability of acetylcarnitine versus placebo in the treatment of diabetic neuropathy, mainly by evaluating the effects of treatment on electrophysiological parameters and pain symptoms. This was a multicentre, randomised, double-blind, placebo-controlled, parallel-group study. 333 patients meeting clinical and/or neurophysiological criteria for diabetic neuropathy were enrolled. Patients were randomised to treatment with acetyl-L-carnitine or placebo. Acetylcarnitine (or placebo) was started intramuscularly at a dosage of 1000 mg/day for 10 days and continued orally at a dosage of 2000 mg/day for the remainder of the study (355 days). The main efficacy parameter was the effect of treatment on 6- and 12-month changes from baseline in nerve conduction velocity (NCV) and amplitude in the sensory (ulnar, sural and median) and motor (median, ulnar and peroneal) nerves. The effect of treatment on pain was also evaluated by means of a visual analogue scale (VAS). Among the 294 patients with impaired electrophysiological parameters at baseline, those treated with LAC showed a statistically significant improvement in mean NCV and amplitude compared with placebo. The greatest changes in NCV (at 12 months) were observed in the sensory sural nerve (7 m/sec in the acetylcarnitine group vs +1.0 m/sec in the placebo group), sensory ulnar nerve (+2.9 vs +0.1 m/sec, respectively) and motor peroneal nerve (+2.7 vs -0.2 m/sec), whereas the greatest changes in amplitude were recorded in the motor peroneal nerve (+2.2 vs +0.1 mV). After 12 months of treatment, mean VAS scores for pain were significantly reduced from baseline by 39% in acetyl-carnitine-treated patients compared with 8% in placebo recipients. acetylcarnitine was well tolerated over the study period. Acetylcarnitine was effective and well tolerated in improving neurophysiological parameters and in reducing pain over a 1-year period. acetyl-l-carnitine is, therefore, a promising treatment option in patients with diabetic neuropathy.

Study of the efficacy and tolerability of L-acetylcarnitine therapy in the senile brain.
Bonavita E. Int J Clin Pharmacol Ther Toxicol 1986 Sep;24(9):511-6.
The aim of this study was to evaluate the efficacy and tolerability of L-acetylcarnitine therapy in the senile brain. The trial was conducted on a double-blind basis, with a total of 40 patients divided into two groups of 20, treated for 40 days with L-acetylcarnitine and placebo, respectively -- the therapeutic regimen being two 500 mg tablets three times daily. Mental parameters of the senile brain were assessed at 0, 20 and 40 days of treatment, while basal and final values were recorded for a number of laboratory tests. Short-term, intensive acetyl l carnitine treatment can determine a significant improvement of the main mental parameters of the senile brain, without incidence of significant side effects.

An anti-aging nutrient combo?
Scientists at the Division of Biochemistry and Molecular Biology, University of California, Berkeley, CA rejuvenated aging rats by giving them a combination of lipoic acid and acetylcarnitine -- two natural chemicals available in health food stores. Lead researcher Dr Bruce Ames, said the results were astonishing: "With the two supplements together, these old rats got up and did the Macarena. The brain looks better, they are full of energy - everything we looked at looks more like a young animal." The animals' memories were also significantly  improved. Both acetyl l carnitine and alpha-lipoic acid are normally found in the body's cells. The two chemicals in combination have a positive impact on  mini-organs within the body's cells called mitochondria. Mitochondria generate energy within the cells, and research has suggested that their deterioration is an important cause of aging. The problem seems to be that the very process of creating energy generates molecules called free radicals, which have a deeply destructive effect on the way cells work. The supplement combination was found to mop up the free radicals in mitochondria.
   Dr. Sahelian says: This is interesting and important preliminary research. It is difficult to predict whether this combination is effective in humans, and if so, how to determine the ideal dose combination. In the meantime, those who wish to supplement prudently with small amounts may consider taking  about 5 to 10 mg of lipoic acid, and 30 to 100 mg of acetyl-l-carnitine. Since these nutrients are not often available over the counter in these small doses, you may need to open the capsules and take a portion.

Various Forms manufactured and provided by Sigma Tau corp:
There are Acetyl L-Carnitine Hydrochloride
Acetyl L-Carnitine Galactarate (US PATENT 5952379)
Acetyl L-Carnitine Arginate Dihydrochloride
Acetyl L-Carnitine Taurinate Hydrochloride
Acetyl L-Carnitine Hydrogen Fumarate
ALCAR L-Leucinate Hydrochloride
Acetyl L-Carnitine L-Ornithine Dihydrochloride
     There has not been enough research with each of these forms of ALCAR to determine which are best for long term human consumption.

Animal Studies
Effect of intraperitoneal acetyl l carnitine on anxiety-like behaviours in rats.
Int J Neuropsychopharmacol. 2004 Sep 20:1-10
Acetyl-L-carnitine is an acetyl derivative of carnitine, an endogenous molecule synthesized in vivo and supplemented by diet (mainly via meat and dairy products). Several parallel, double-blind, placebo-controlled studies have demonstrated that Acetyl-L-carnitine treatment produces beneficial effects in geriatric depression. Since most antidepressants also have anti-anxiety effects we examined whether Acetyl-L-carnitine shows anti-anxiety effects in a rat model of anxiety. Compared to a saline-injected control group, chronic administration of Acetyl-L-carnitine at doses of 10 and 100 mgkg (tested 24 h after the last dose administration) showed no effects, whereas doses of 50 and 75 mgkg significantly reduced anxiety-like behaviours in the elevated plus-maze. Acute ALC (100 mgkg), on the other hand (tested 6 h after administration), demonstrated anxiogenic effects. Our data suggest that chronic Acetyl-L-carnitine administration may produce an inverted U-shaped curve of dose-dependent changes in anxiety-like behaviour. The precise mechanism by which Acetyl-L-carnitine decreases anxiety-like behaviour after peripheral administration remains to be determined.