Acetyl-L-carnitine: Benefits, Dosage, Contraindications
Other name(s)
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Scientific name(s)
Acetyl-L-carnitine
Family or group:
Pseudovitamins
Indications
Rating methodology
EFSA approval.
Cognitive Decline ✪✪✪✪✪
Acetyl-L-carnitine seems to improve cognitive functions and memory in elderly people with age-related cognitive impairment.
Posologie
Orally
1.5 - 2 g
3 - months
Seniors
Depression ✪✪✪✪✪
An analysis of clinical research conducted in Europe shows that acetyl-L-carnitine (1 to 4 grams per day) moderately reduces depressive symptoms compared to placebo in patients with dysthymia and depression. Acetyl-L-carnitine seems to be more effective in older patients and when used at higher doses.
Posologie
Orally
1 - 4 g
60 - days
Seniors
L-acetylcarnitine in depressed elderly subjects. A cross-over study vs placebo.
Effect of acetyl-L-carnitine on geriatric patients suffering from dysthymic disorders.
Evaluation of the effects of L-acetylcarnitine on senile patients suffering from depression.
Acetyl-L-carnitine and alpha-lipoic acid: possible neurotherapeutic agents for mood disorders?
Diabetic Neuropathy ✪✪✪✪✪
Acetyl-L-carnitine slows neuronal degeneration and promotes the repair of neurons damaged by type 1 and 2 diabetes.
Posologie
Orally
1.5 - 3 g
Adults
Acetyl-L-carnitine improves pain, nerve regeneration, and vibratory perception in patients with chronic diabetic neuropathy: an analysis of two randomized placebo-controlled trials.
L-acetylcarnitine as a new therapeutic approach for peripheral neuropathies with pain.
Effects of acetyl-L-carnitine and methylcobalamin for diabetic peripheral neuropathy: A multicenter, randomized, double-blind, controlled trial.
Fatigue ✪✪✪✪✪
Clinical studies have shown that taking acetyl-L-carnitine at 2 grams twice a day for 180 days reduced physical fatigue by 52% and mental fatigue by 43%, compared to only 4% and 8% respectively in elderly patients treated with a placebo. Post-exercise fatigue is also reduced by 51% in patients treated with acetyl-L-carnitine, compared to only 4% for the placebo.
Posologie
Orally
2 - 2 g
180 - days
Seniors
L-Carnitine treatment reduces severity of physical and mental fatigue and increases cognitive functions in centenarians: a randomized and controlled clinical trial.
Effects of Citric Acid and l-Carnitine on Physical Fatigue.
Acetyl L-carnitine (ALC) treatment in elderly patients with fatigue.
Male Fertility Issues ✪✪✪✪✪
The intake of 1g of acetyl-L-carnitine orally, in combination with 2g of L-carnitine for 3 to 6 months, seems to increase sperm motility in men with infertility. Additionally, taking 500 mg of acetyl-L-carnitine orally, combined with 1 mg of L-carnitine every 12 hours after 2 months of treatment with nonsteroidal anti-inflammatory drugs, seems to increase sperm count and motility in men suffering from infertility due to abacterial prostatovesiculoepididymitis (an inflammation of the prostate, seminal vesicles, and epididymis).
Posologie
Orally
500 - 500 mg
6 - months
Men, Seniors
A placebo-controlled double-blind randomized trial of the use of combined l-carnitine and l-acetyl-carnitine treatment in men with asthenozoospermia.
[Clinical efficacy of combined L-carnitine and acetyl-L-carnitine on idiopathic asthenospermia].
Cinnoxicam and L-carnitine/acetyl-L-carnitine treatment for idiopathic and varicocele-associated oligoasthenospermia.
Alzheimer's Disease ✪✪✪✪✪
Acetyl-L-carnitine is believed to slow the progression of Alzheimer's disease and improve memory, cognitive, and behavioral functions. Its activity may be more effective in patients under 66 years old at the onset of the disease.
Posologie
Oral route
1.5 - 3 g
3 - months
Seniors
Acetyl L-carnitine slows decline in younger patients with Alzheimer's disease: a reanalysis of a double-blind, placebo-controlled study using the trilinear approach.
Long-term acetyl-L-carnitine treatment in Alzheimer's disease.
Clinical and neurochemical effects of acetyl-L-carnitine in Alzheimer's disease.
Double-blind, placebo controlled study of acetyl-l-carnitine in patients with Alzheimer's dementia.
Double-blind parallel design pilot study of acetyl levocarnitine in patients with Alzheimer's disease.
Hepatic encephalopathy ✪✪✪✪✪
Some clinical research has shown that taking acetyl-L-carnitine at a dose of 2 grams twice a day for 90 days reduces mental and physical fatigue and improves certain markers of liver function, compared to placebo, in patients with mild to severe hepatic encephalopathy. However, other clinical studies have shown that taking this same dose of acetyl-L-carnitine improves physical function but not mental function, compared to placebo in patients with mild hepatic encephalopathy.
Posologie
Oral route
2 - 2 g
90 - days
Adults
Acetyl-L-carnitine improves cognitive functions in severe hepatic encephalopathy: a randomized and controlled clinical trial.
Acetyl-L-carnitine reduces depression and improves quality of life in patients with minimal hepatic encephalopathy.
Alcoholism ✪✪✪✪✪
Clinical research has shown that acetyl-L-carnitine, administered at a dose of 1 to 3 grams per day by slow intravenous infusion over 3 to 4 hours for 10 days, followed by 3 grams per day orally for an additional 80 days, reduces smoking cravings, inability to feel pleasure (anhedonia), melancholic symptoms, and extends the time to the first drink, compared to placebo, in alcoholic subjects undergoing withdrawal. Additionally, taking this same dose reduces relapse rates compared to placebo.
Posologie
Oral route
1 - 3 g
80 - days
alcoholic subjects
Properties
Neurological
Animal models have demonstrated that acetyl-L-carnitine increases dopamine levels in specific parts of the brain and can modulate NMDA receptors (NMDA is an amino acid that mimics the action of a neurotransmitter: glutamate). This effect is used to reduce alcohol withdrawal symptoms. Dopaminergic agents and NMDA receptor antagonists may play a significant role in alcohol withdrawal. In humans, acetyl-L-carnitine increases beta-endorphin levels (hormones that act on pain and anxiety and induce relaxation), which may also facilitate alcohol withdrawal.
Usages associés
Bioenergizing
Acetyl-L-carnitine plays an important role in fat burning to produce energy and in the transport of fatty acids across mitochondrial membranes (cell organelle), where they are oxidized and converted into energy.
Usages associés
Fertility Effect
Acetyl-L-carnitine and L-carnitine are present in human sperm and seminal fluid. The levels of acetyl-L-carnitine and the ratio of acetyl-L-carnitine to L-carnitine are lower in sterile sperm samples and poorly mobile spermatozoa. An increase in sperm motility is observed in vitro when acetyl-L-carnitine or L-carnitine is added to the sample. Preliminary research also suggests that acetyl-L-carnitine can increase testosterone production and improve testicular function.
Usages associés
Cognitive Function
Acetyl-L-carnitine plays a role in improving age-related diseases, including fatigue, cognitive failures, Alzheimer's, but it's unclear if acetyl-L-carnitine improves cognition by stimulating brain mitochondrial activity or by making more acetyl groups available for use in acetylcholine synthesis (a neurotransmitter in the brain decreased in many forms of dementia).
Usages associés
Hypoglycemic
The role of carnitine in fat metabolism affects all other cellular energy metabolisms, including carbohydrate combustion. It may, therefore, be linked to glucose metabolism, insulin, and metabolic syndrome (it increases insulin sensitivity).
Hepato-protective
In patients with alcohol-induced cirrhosis, serum L-carnitine levels are sometimes increased, possibly due to increased L-carnitine biosynthesis. In subjects with hepatitis or cirrhosis complicated by hepatic encephalopathy (brain impairment in the case of severe liver failure), acetyl-L-carnitine appears to improve liver enzyme levels, ammonia, urea, prothrombin, and bilirubin.
Usages associés
Safety dosage
Adult from 18 year(s): 500 mg - 2000 mg
Acetyl-L-carnitine has been used safely for a period of up to 33 months, orally. Doses used may vary from 500 mg to 2000 mg per day.
Interactions
Médicaments
Platelet aggregation inhibitors/Anticoagulant: strong interaction
Taking 1 g per day of L-carnitine seems to significantly increase the anticoagulant effects of acenocoumarol (Sintrom*). An increase in INR after taking L-carnitine has been observed. This increase persisted for 10 weeks until L-carnitine was discontinued, when the INR level normalized. This interaction has only been reported with L-carnitine, but theoretically it can occur with acetyl-L-carnitine. The incriminated anticoagulants are: Acenocoumarol (Sintrom*), Warfarin (Coumadin*).
Antibiotics: moderate interaction
Cefditoren pivoxil (Spectracef*), pivampicillin, and pivmecillinam increase urinary excretion of carnitine. Theoretically, losses of acetyl-L-carnitine may also be increased. In the case of short-term treatment, the blood level of carnitine decreases, but tissue levels do not appear to be affected. A treatment lasting 1 to 2 months leads to a decrease in muscular carnitine, and a treatment for 6 months or more results in symptoms of carnitine deficiency. Systematic supplementation with L-carnitine or acetyl-L-carnitine is not necessary unless the treatment is prolonged or the patient has other factors contributing to diminished carnitine reserves.
Valproic acid: moderate interaction
Valproic acid interferes with the biosynthesis of L-carnitine in the liver and forms a valproylcarnitine ester that is excreted in the urine, which reduces the reabsorption of free carnitine. The decrease in L-carnitine is not clinically significant in people taking valproic acid. Risk factors for symptomatic L-carnitine deficiency with valproic acid are: - Age under 2 years, - Severe neurological problem, - Taking antiepileptic drugs, - Ketogenic diet. Some experts recommend supplementation with L-carnitine for those treated with valproic acid and presenting the aforementioned risk factors.
Precautions
Pregnant woman: avoid
Avoid use due to lack of reliable and sufficient information.
Hypothyroidism: avoid
L-carnitine appears to inhibit the activity of thyroid hormones at target tissues. Theoretically, this could occur with acetyl-L-carnitine.
Bipolar disorder: avoid
Acetyl-L-carnitine may increase the risk of mania in patients with bipolar disorder.
Epilepsy: avoid
An increase in the frequency or severity of seizures has been reported in patients who have already used L-carnitine orally or intravenously. Theoretically, this could occur with acetyl-L-carnitine.
Chemotherapy: avoid
The use of acetyl-L-carnitine in patients undergoing taxane-based chemotherapy may increase the symptoms of chemotherapy-induced neuropathy.
Breastfeeding woman: avoid
Avoid use due to lack of reliable and sufficient information.
