Acetyl-L-carnitine is an amino acid (a building block for proteins) that is naturally produced in the body. It helps the body produce energy.
Acetyl-L-carnitine is used for a variety of mental disorders including Alzheimer’s disease, age-related memory loss, late-life depression, thinking problems related to alcoholism, and thinking problems related to Lyme disease. It is also used for Down syndrome, poor circulation in the brain, cataracts, nerve pain due to diabetes, nerve pain due to drugs used in the treatment of AIDS, and facial paralysis.
Some men use acetyl-L-carnitine for infertility, symptoms of “male menopause” (low testosterone levels due to aging), and a disease of the penis called Peyronie’s disease.
The body can convert L-carnitine to acetyl-L-carnitine and vice versa. But, no one knows whether the effects of acetyl-L-carnitine are from the chemical itself, from the L-carnitine it can make, or from some other chemical made along the way. For now, don’t substitute one form of carnitine for another.
How does it work?
Acetyl-L-carnitine helps the body produce energy. It is important for heart and brain function, muscle movement, and many other body processes.
Improving memory problems in elderly people.
Improving memory in people who use alcohol excessively. Taking acetyl-L-carnitine seems to improve memory in 30-60 year-old people whose use of alcohol has produced long-term thinking problems.
Reducing nerve pain (neuropathy) caused by diabetes. Acetyl-L-carnitine reduces pain best in people who have not had diabetes for a long time or who have poorly controlled type 2 diabetes.
Treating Peyronie’s disease, a connective tissue disease in men. Acetyl-L-carnitine seems to be more effective than a drug called tamoxifen for reducing pain and slowing worsening of the condition.
Treating male infertility caused by inflammation of some reproductive organs and tissues (prostate, seminal vesicles, and epididymis). Taking acetyl-L-carnitine by mouth, along with L-carnitine for 6 months, seems to increase sperm count and sperm movement. The carnitines are used following 2 months of treatment with non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin.
Treating symptoms of age-related testosterone deficiency (“male menopause”). Taking acetyl-L-carnitine by mouth along with propionyl-L-carnitine seems to help symptoms related to declining male hormone levels. This combination taken for 6 months seems to improve sexual dysfunction, depression, and fatigue in much the same way the male hormone testosterone does.
Improving blood flow to the brain. Administering a single dose of acetyl-L-carnitine intravenously (by IV) seems to produce short-term improvements in blood flow in the brains of people who have poor blood circulation in the brain.
Treating Alzheimer’s disease. Acetyl-L-carnitine is more likely to help those with early-onset Alzheimer’s disease who are less than 66 years of age and have a faster rate of disease progression and mental decline.
Insufficient Evidence for:
Depression. Some research suggests acetyl-L-carnitine might improve mood and decrease depression in elderly people.
Muscle weakness caused by medications taken for HIV disease. Some research suggests acetyl-L-carnitine might help relieve muscle weakness caused by some HIV treatments.
- Down syndrome.
- Thinking problems related to Lyme disease.
- Other conditions.
More evidence is needed to rate the effectiveness of acetyl-L-carnitine for these uses.
Acetyl-L-carnitine is LIKELY SAFE for most adults. It can cause some side effects including stomach upset, nausea, vomiting, and restlessness. It can cause a “fishy” odor of the urine, breath, and sweat.
Special Precautions & Warnings:
Pregnancy and breast-feeding: Not enough is known about the use of acetyl-L-carnitine during pregnancy and breast-feeding. Stay on the safe side and avoid use.
Under-active thyroid (hypothyroidism): There is some concern that acetyl-L-carnitine might interfere with thyroid hormone. Don’t use acetyl-L-carnitine if you have an under-active thyroid.
Seizures: An increase in the number or seriousness of seizures has been reported in people with a history of seizures who have used L-carnitine by mouth or by IV (intravenously). Since L-carnitine is related to acetyl-L-carnitine, there is a concern that this might also occur with acetyl-L-carnitine. If you have ever had a seizure, don’t take acetyl-L-carnitine.
Acenocoumarol (Sintrom) interacts with ACETYL-L-CARNITINE
Acenocoumarol (Sintrom) is used to slow blood clotting. Acetyl-L-carnitine might increase the effectiveness of acenocoumarol (Sintrom). Increasing the effectiveness of acenocoumarol (Sintrom) might slow blood clotting too much. The dose of your acenocoumarol (Sintrom) might need to be changed.
Warfarin (Coumadin) interacts with ACETYL-L-CARNITINE
Warfarin (Coumadin) is used to slow blood clotting. Acetyl-L-carnitine might increase the effects of warfarin (Coumadin) and increase the chances of bruising and bleeding. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.
The following doses have been studied in scientific research:
For Alzheimer’s disease: 1500-4000 mg daily, usually divided into two or three doses during the day.
In age-related memory loss: 1500-2000 mg daily.
For depression in the elderly: 1500-3000 mg daily in divided doses.
For male infertility:
1 gram of acetyl-L-carnitine plus 2 grams of L-carnitine daily.
4000 mg daily has been used to improve sperm function.
For male infertility secondary to abacterial prostatovesiculoepididymitis: acetyl-L-carnitine 500 mg plus carnitine 1 gram every 12 hours has been used following 2 months of treatment with nonsteroidal anti-inflammatory drugs.
For Peyronie’s disease: 1 gram twice daily for 3 months.
For symptoms of age-related testosterone deficiency: 2 grams of acetyl-L-carnitine plus 2 grams of propionyl-L-carnitine daily.
For diabetic neuropathy: 1500 to 3000 mg per day in divided doses.