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Acetyl-L-Carnitine

Uses

Acetyl-L-carnitine is similar in form to the amino acid L-carnitine and also has some similar functions, such as being involved in the metabolism of food into energy. The acetyl group that is part of acetyl-L-carnitine contributes to the production of the neurotransmitter acetylcholine, which is required for mental function.

What Are Star Ratings?

This supplement has been used in connection with the following health conditions:

Used for Why
3 Stars
Age-Related Cognitive Decline
1,500 mg daily
Several clinical trials suggest that this supplement delays onset of ARCD and improves overall cognitive function in the elderly

Several clinical trials suggest that delays onset of ARCD and improves overall cognitive function in the elderly. In a controlled clinical trial, acetyl-L-carnitine was given to elderly people with mild cognitive impairment. After 45 days of acetyl-L-carnitine supplementation at 1,500 mg per day, significant improvements in cognitive function (especially memory) were observed. Another large trial of acetyl-L-carnitine for mild cognitive impairment in the elderly found that 1,500 mg per day for 90 days significantly improved memory, mood, and responses to stress. The favorable effects persisted at least 30 days after treatment was discontinued. Controlled and uncontrolled clinical trials on acetyl-L-carnitine corroborate these findings.

3 Stars
Neuropathy
500 to 1,000 mg three times daily
Taking acetyl-L-carnitine can reduce pain in people with diabetic neuropathy, but does not appear to consistently benefit cases of chemotherapy-induced neuropathy.

Acetyl-l-carnitine has been found to reduce diabetic peripheral neuropathy in multiple controlled clinical trials. A meta-analysis included data from four trials: the subjects in three trials had diabetic peripheral neuropathy and those in the fourth trial had peripheral neuropathy due to antiretroviral therapy for HIV. The analysis found a 20.2% greater reduction in pain in people treated with acetyl-l-carnitine compared to placebo.

Findings from trials examining the use of acetyl-l-carnitine for chemotherapy-induced peripheral neuropathy have been mixed: While several uncontrolled trials have reported decreased nerve pain in cancer patients using various chemotherapy agents, others have noted no effect. In one placebo-controlled trial that included 239 patients with chemotherapy-induced neuropathy, those who received 3 grams daily of acetyl-l-carnitine were more likely to have pain reduction and nerve function improvement. Conversely, another placebo-controlled trial that included 409 breast cancer patients treated with a class of chemotherapy agents called taxanes found treatment with acetyl-l-carnitine increased the severity of chemotherapy-induced neuropathy over 24 weeks and this effect persisted more than 1.5 years after the end of treatment.

2 Stars
Alzheimer’s Disease
1 gram taken three times per day
Short-term studies have found that people with Alzheimer’s disease who supplement with acetyl-L-carnitine experience improved memory, enhanced overall performance, and delayed disease progression.

Several clinical trials have found that supplementation delays the progression of Alzheimer’s disease, improves memory, and enhances overall performance in some people with Alzheimer’s disease. However, in one double-blind trial, people who received acetyl-L-carnitine (1 gram three times per day) deteriorated at the same rate as those given a placebo. Overall, however, most short-term studies have shown clinical benefits, and most long-term studies (one year) have shown a reduction in the rate of deterioration. A typical supplemental amount is 1 gram taken three times per day.

2 Stars
Depression
Refer to label instructions
Acetyl-L-carnitine has been shown in several studies to significantly reduce depression symptoms in seniors.

may be effective for depression experienced by the elderly. A preliminary trial found that acetyl-L-carnitine supplementation was effective at relieving depression in a group of elderly people, particularly those showing more serious clinical symptoms. These results were confirmed in another similar clinical trial. In that trial, participants received either 500 mg three times a day of acetyl-L-carnitine or a matching placebo. Those receiving acetyl-L-carnitine experienced significantly reduced symptoms of depression compared to those receiving placebo. At least two other clinical studies of acetyl-L-carnitine for depression in the elderly have reported similar results. The amount typically used is 500 mg three times daily, although one trial used twice that amount.

2 Stars
Down Syndrome
500 mg three times per day
Acetyl-L-carnitine appears to improve visual memory and attention in people with Down syndrome.

is a compound that occurs naturally in the brain and plays a role in the normal functioning of the nervous system. In a preliminary trial, patients with Down syndrome were given 500 mg of L-acetyl-carnitine three times daily for 90 days and were observed to improve in visual memory and attention. Similar improvement was not seen in untreated patients, nor in patients with mental deficiency unrelated to Down syndrome who were also given L-acetyl-carnitine. More research into the effects of L-acetyl-carnitine in people with Down syndrome is needed.

2 Stars
Erectile Dysfunction (L-Carnitine)
2 grams of each daily
In one study, supplementing with the combination of propionyl-L-carnitine (a form of L-carnitine) and acetyl-L-carnitine significantly improved erectile function in elderly men.

In a double-blind study, supplementing with the combination of propionyl-L-carnitine (a form of L-carnitine) and (2 grams of each per day) for six months significantly improved erectile function in elderly men with erectile dysfunction associated with low testosterone levels. Propionyl-L-carnitine and acetyl-L-carnitine were significantly more effective than testosterone treatment.

2 Stars
Fibromyalgia
1,500 mg daily for ten weeks
Supplementing with acetyl-L-carnitine may improve musculoskeletal pain, depression, and general health in people with fibromyalgia.

In a double-blind trial, supplementation with in the amount of 1,500 mg per day for ten weeks was significantly more effective than a placebo in improving musculoskeletal pain, depression, and general health in people with fibromyalgia.

2 Stars
Liver Cirrhosis
2 grams twice a day for 3 months
A double-blind trial suggests that supplementing with acety-l-carnitine may improve mental and neurological function in people whose cirrhosis has impaired function.
In double-blind trials, supplementing with acety-L-carnitine (2 grams twice a day for three months) improved fatigue and various measures of mental and neurological function in people with impaired function (minimal hepatic encephalopathy) due to cirrhosis.
2 Stars
Macular Degeneration (Coenzyme Q10, Fish Oil)
Follow label directions
In one study, supplementing with a proprietary blend of acetyl-L-carnitine, fish oil, and coenzyme Q10 improved visual function in people with macular degeneration.

In a double-blind study, supplementation with a proprietary blend of , omega-3 fatty acids from fish oil, and coenzyme Q10 for 12 months resulted in an improvement in both visual function and in objective findings on eye examination (a decrease in the drusen-covered area on the retina).

2 Stars
Type 1 Diabetes and Diabetic Neuropathy
500 to 1,000 mg three times daily
Taking acetyl-L-carnitine may improve symptoms of diabetic neuropathy.
In a double-blind study of people with diabetic nerve damage (neuropathy), supplementing with acetyl-L-carnitine was significantly more effective than a placebo in improving subjective symptoms of neuropathy and objective measures of nerve function. People who received 1,000 mg of acetyl-L-carnitine three times per day tended to fare better than those who received 500 mg three times per day.
2 Stars
Type 2 Diabetes and Diabetic Neuropathy
500 to 1,000 mg three times daily
Taking acetyl-L-carnitine may improve symptoms of diabetic neuropathy.

In a double-blind study of people with diabetic neuropathy, supplementing with acetyl-L-carnitine was significantly more effective than a placebo in improving subjective symptoms of neuropathy and objective measures of nerve function. People who received 1,000 mg of acetyl-L-carnitine three times per day tended to fare better than those who received 500 mg three times per day.

1 Star
Amenorrhea
Refer to label instructions
Acetyl-L-carnitine may help restore menstruation in some amenorrheic women.

is an amino acid that may have effects on brain chemicals and hormones that control female reproductive hormones. In a preliminary trial, 2 grams daily of acetyl-L-carnitine was given to amenorrheic women who had either low or normal blood levels of female hormones. Hormone levels improved in the women with low initial levels, and half of all the women resumed menstruating within three to six months after beginning supplementation. Controlled trials are needed to confirm these promising results.

1 Star
Male Infertility
Refer to label instructions
Acetylcarnitine may be a useful for treatment of male infertility caused by low quantities of immobile sperm.

L-carnitine is a substance made in the body and also found in supplements and some foods (such as meat). It appears to be necessary for normal functioning of sperm cells. In preliminary studies, supplementing with 3–4 grams per day for four months helped to normalize sperm motility in men with low sperm quality. While the majority of clinical trials have used L-carnitine, one preliminary trial found that (4 grams per day) may also prove useful for treatment of male infertility caused by low quantities of immobile sperm.

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