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Most of the cells in your body contain carnitine, which your liver and kidneys make. Carnitine helps your cells produce energy. Acetyl-L-carnitine (ALC) is a form of carnitine that's available as a supplement.

Why do people take acetyl-l-carnitine?

People have tried to treat many health problems using ALC, including:

Alzheimer's disease. Several studies show improvements or slower declines in mental ability in people with Alzheimer's disease who took ALC.

High blood sugar. Research shows that people with prediabetes had some improvement in their blood sugar levels after taking ALC for 2 months.

Diabetes. Some research shows that ALC can help the body use insulin more efficiently.

Alcoholism. ALC may help improve mental abilities in people who are alcoholic.

Depression. Research found that ALC treatment reduced symptoms of depression in older people. It also improved dysthymia, a milder form of depression, about as well as a common medication.

Fragile X syndrome. This is a genetic problem. Several studies show that ALC may help improve certain behaviors in boys with fragile X, such as their social skills and hyperactivity.

Male infertility. Men taking ALC in some studies had better sperm movement.

Nerve problems. Some people take ALC for nerve problems related to:

  • Diabetes
  • HIV drugs
  • Chemotherapy

Research has linked ALC with less pain or less-intense pain in people with nerve problems from these causes.

Peyronie's disease. This condition causes the penis to curve abnormally. In one study, men who took daily ALC for 3 months had less pain and curving of the penis. The problem also progressed less in the men taking ALC.

Supplement makers suggest varying amounts of this supplement for different purposes. Common dosages range from 1 to 3 grams daily, divided into several doses. But optimal doses have not been established for any condition. Quality and active ingredients in supplements may vary widely from maker to maker. This makes it very hard to establish a standard dose.

Can you get carnitine naturally from foods?

Animal-based foods are good sources of carnitine, including:

  • Beef
  • Chicken
  • Milk
  • Cheese

What are the risks of taking acetyl-L-carnitine?

Side effects. People taking carnitine have reported a number of side effects, including:

Risks. Avoid using carnitine if you're allergic or sensitive to it. Carnitine may not be safe for people with:

  • Peripheral vascular disease
  • High blood pressure
  • Liver cirrhosis
  • Alcoholism
  • Diabetes
  • Kidney failure
  • Digestive problems
  • Risk factors for mental illness
  • Hepatitis C (fatigue may go up)
  • Sleeping problems
  • Breathing problems

Children and pregnant and breastfeeding women should not use carnitine, since its safety is unknown.

Interactions. Check with your doctor first if you're taking:

  • Blood-thinning drugs
  • Beta-blockers
  • Calcium-channel blockers

Carnitine may interact with drugs or supplements that lower blood sugar. It may affect how your body breaks down certain drugs and supplements.

Carnitine may increase the effects of or have other interactions with many drugs. It may also interact with a number of herbs and supplements. Avoid using this supplement with D- or DL-carnitine.

Tell your doctor about any supplements you're taking, even if they're natural. That way, your doctor can check on any potential side effects or interactions with any medications.

WebMD Medical Reference

Reviewed by Melinda Ratini, DO, MS on December 06, 2012

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