Medically Reviewed by Jennifer Robinson, MD on March 17, 2023
3 min read

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.

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.

Alcoholism. ALC may help reduce cravings 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. ALC has been used to affect certain behaviors in boys with fragile X, such as their social skills and hyperactivity, but research is mixed as to whether it really helps or not.

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

Sciatica. Research has linked ALC with less pain or less intense pain in people with pain from sciatica.

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 and length of treatment have not been established for any condition. Quality and active ingredients in supplements may vary widely from maker to maker. This makes it difficult to establish a standard dose.

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

  • Beef, 4 oz cooked - 56-162 mg
  • Chicken, 4 oz cooked - 3-5 mg
  • Milk, 1 cup whole - 8 mg
  • Cheese, 2 oz cheddar - 2 mg

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:

  • Bipolar disease
  • Neuropathy
  • Hypothyroidism
  • Seizures

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

Interactions. Check with your doctor first if you're taking blood-thinning drugs.

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.