Acetyl L-Carnitine

Carnitine occurs in two forms, known as D and L. Only L-carnitine is active in the body and is the form found in food.

Carnitine has been used for the following;

Athletic performance
Aging
Cardiovascular and peripheral-arterial disease
Cancer
Type 2 diabetes
HIV and AIDS
End-stage renal disease and hemodialysis
Male infertility

Precautions:

Check with your doctor before taking carnitine if you have the following;

•Peripheral vascular disease
•Hypertension (high blood pressure)
•Alcohol-induced liver disease (cirrhosis)
•Diabetes
•Kidney disease

Side effects of doses of approximately 3 grams/day, carnitine supplements may cause nausea, vomiting, abdominal cramps, diarrhea, and a "fishy" body odor. More rare side effects include muscle weakness in uremic patients and seizures in those with seizure disorders.

Possible Interactions:

Carnitine interacts with antibiotics such as pivampicillin that are used in the long-term prevention of urinary-tract infections. Chronic administration of these antibiotics increases the excretion of pivaloyl-carnitine, which can lead to carnitine depletion.  Blood concentrations of carnitine may be reduced in children treated for convulsions if using phenobarbital, valproic acid, phenytoin, or carbamazepine.

AZT, In a laboratory study, L-carnitine supplements protected muscle tissue against toxic side effects from AZT, a medication used to treat HIV and AIDS. Additional studies are needed to confirm whether L-carnitine would also have this effect in people.

Doxorubicin, Treatment with L-carnitine may protect heart cells against the toxic side effects of doxorubicin, a chemotherapy medication used to treat cancer, without reducing the effectiveness of medication. Always talk to your oncologist before combining any complementary or alternative therapy with chemotherapy.

Isotretinoin, Isotretinoin (Accutane), a strong medication used for severe acne, can cause abnormalities in liver function, measured by a blood test, as well as high cholesterol and muscle pain and weakness. These symptoms are similar to those seen with carnitine deficiency. Researchers in Greece showed that a large group of people who had side effects from isotretinoin got better when taking L-carnitine compared to those who took a placebo.

Valproic acid, the anticonvulsant medication valproic acid may lower blood levels of carnitine and can cause carnitine deficiency. Taking L-carnitine supplements may prevent any deficiency.

References from Office of Dietary Supplements, National Institutes of Health.  For more information on Carnitine visit their site.