• L-carnitine deficiency. Taking L-carnitine by mouth or by IV is effective for treating L-carnitine deficiency caused by certain genetic diseases or other disorders. It’s approved by the FDA for this use. IV products can only be given by a healthcare provider.

• Chest pain (angina). Taking this by mouth or by IV seems to improve exercise tolerance in people with chest pain. Taking product along with standard treatment also seems to reduce chest pain and improve exercise ability in people with cardiac syndrome X. People with this condition have chest pain but not blocked arteries. IV products can only be given by a healthcare provider.
• Heart failure and fluid build up in the body (congestive heart failure or CHF). Taking it  by mouth or by IV seems to improve symptoms and increase exercise ability in people with heart failure. IV products can only be given by a healthcare provider.
• High levels of cholesterol or other fats (lipids) in the blood (hyperlipidemia). Taking it by mouth or by IV can improve cholesterol and triglyceride levels by a small amount. IV products can only be given by a healthcare provider.
• Kidney failure. The FDA has approved giving it by IV, but not by mouth, for kidney failure. This can only be given by a healthcare provider.
• Conditions in a male that prevent a female partner from getting pregnant (male infertility). Taking it by mouth, alone or together with acetyl-carnitine, increases sperm count and sperm movement in males with fertility problems. Some research shows that this increases the chance of pregnancy.
• Swelling (inflammation) of the heart (myocarditis). Some children who have had diphtheria can develop myocarditis. Taking this product by mouth seems to reduce the risk of myocarditis and death in these children.
• A hormonal disorder that causes enlarged ovaries with cysts (polycystic ovary syndrome or PCOS). Taking carnitine by mouth can increase ovulation and the chance of getting pregnant in people who don’t respond to the medication clomiphene. Also, taking carnitine might help with weight loss and improving blood sugar levels.
• Toxic side effects caused by the drug valproic acid. Toxicity caused by valproic acid seems to be linked with L-carnitine deficiency. Taking carnitine by mouth or by IV can prevent liver toxicity from valproic acid. IV products can only be given by a healthcare provider.

There is interest in using this product for a number of other purposes, but there isn’t enough reliable information to say whether it might be helpful.