Let’s face it: Amino acids are crucial to pretty much every aspect of health. These compounds are the building blocks of proteins, which make up our skin, hair and muscles and perform a variety of functions in the body. When it comes to health, though, some amino acids, like L-carnitine and glycine, stand out from the rest.
Found only in small amounts in certain foods like beef, fish and chicken, it’s safe to say that many of us aren’t getting enough L-carnitine in our diets. Fortunately, it’s also available in capsule, liquid or injection form to help supply a quick and concentrated dose of carnitine.
This superstar supplement has been shown to do everything from enhance athletic performance to bring fat burning to the next level. Here’s what you need to know about this important amino acid and what it can do for you.
L-carnitine is a chemical that is made in the human brain, liver, and kidneys. It helps the body turn fat into energy.
L-carnitine is important for heart and brain function, muscle movement, and many other body processes. The body can convert L-carnitine to other chemicals called acetyl-L-carnitine and propionyl-L-carnitine. But it's not clear whether the benefits of these other carnitines are the same.
L-carnitine is used to increase L-carnitine levels in people whose natural level of L-carnitine is too low. Some people also use L-carnitine for conditions of the heart and blood vessels, serious kidney disease, and many other conditions, but there is no good scientific evidence to support these uses.
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.
1,Chest pain (angina). Taking L-carnitine by mouth or by IV seems to improve exercise tolerance in people with chest pain. Taking L-carnitine 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.
2,Heart failure and fluid build up in the body (congestive heart failure or CHF). Taking L-carnitine 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.
3,High levels of cholesterol or other fats (lipids) in the blood (hyperlipidemia). Taking L-carnitine 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.
4,Kidney failure. The FDA has approved giving L-carnitine by IV, but not by mouth, for kidney failure. This can only be given by a healthcare provider.
5,Conditions in a male that prevent a female partner from getting pregnant (male infertility). Taking L-carnitine by mouth, alone or together with acetyl-L-carnitine, increases sperm count and sperm movement in males with fertility problems. Some research shows that this increases the chance of pregnancy.
6,Swelling (inflammation) of the heart (myocarditis). Some children who have had diphtheria can develop myocarditis. Taking DL-carnitine by mouth seems to reduce the risk of myocarditis and death in these children.
7,A hormonal disorder that causes enlarged ovaries with cysts (polycystic ovary syndrome or PCOS). Taking L-carnitine by mouth can increase ovulation and the chance of getting pregnant in people who don't respond to the medication clomiphene. Also, taking L-carnitine might help with weight loss and improving blood sugar levels.
8,Toxic side effects caused by the drug valproic acid. Toxicity caused by valproic acid seems to be linked with L-carnitine deficiency. Taking L-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 L-carnitine for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.
When used as directed, carnitine can be safe and effective with minimal risk of side effects. Common L-carnitine side effects include stomach pain, nausea, vomiting and diarrhea.
L-carnitine may increase the risk of seizures in those with epilepsy. If you’ve had a seizure before, you should not take carnitine.
Additionally, carnitine may worsen symptoms of hypothyroidism. If you have an underactive thyroid, you should consult with your doctor before taking this amino acid.
When starting carnitine, as with any supplement, it’s best to start with a low dose and increase slowly to assess tolerance. If you experience any negative side effects, be sure to report to your doctor to determine if supplementation is right for you.
Finally, keep in mind that carnitine may enhance fat loss and weight loss for some people, but it should be used in combination with a healthy diet and active lifestyle to see the most results.
Pregnancy: There isn't enough reliable information to know if L-carnitine is safe to use when pregnant. Stay on the safe side and avoid use.
Breast-feeding: Taking L-carnitine is possibly safe when taken by mouth while breast-feeding in the amounts recommended by a healthcare provider. Small amounts of L-carnitine have been given to infants in breast milk and formula with no reported side effects. The effects of large amounts are unknown.
Children: L-carnitine is possibly safe when used appropriately by mouth, short-term. It has been used safely by mouth for up to 6 months.
Underactive thyroid (hypothyroidism): Taking L-carnitine might make symptoms of hypothyroidism worse.
Seizures: L-carnitine seems to make seizures more likely in people who have had seizures before. If you have had a seizure, don't take L-carnitine.
There are several different forms of carnitine available. Here are a few of the most common types:
Acetyl-L-Carnitine: This type of carnitine is thought to benefit brain health and memory and has been processed so that it’s able to easily pass the blood-brain barrier.
L-Carnitine L-Tartrate: This type is often found in sports supplements, thanks to its ability to reduce muscle soreness and boost physical performance.
Propionyl-L-Carnitine: This form helps increase levels of nitric oxide in the body, which dilates the blood vessels to promote better blood flow.
L-Carnitine Fumarate: Preliminary research suggests that this type of carnitine could help support bone health to protect against age-related bone loss.
