Carnitine (L-carnitine) works as an antioxidant to fight free radicals

Overview

Carnitine helps the body turn fat into energy. The body makes it in the liver and kidneys and stores it in the skeletal muscles, heart, brain, and sperm.

Carnitine is found in avocados

Usually, the body makes all the carnitine it needs. However, when the body doesn't make enough or can't transport it into tissues, a supplement may be necessary.  Conditions, such as angina or intermittent claudication, can cause low levels of carnitine in the body, as can some medications.

Carnitine  acts as an antioxidant so may be effective in dealing with many conditions. Antioxidants fight harmful particles in the body known as free radicals, which damage cells and tamper with DNA.

Carnitine seems safe (but may not help much) with fatigue and improving athletic performance. For more serious conditions, a doctor should be consulted before using carnitine.

Health Conditions 

• Angina -- Some evidence shows that carnitine can be used along with conventional treatment for stable angina. Several clinical trials show that L-carnitine and propionyl-L-carnitine can help reduce symptoms of angina and improve the ability of people with angina to exercise without chest pain. Do not self-treat chest pain with carnitine, however.
• Heart attack -- A few studies have found that carnitine may help when used with conventional medicines after a heart attack, but not all studies agree. Some small studies suggest that people who take L-carnitine supplements soon after a heart attack may be less likely to have another heart attack, die of heart disease, have chest pain and abnormal heart rhythms, or develop heart failure. However, other studies have shown no benefit. Treatment with oral carnitine may also improve muscle weakness. Carnitine should be used along with conventional medication under your health care provider supervision.
• Heart failure -- A few small studies have suggested that carnitine (usually propionyl-L-carnitine) can help reduce symptoms of heart failure and improve exercise capacity in people with heart failure. However, more studies are needed to know for sure.
• Peripheral Vascular Disease -- Decreased blood flow to the legs from atherosclerosis or hardening of the arteries (where plaque builds up in the arteries) often causes an aching or cramping pain in the legs while walking or exercising. This pain is called intermittent claudication, and the reduced blood flow to the legs is called peripheral vascular disease (PVD). Several studies show that carnitine can help reduce symptoms and increase the distance that people with intermittent claudication can walk. Most studies have used propionyl-L-carnitine. 
• Diabetic Neuropathy -- Diabetic neuropathy happens when high blood sugar levels damage nerves in the body, especially the arms, legs, and feet, causing pain and numbness. Some small preliminary studies suggest acetyl-L-carnitine may help reduce pain and increase feeling in affected nerves. It is also possible that carnitine can help nerves regenerate. More research is needed.
• Exercise Performance -- Although carnitine is often taken to boost exercise performance, there is no evidence it works.
• Weight Loss -- No scientific evidence exists to show that L-carnitine works for weight loss. Some studies do show that oral carnitine reduces fat mass, increases muscle mass, and reduces fatigue, which may contribute to weight loss in some people.
• Alzheimer's Disease and Memory Impairment -- The evidence is mixed as to whether carnitine is useful in treating Alzheimer's disease. Several early studies showed that acetyl-L-carnitine might help slow down the progression of Alzheimer's disease, relieve depression related to senility and other forms of dementia, and improve memory in the elderly. But larger and better-designed studies found it didn’t help at all. People should take carnitine for Alzheimer's and other forms of dementia only under the supervision of their health care provider.
• Kidney Disease and Dialysis -- Because the kidneys make carnitine, kidney disease could lead to low levels of carnitine in the body. Your health care provider may prescribe carnitine for kidney disease, don't take it without medical supervision.
• Male Infertility -- Low sperm counts have been linked to low carnitine levels in men. Several studies suggest that L-carnitine supplements may increase sperm count and mobility.
• Erectile Dysfunction -- Preliminary studies suggest propionyl-L-carnitine may help improve male sexual function. One study found that carnitine improved the effectiveness of sidenafil (Viagra) in men with diabetes who had not previously responded to Viagra. In another study, a combination of propionyl-L-carnitine and acetyl-L-carnitine improved the effectiveness of Viagra in men who had erectile dysfunction after prostate surgery. More studies are needed.
• Peyronie's Disease -- One study compared acetyl-L-carnitine to the medication tamoxifen in 48 men with this condition. Acetyl-L-carnitine worked better than tamoxifen at reducing pain during sex and reducing the curve of the penis. Acetyl-L-carnitine also had fewer side effects than tamoxifen. More research is needed.
• Hyperthyroidism -- Some research suggests that L-carnitine may help prevent or reduce symptoms of an overactive thyroid, such as insomnia, nervousness, heart palpitations, and tremors. In one study, a small group of people with hyperthyroidism saw these symptoms improve, and their body temperature become normal, when taking carnitine. Researchers think carnitine may work by blocking the action of thyroid hormone, which could be dangerous for people with low thyroid levels. Don’t take carnitine for hyperthyroidism without your doctor’s supervision.

Dietary Sources
Red meat (particularly lamb) and dairy products are the main food sources of carnitine. It can also be found in fish, poultry, tempeh, wheat, asparagus, avocados, and peanut butter.

Available Forms
Carnitine is available as a supplement in a variety of forms.

• L-carnitine: the most widely available and least expensive
• Acetyl-L-carnitine: Often used in studies for Alzheimer's disease and other brain disorders
• Propionyl-L-carnitine: Often used in studies for heart disease and peripheral vascular disease

Avoid D-carnitine supplements. They interfere with the natural form of L-carnitine and may produce unwanted side effects. In some cases, L-carnitine may be taken by prescription or given intravenously by a health care provider.


Source: Carnitine (L-carnitine) | University of Maryland Medical Center http://umm.edu/health/medical/altmed/supplement/carnitine-lcarnitine#ixzz2j2Hel9ep
University of Maryland Medical Center
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