L-carnitine’s main job is to transport fat into the mitochondria, the energy factories of our cells, where it is used to produce ATP, our cells’ major form of energy. Without sufficient levels of L-carnitine, fat will not be able to enter the mitochondria to be burned for fuel and will instead be stored as body fat.4 If you want to use fat as fuel as efficiently and effectively as possible, you need L-carnitine.
L-carnitine also enhances carbohydrate utilization. This is especially important in our carb-overloaded diets because all of the excess carbohydrates we eat are converted into and stored as fat. For most of us this happens when we consume more than 150 grams of carbs a day.5 Government recommendations tell us to get between 45 to 65 percent of our total daily calories from carbohydrates, which translates to between 225 and 325 grams each day,6 which most people easily meet or exceed. By enhancing carbohydrate utilization, L-carnitine helps to minimize the damaging effects of consuming high amounts of carbs.
In short, L-carnitine is crucial for energy production in the cells, mitochondrial health, a healthy metabolism, and for converting fat and carbs into energy, helping to maintain a healthy weight.
Where Carnitine Shines: Weight Maintenance, Blood Sugar Control & Healthy Aging
Because of L-carnitine’s intrinsic role in cellular energy production and mitochondrial health, it has been investigated for its potential role in aging, weight maintenance, cardiovascular health, and blood sugar regulation. This is what the research has found.
Weight Loss
Carnitine supplementation has been shown to amplify the body’s ability to burn fat and drop weight. One study involving 12 “slightly overweight” subjects showed that 3 grams of L-carnitine daily for 10 days lead to a significant increase in fat oxidation; this was while following their normal diet and not exercising.7 And a recent meta-analysis of nine randomized controlled trials including 911 subjects concluded that carnitine supplementation results in weight loss. The subjects who took L-carnitine lost significantly more weight and had a greater decrease in body mass index (BMI) overall compared to the controls. The studies included a variety of subjects, including some who were physically active, some who had diabetes, some who were obese, and some with muscle fatigue. No matter the group, those who supplemented with L-carnitine saw benefits, including weight loss, improvements in BMI, and increased energy. Doses of L-carnitine ranged from 1.8 to 4 grams a day.8
Insulin Resistance & Blood Sugar Balance
One way in which L-carnitine helps maintain a healthy weight, in addition to its ability to increase fat burning, may be its ability to improve how the body handles glucose, helping to prevent spikes in blood sugar and decreasing insulin resistance (which can certainly help combat that natural winter switch over to a more insulin-resistant state). In its role in enhancing the body’s use of carbohydrates, L-carnitine also ensures that the glucose produced when we eat carbs is used for energy production, rather than being converted and stored as excess body fat.
In an Italian study of 15 non-obese healthy volunteers and 20 type-2 diabetic patients, an infusion of L-carnitine supported improvements in glucose uptake from the bloodstream in both groups. It also improved insulin resistance and the ability to use glucose as fuel in those with type-2 diabetes. 9 The researchers concluded that L-carnitine helps balance energy metabolism, especially when it is impaired or when the body is under a state of stress. Other research has found similar results with the administration of oral L-carnitine and its ability to increase glucose oxidation and reduce insulin resistance.10 11 12
Improve Energy, Maintain Muscle Mass & Lose Weight
Another area of research where L-carnitine shines is increasing energy production as we age. Energy production in the mitochondria naturally declines with age, impairing energy production and increasing oxidative stress, which causes damage to cells and impairs the healthy functioning of the entire body. One randomized controlled trial investigating the effect of L-carnitine supplementation on physical and mental fatigue in 70 centenarians (100 to 106 years old) found that 2 grams of L-carnitine daily significantly improved both mental and physical fatigue, cognitive function, and reduced fat mass while it increased muscle mass.13
Make Sure to get Enough
L-carnitine is produced in our livers and kidneys, but production slows as we age. Any type of disease state or state of metabolic dysfunction (obesity, diabetes, metabolic syndrome, etc.) will result in low L-carnitine levels. Additionally, suboptimal levels of vitamin C, B6, niacin, or iron (all necessary for the body to produce carnitine)14 will result in inadequate production, and in turn, an inadequate supply of energy. Because dietary sources of carnitine include red meat and other animal foods, vegetarians and vegans are vulnerable to carnitine deficiencies. Doses between 2 and 4 grams have been effectively used in studies.15 16
Power Up Your Heart!
L-carnitine is also good for your heart, especially for anyone with a history of heart issues. Research has found that people with heart muscle damage, such as from a heart attack or heart failure, have low carnitine levels in the body.17 And according to cardiologist Stephen Sinatra, MD, the heart gets 60 percent of its fuel from fat and is especially vulnerable to even slight deficiencies in carnitine.18 Because it is necessary to shuttle fat into the heart’s mitochondria to burn for energy, carnitine provides this important muscle with the fuel it needs to properly function.
One year-long placebo-controlled study investigated the effect of carnitine on patients with a recent diagnosis of myocardial infarction (heart attack). Eighty-one patients were given 4 grams of carnitine daily, in addition to their prescription treatments, while the remaining patients received placebos. Those taking L-carnitine had an improvement in heart rate and blood pressure, and a decrease in anginal attacks and rhythm disorders compared to the control group. There was also a lower mortality rate among those taking L-carnitine (1% compared to 12.5% in the placebo group).19
In a more recent 2017 analysis of 17 randomized controlled trials for chronic heart failure (CHF) treatment including 1,625 patients, researchers concluded that “L-carnitine treatment is effective for CHF patients in improving clinical symptoms and cardiac functions…”20
References
18 Sinatra, Stephen MD. The Sinatra Solution: Metabolic Cardiology. Basic Health Publications, Inc., 2005. Pgs 121-123.
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