When it comes to losing body fat, everyone wants to start with supplementation. Popping a pill seems like the easiest route to leanness. But the reality is that no supplement is effective for optimizing body composition if you don’t get your eating and workouts dialed in.
Once you lay the groundwork with nutrition and training, supplementation might be a good choice to give you the extra edge. Carnitine is one of those supplements, though not for the reason most people think.
Carnitine Prevents Fat Gain
Carnitine is best known as a metabolic nutrient produced in the body that helps the body burn fat. It facilitates the transfer of fatty acids into your cell’s “energy factories” where it can be burned to produce ATP, the energy currency. While it’s never a bad thing to burn more fat, the real body composition benefits come more from how carnitine increases energy expenditure and affects glucose metabolism (1).
This was illustrated in a study from the University of Nottingham in the UK that tested the effect of carnitine supplementation over 12 weeks on body composition, insulin sensitivity, fat burning, and other metabolic markers (2). The study took young active men and divided them into two groups:
- One group was given 1.4 grams of carnitine with 80 grams of carbs twice a day.
- The other group took 80 grams of carbs twice daily without carnitine.
The reason that carnitine is paired with carbs is that insulin is required to “load” the carnitine into the muscle. Of course, you don’t need carbs to raise insulin. Protein sources, especially whey protein, increase insulin. There are also several “insulin-like” substances that have been shown to load nutrients into muscle. These include the herb fenugreek, the antioxidant alpha lipoic acid, and the plant extract D-pinitol, which have been shown to load another performance-nutrient, creatine, into muscle.
Just keep in mind that it’s possible that you can get benefits from carnitine without carbs. Now, when you do consume extra carbs, it’s probable that you’ll gain body fat as was seen in this study: The carb-only group gained 1.9 kg of body fat, whereas the carnitine-carb group gained no fat.
The reason that carnitine kept the men from putting on fat from the added calories is twofold:
First, taking carnitine increased energy expenditure, which is the primary reason that the group gained no fat—they were burning more calories. During a 30-minute easy exercise test, they burned 6 percent more energy, which scientists think is just enough of an increase to counteract the excess energy intake from the carbs.
Second, taking carnitine allowed the men to increase the use of fat for energy, which was revealed during the exercise test when the men increased fat burning by 10 percent.
Other factors that may have helped prevent fat gain were identified through analysis of genes involved in metabolism. The carnitine group improved insulin sensitivity and experienced an improvement in how the body uses glucose. The researchers concluded that by raising the level of muscle carnitine, your body becomes more efficient at processing fuel, which will increase your energy levels. For depressed people or those with diabetes or obesity, carnitine works wonders on motivation and self-initiative, both with training and work-related tasks.
Carnitine Supports Keto Fat Burning
Carnitine is also effective with lower carb or keto diets that provide a higher proportion of their energy from fat. Low-carb diets may deplete carnitine levels because low-carb diets shift the primary metabolic fuel away from glucose to ketones (from fat) (3).
There is a lack of clinical research into the subject, however, anecdotal reports suggest ketone levels improve from carnitine supplementation. One review reported that when children who were using the keto diet to treat epilepsy supplemented with carnitine they improved well-being, energy levels, and seizure control (3).
Carnitine Improves Exercise Performance
Substantial research shows carnitine can help you take your training to the next level and it may be especially well suited for low-carb athletes who are in the process of adapting to training with low glycogen stores (3). In addition to improving your rate of ATP production from fat, carnitine decreases muscle damage, pain, and markers of metabolic stress from high-intensity exercise. You’ll be able to lift more weight, complete more reps, or run faster and longer, but with greater ease.
When professional triathletes supplemented with 2 grams of carnitine twice a day for 6 months, they had a 44 percent decrease in lactate—the byproduct that makes you “feel the burn” and limits performance (4). With less lactate buildup, work capacity increases and training will not feel as physically difficult. Carnitine also protects muscle during training, reducing post-workout muscle soreness and leading to higher rates of protein synthesis that repairs muscle (5, 6). This combination could allow for more frequent, higher quality training, which means you’re effectively combining the principles of frequency and intensity that are associated with positive changes in body composition.
Carnitine Preserves Body Composition With Aging
Just as older adults lose muscle and gain fat, levels of carnitine and other metabolic nutrients are depleted with age (7). Older adults suffer from decreased insulin sensitivity, higher glucose levels, and lower rates of fat burning. Supplementation with carnitine may help reduce fat gain and preserve muscle mass during your twilight years.
In a study of centenarians (over 100 years old), supplementing with 2 grams of carnitine daily improved muscle mass, reduced body fat, and improved mental and physical fatigue (8). Other studies show carnitine supplementation in older adults improves cognitive function, and in men, raises testosterone levels (9, 10). Older men who took carnitine had improvements in symptoms of low testosterone that were comparable to using a prescription testosterone replacement therapy (11). Carnitine also improves androgen receptor number and sensitivity, which means that testosterone is better able to bind with cell receptors to stimulate protein synthesis and repair damaged muscle (12).
Carnitine increases fat burning, raises energy expenditure, and improves how the body handles carbohydrates, making it a great tool for optimizing body composition.
Carnitine may allow you to train harder and more frequently—two factors that correlate with increased muscle mass and better body composition.
Because fat burning is elevated on a keto diet, carnitine supplementation may improve energy levels and well-being when going low-carb.
Carnitine is especially important for older adults who risk losing muscle and gaining fat, which leads to earlier death and higher rates of chronic disease.
Carnitine is supplied in meat, which means that vegetarians or those on plant-based diets may benefit the most from supplementation.
Most studies have shown benefits from taking 2 to 4 grams of carnitine a day. If you’re on a keto diet, or are aiming for fat loss and want to avoid supplemental carbs, take carnitine with whey protein to ensure it loads into the muscle.
For cognitive benefits, try acetyl-l-carnitine, which improves cerebral blood flow and energy metabolism in the brain.
Our Carnitine Synergy is a 3-part carnitine blend that combines the thermogenic green tea extract with the brain support amino acid acetyl-l-tyrosine to help you take your training to the next level.