L-carnitine, also known as levocarnitine, is a natural-occurring amino acid that our body produces by combining lysine and methionine. Apart from that, we are able to obtain a small amount of L-carnitine by consuming animal products.¹ Those who are on vegetarian diet may need supplemental L-carnitine as they may not be able to obtain adequate L-carnitine due to diet that avoids animal products.There are 4 types of carnitine found naturally in body or foods; namely D-carnitine, acetyl-L-carnitine, propionyl-L-carnitine and L-carnitine L-tartrate. Among those, L-carnitine and acetyl-L-carnitine are the most used forms in formulating supplements.

L-carnitine plays a vital role in optimizing mitochondrial function and energy production; this is because it helps to transport fatty acids to mitochondrion where it can be burnt as energy. Around 98% of L-carnitine is stored in skeletal muscle, a small amount will be stored in liver and blood². L-carnitine helps to transport fatty acids to mitochondria, the power house of cells, to be burned as energy. A meta-analysis showed that obese adults tend to lose 1.3kg more body weight when they are taking L-carnitine along with their weight loss program including limiting caloric intake and regular physical activities³_. L-carnitine supplement seems to be able to aid in weight losing, but a caloric reduction and incorporating exercise must be in the first place when coming into weight losing.

There are also evidences showing long-term supplementation of L-carnitine may improve sport performances. A study shows that taking L-carnitine before endurance exercise able to prolong exhaustion⁴. As an amino acid itself, L-carnitine may improve exercise recovery. L-carnitine able to attenuate exercise-induced increases in plasma markers of purine catabolism (hypoxanthine, xanthine oxidase, and serum uric acid) and circulating cytosolic proteins (myoglobin, fatty acid-binding protein, and creatine kinase) ⁵. These data show that L-carnitine supplementation is effective in assisting recovery from high-repetition exercise.

Possess similar function to coenzyme Q10, L-carnitine may increase muscular oxygenation or in simple increase oxygen supply to your muscle. It is able to attenuate plasma malondealdehyde, a biomarker of membrane damage. This study also mentioned that L-carnitine boosts nitric oxide production, a vasodilator that improve blood production; hence, helping to reduce the discomfort and fatigue after exercise⁶. Besides, some studies reveal that L-carnitine may also increase the production of red blood cells; that play important role in transporting oxygen to all parts of body. A study shows that taking L-carnitine at dose of 500mg per day for 3-month trial; at the end of the study, statistical analysis revealed significant increases in hematocrit and total iron-binding capacity and a decrease in ferritin⁷.

Apart from being a useful sport supplement, taking L-carnitine may provide benefits in controlling non-communicable diseases such as heart diseases and type 2 diabetes mellitus. L-carnitine could improve cardiac ischemia and reperfusion by preventing the accumulation of long-chain acyl-CoA (substance that promotes the production of free radicals by damaged mitochondria); improves the repairing process of damaged membrane phospholipid caused by oxidative damage; inhibits the irregular heartbeats caused by accumulation of long-chain acyl-CoA within cardiac muscles; and lastly L-carnitine reduces ischemia-induced death of myocardial cells and the consequent remodeling of the left ventricle⁸. Hence, L-carnitine maybe effective in improving heart health. L-carnitine supplementation may reduce the symptoms of impaired glucose tolerance and its associated risk factors.