L-carnitine and black coffee can be drunk together. L-carnitine, also known as L-carnitine, is a kind of amino acid that encourages the conversion of fat into energy, which is easily soluble in water and has the effect of helping the oxidative decomposition of fat. More than 20 countries in the world have already added L-carnitine to infant milk powder, which shows its safety, and L-carnitine has no side effects on human body. The main ingredient in black coffee is caffeine, which has certain effect of refreshing the mind. Normally, L-carnitine will not interact with caffeine, and the two together will not produce some toxic and harmful substances that will affect your health. In daily life, if you need to use L-carnitine and black coffee at the same time, you should use them in moderation according to the specific conditions of the individual, and should not use them in excess, so as not to cause discomfort. At the same time, it should be noted that the caffeine in black coffee can increase the nerve excitability, so you should try to avoid drinking too much black coffee before going to bed, so as to avoid difficulties in falling asleep and other undesirable situations.