Leucine is one of the nine amino acids that are essential to the human body, meaning the body requires it to function but can’t synthesize it on its own.1 Leucine is available in many different foods, with some of the best sources being dairy products like milk, cheese, and whey protein.2 Leucine is structurally similar to isoleucine and valine, which are both amino acids with branched side chains.3 These three amino acids work together in the body to carry out a variety of important functions.3
Leucine Uses and Health Benefits
Among leucine benefits, it’s known to contribute to metabolic functions and protein synthesis.1 It also helps with regulating blood-sugar levels and growth hormone production.1 One of the most prominent leucine benefits is its ability to assist in healing bones, skin, and muscle tissue, making it a great nutrient to add to your diet following surgery.3 As an amino acid used in building muscle, leucine has also been praised in the fitness industry.2
Leucine may also help people suffering from phenylketonuria, which is a genetic disorder characterized by the inability to create the enzyme needed to break down the amino acid phenylalanine, causing it to build up in your body.1, 4 Other leucine uses include for:
Leucine Side Effects and Precautions
Leucine is essential to the human body and is not considered dangerous. Since it is present in many foods, it’s rare to see leucine deficiencies. If they do occur, however, side effects may include headaches, fatigue, and depression.3 It’s recommended that individuals get leucine through food sources as this won’t produce any leucine side effects.2 However, leucine supplements can be taken, though it’s best to balance these supplements with supplements of valine and isoleucine since these amino acids work together.3
Talk to your doctor about taking leucine supplements if you have a kidney or liver problem as high doses can worsen these types of conditions.3 Intravenous use of leucine can cause insulin resistance and hyperglycemic reactions.2 Do not take leucine supplements before talking to your doctor first.