Leucine and Isoleucine are Essential amino acids that pretty much go hand-in-hand.

Leucine and Isoleucine provide ingredients for the manufacturing of other essential biochemical components in the body, some of which are utilized for the production of energy, stimulants to the upper brain and helping you to be more alert.

Supplements and protein powders such as that contain leucine are used extensively by bodybuilders and other athletes to promote muscle recovery.

Leucine helps with the regulation of blood sugar levels. It assists in the growth and repair of muscle tissue (such as bones, skin and muscles). It aids growth hormone production, wound healing and energy regulation.

Leucine can prevent the breakdown of muscle proteins that sometimes occur after trauma or severe stress. Leucine may also be beneficial for individuals with phenylketonuria. Phenylketonuria is a condition in which the body cannot metabolize the amino acid phenylalanine.


Isoleucine is an essential amino acid and is part of the three “branched chain amino acids” (BCAA) — the other two being leucine and valine. This amino acid cannot be manufactured in the body, and needs to be supplied in the diet and was first isolated in 1904 from fibrin.

If you are taking a supplement of leucine, keep it in balance with the other two branched-chain-amino-acids isoleucine and valine.

Isoleucine, together with the other two branched-chain-amino-acids promote muscle recovery after physical exercise and on its own it is needed for the formation of hemoglobin as well as assisting with regulation of blood sugar levels as well as energy levels. It is also involved in blood-clot formation.

Leucine/Isoleucine in Food

In food, Leucine and Isoleucine are found in protein foods, as well as brown rice, beans, nuts and whole wheat.

Read More: Essential Nutrients