Leucine or L-leucine is the most abundant amino acid among BCAA – branched-chain amino acids (the other two are Isoleucine and Valine). This type of amino acid is part of muscle composition and is the only type of amino acid that can be used as energy by muscles, causing branched-chain amino acid levels to decrease in both blood and muscles after exercise.
Among the three branched chain amino acids – Leucine, Isoleucine and Valine – leucine is the most effective in maintaining muscle mass because it is converted to glucose faster than the other two. Therefore, it is not surprising that leucine supplementation is one of the most popular among bodybuilders. Leucine also helps promote the health of bones, skin and muscles after trauma, and is recommended to people during recovery from surgeries.
Leucine alone is one of the most important proteins for those who wish to gain muscle. In fact, leucine is one of the 20 amino acids used by our body to produce new proteins. It is part of the group of essential amino acids, that our body does not produce on its own and therefore it is necessary to acquire it through food.
What is L-Leucine used for?
Leucine can be metabolized by the body for energy production when the muscles need rest. Leucine is a ketogenic amino acid, that is, it is not converted to glucose, but to fatty acids or ketone bodies through the degradation of acetyl-CoA or acetoacetate.
Leucine is also very effective in promoting insulin secretion, since it stimulates the pancreas to produce this hormone that is highly anabolic. This makes Leucine an anabolic agent, that is, helps maintain and gain muscle mass. This makes it easy to understand why L-Leucine is one of the amino acids most consumed by bodybuilders.
The benefits of L-Leucine in hypertrophy
Several studies have confirmed the anabolic effect of L-leucine. It has a regulatory effect, either by stimulating the construction of new proteins or by inhibiting their destruction. Some research also shows the ability of this amino acid to build muscle tissue without the presence of fat in it. In addition, several markers used to identify muscle stress, such as protein degradation, have been shown to be reduced when leucine is added.
However, other studies show the opposite side of leucine supplementation. Increasing the dose of this amino acid in the diet has no effect in individuals who are already in advanced training. For example, it shows strength gains during the first four or five weeks with consumption of 1.5 to 3 grams of leucine per day. After that, the response begins to decline and gains are only provided by muscle training.
Supplementation in the Adults
A survey released on the website of the French National Institute of Agronomic Research has shown the various benefits of supplementation with L-Leucine in older individuals.
It turns out that when the human being reaches 40 years there is a loss of balance between synthesis and protein degradation. The body begins to lose muscle mass and this process gives itself a name of sarcopenia. It is responsible for the loss of mobility of many seniors over the years. It is estimated that this loss is 0.5% to 2% per year.
A study of elderly men and women in their 70s who also performed some strength exercise were able to benefit from L-Leucine supplementation. A dose of 3 grams per day resulted in increased strength in these individuals. Another study corroborated the results which also demonstrated the increased strength in the elderly with the use of L-Leucine for 4 weeks.
Sources of Leucine in Foods
Well, it can be easily found in protein supplements like in pure L-Leucine capsules or even in the already known BCAA’s that contain the branched chain with Leucine, Valine and Isoleucine. In Whey Protein it can also be identified in a smaller proportion, about 10% and also in casein and soy supplements with 8 grams for each 100 grams of the product. Following foods are the rich sources of Leucine:
- meat, white or red;
- whole wheat;
How to take leucine through supplements
It is good to remember that if you do not have a balanced diet with foods rich in protein, taking only leucine in isolation and not feed yourself well, will be waste of time and money. Leucine is one of the most important amino acids, but it still needs a balanced diet to achieve the expected gains.
There is still no agreement as to the exact amount of leucine to be ingested per day. In the studies, the doses used always vary from 1.5 to 3 gms per day. Some studies have shown that doses of 2.5 gms per day have been enough to increase protein synthesis. For those who think of consuming a larger dosage, it is important to fractionate the doses as the day passes so as not to overload the renal system.
Prices and where to buy leucine supplement
In a survey carried out on the internet in supplement stores, we found that the average price of the Leucine powder containing 200 gms is from USD 17.00 to USD 64.00.
Side effects and contraindications
No side effects have been reported with the recommended intake of Leucine. This does not mean that consumption without guidance and in excess cannot cause unwanted effects. Diabetics, pregnant women, people with kidney or other diseases should consult their doctor before taking Leucine.