Benefits of the amino acid L-Leucine

Benefits of the amino acid L-Leucine

L-leucine is one of the three amino acids that make up the “golden triad” of what are known as branched-chain amino acids (BCAAs), along with isoleucine and valine. You may already know by now that the relevance of their benefits in the field of sport is growing stronger by the day. We tell you all about a substance you should not overlook.

Leucine efects

What is Leucine?

Leucine is an essential amino acid and, as such, cannot be produced by the body, so you have to get it from food or dietary supplements.

It is particularly notable for its ability to maintain blood sugar levels, in addition to the fact that it increases growth hormone production. Combined with isoleucine and valine, it protects and fuels muscles, helping to increase endurance levels and boost energy.

As far as natural sources of leucine are concerned, the most important are those of animal origin, as they are sources of complete proteins. What does this mean? Well, they provide the entire repertoire of amino acids, from essential to non-essential.

It is involved in the processes of building new tissues, as well as a multitude of physiological processes, which are related to different areas: healing, scarring or repair of the aforementioned tissues and even energy production.

What does leucine do in the body?

Within muscle tissue, leucine is the most abundant of the three BCAAs. To understand its importance, it is correct to state that skeletal muscle is made up of almost a third of BCAAs.

Among their main characteristics we can mention that they act as fuel under certain circumstances, such as intense or long-lasting physical exertion.

Once this activity has taken place, the level of BCAAs in blood plasma and muscle mass will decrease.

What is this branched-chain amino acid used for?

It would make little sense to analyse this amino acid without referring in detail to its benefits for the organism or, in other words, what it is used for.

To maintain muscle mass

As with other essential amino acids, L-leucine helps maintain muscle mass and helps preserve muscle tissue. It also tends not to degrade as quickly as others during the ageing process. Add to this the fact that it speeds up the recovery process from muscle injuries and skin damage, and you’ll know why it’s a must-have on your sports supplement list.

As if this were not enough, L-leucine plays a fundamental role in regulating protein synthesis and is crucial for building muscle tissue after intense training. Its concentrations in muscle tissue can be described as high and it helps to preserve muscle tissue degradation during endurance and long-distance training.
Bodybuilders frequently use supplements to ensure they have leucine levels full enough to help prevent tissue catabolism and to help build muscle mass.

Maintaining the stimulus is vital to prevent loss of muscle mass.

To promote weight loss

If your goal is to promote weight loss by helping to increase metabolic rate during exercise, leucine is the supplement for you. Not surprisingly, it helps burn visceral fat, or in other words, the deepest layer of fat in the body that often does not respond to diet and exercise.

Leucine uses

Leucine as an anti-catabolic

When you go on a low-calorie diet because you want to reduce your fat percentage, you will certainly be concerned about the possibility of losing muscle mass while you are in an energy deficit. In essence, there is a risk that you will lose valuable muscle tissue as you continue to engage in physical activity.

Along these lines, introducing leucine into your diet can drastically reduce this muscle catabolism, as proof of its undeniable ability to preserve muscle mass.

To regulate blood sugar

Although it is not the only amino acid that allows you to produce glucose, leucine stands out among the rest for its ability to keep blood sugar levels balanced. It can also substitute for glucose during periods of fasting, a property that seems unattainable for the other amino acids.

In an article published in The Journal of Nutrition, food expert scientist Donald K. Layman pointed out that this is a promising amino acid in the important area of metabolic regulation. Accordingly, he explained how leucine improves glucose and insulin homeostasis via stabilisation of blood glucose levels.

To activate the mTor pathway

The substance in question is a key building block for activating the physiological initiation pathway for constructing new proteins, called mTOR (mammalian target of rapamycin or mammalian target of rapamycin in mammalian cells). What we are talking about is a molecule that acts as an activator or “swtich”, which produces a signal that sets up the whole framework for the synthesis of new proteins.

Sarcopenia Leucine


It involves losing the ability to create new muscle structures and muscle power as we grow old. This issue can significantly condition and affect our health and quality of life.

In the same way, in the event of a fall or other accident, the symptoms are aggravated. Did you know that in these cases a sufficient intake of leucine can improve the response aimed at maintaining muscle tissue?

Why to take L-leucine supplements?

Because taking supplements is an easy way to get L-leucine into your diet. Fortunately, there is a wide variety of presentations, formats and combinations on the market. As you can probably imagine, in most cases you will find it together with the other two branched-chain amino acids, i.e. valine and isoleucine.

In these variegated combinations, leucine is usually present in a higher proportion than valine and isoleucine, the most frequent ratio being 2:1:1, although there are also supplements whose ratio of leucine to the other two branched amino acids is 12:1:1. A good example of the latter is Evobcaa’s from our RawSeries brand, in which the mixture has also been supplemented with L-glutamine.

In this post we are going to focus on those supplements that have leucine as the only ingredient and its presentations.

How to choose the best Leucine

When it comes to making a choice, you need to be clear about which leucine to buy. After all, it is a dietary supplement and you should not go for the first thing you are offered.

Tips for choosing the right L-leucine:

  1. It must be of vegetable origin
  2. It must be obtained through a fermentation process.
  3. It must be GMO-free, i.e. free of genetically modified organisms.
  4. It must be instant, i.e. practically instantaneously dissolving. If it does not meet this requirement, it will be difficult for it to dissolve completely.

The solution? Always opt for a trusted brand that shares this information clearly. This is the only way to make sure you are buying the best possible leucine. Think that it is better to invest a little more in order to invest in a quality product. Don’t overlook the fact that it is your health that you could be compromising.

Be careful! There are brands on the market belonging to other companies that sell leucine without specifying its origin. Avoid these products of dubious origin, as their sources may not be GMO-free, not be of plant origin, and may not be instant.

Reliable leucine

Fermentation and dissolution

Regarding the manufacturing process, it is important to check that the leucine product has been produced by fermentation. The reason?  It is a type of process that improves the preservation of the final product. In addition, it eliminates harmful bacteria and promotes better assimilation and digestion.

Finally, the importance of leucine dissolution cannot be underestimated either. Branched-chain amino acids or BCAAs are hydrophobic, i.e. they repel water.

This is why we have already mentioned that, to avoid the difficulty that might otherwise be involved in mixing leucine with a protein shake or simply with water or any other beverage of your choice, opt for the one marketed under the name “Leucine Instant“, which is the only one that guarantees extraordinary solubility.

  • Highly efficient anabolic formula
  • Designed for an immediate supply of amino acids for the skeletal muscle
  • Improved protein synthesis
  • Reduced protein breakdown

How many types of Leucine are commercially available?

Leucine comes in two main forms, so you can choose one or the other depending on your personal preferences.


In our opinion, it is the most suitable if you intend to mix it with your pre, intra or post-workout shakes. Its users agree that it is easy to take and its price is lower.

Leucine Powder

Leucine Powder by RawSeries.

In tablets or capsules

Are you taking it on its own? If you are not going to combine it with other supplements, leucine in tablet or capsule form is a very practical option. It is also ideal if you are sensitive to strong flavours, as this substance has a bitter taste that is unpleasant to take on its own or mixed with juice, water or any other liquid.

The downside of this option is that you will have to take several capsules to meet your daily requirements and that it costs more, so introducing leucine into your diet in capsule or tablet form will be more expensive than introducing the same amount in powder form.

Leucine Caps

Leucine 500mg by EssentialSeries.

When should we take Leucine?

As a preliminary fact, leucine can be taken, as we have already mentioned, on its own or in combination with the rest of the BCAAs. Whichever option you choose, our recommendation is that you consume it:

  • On an empty stomach before doing physical exercise
  • Along with a source of protein after exercise, such as a protein shake
  • With those meals that have a low protein content

And keep these facts in mind as well:

  • It is a highly efficient anabolic formula
  • Designed for the immediate delivery of amino acids to skeletal muscle
  • Enhances protein synthesis
  • Reduces protein degradation

How to take Leucine?

What is the recommended daily dose of leucine?

According to the experts, the recommended dose of leucine moves between 5 and 10g diaries.

Where can we buy Leucine?

Although there are a multitude of specialised establishments where you can buy leucine, we suggest buy Leucine by RawSeries, which faithfully fulfils each and every one of the quality-related requirements referred to in previous sections.

Foods rich in Leucine

Opting to take leucine supplements does not preclude you from also trying to obtain leucine from the many food sources available to you.

The foods richest in leucine are:


Soya should be one of the essentials in your pantry, as it is one of the legumes that are most widely available to you and which, nutritionally speaking, are the most beneficial of all those you can find on the market.

Soya is not only rich in protein, vitamin K and omega-3 fatty acids, but is also one of the best sources of this amino acid, providing 2.97 g of leucine per 100 g of product.


An extraordinary dietary source of leucine, one whole egg provides 1.09 g of leucine. Worried that eating eggs may raise your cholesterol levels? Then opt to eat only the whites to ensure you get your supply of leucine.

Peanuts source of leucine


What if we told you that peanuts are not only a delicious snack but also one of the foods that contains the most leucine? That’s right, as you’ll get 1.76g of leucine per 100g of product. We know what you’re thinking: peanuts and peanut butter are not known to be the healthiest nutrients in the world because of their high fat content.

However, what you may not know is that experts consider them to be recommended foods to include in your diet because they reduce the risk of coronary heart disease. However, you can’t overdo it, as just a teaspoon or two should be enough to get the benefits


Milk is another source with a lot of natural leucine. 100g of milk has 1.6g of leucine. Drinking low fat or skimmed milk is a good way of increasing the leucine supply of the diet without adding extra fats and calories present in whole milk.

Red Meat

The leucine content in a 100g beef steak will approximately provide 1.75g of leucine. Red meat has more saturated fats than other meats, which is why you should consume it moderately.


Whether in the form of seeds, butter or paste. Sesame provides 1.36 g of leucine per 100 g of product. Sesame seeds are available in many bakery products on top of different products, but you can also use them as an ingredient in salads or soups.


You can use chickpeas to cook soups, salads or you can also eat them alone. They have 1.37g of leucine every 100g.

Foods rich in leucine

Every day, more and more athletes are giving L-leucine a try – will you be the next one?


  1. João A.B. Pedroso, Thais T. Zampieri, and Jose Donato, Jr. (2015). Reviewing the Effects of l-Leucine Supplementation in the Regulation of Food Intake, Energy Balance, and Glucose Homeostasis.
  2. Horstman AMH, Kouw IWK, van Dijk JW, Hamer HM, Groen BBL, van Kranenburg J, Gorissen SHM, van Loon LJC. The muscle protein synthetic response to whey protein ingestion is greater in middle-aged women when compared with men. J Clin Endocrinol Metab. 2018 Nov 12. doi: 10.1210/jc.2018-01734.
  3. Yoshii N, Sato K, Ogasawara R, Nishimura Y, Shinohara Y, Fujita S. Effect of Mixed Meal and Leucine Intake on Plasma Amino Acid Concentrations in Young Men. Nutrients. 2018 Oct 18;10(10). pii: E1543. doi: 10.3390/nu10101543.
    Leucine Review

    Improved Protein Synthesis - 100%

    Improved Recovery - 100%

    Muscle Mass Gain - 99%

    Proven Effectiveness - 100%


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    About Melanie Ramos
    Melanie Ramos
    Melanie Ramos uses the HSN Blog to share the latest information and content, so that all those readers who want to learn.
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