By: Matt Weik, BS, CSCS, CPT, CSN
BCAAs have been all the craze for several years as more and more brands come out with their own amino acid supplement that includes leucine, isoleucine, and valine. And while MuscleSport BCAA Revolution has pretty much solidified its place as a crowd favorite due to its 10:1:1 instantized BCAA complex and mouth-watering flavors, there’s one key aspect of the formula that people seem to overlook.
You’re probably used to seeing a 2:1:1 ratio of BCAAs in various formulas, but what many seem to skip over is the ability for leucine to take control of the situation, flip the switch to activate mTOR, and help you build the muscle you’ve been striving to achieve.
Sure, we could talk specifically about the 10:1:1 ratio in BCAA Revolution, but in this article, we’re going to segregate leucine from the bunch and really put it under the microscope and understand how this particular amino acid can truly help you in your health and fitness journey.
In this article, we are going to dive deeper into the world of leucine and how this crucial amino acid plays a role in increasing mTOR to help you build more lean muscle mass. If you want to build more muscle, you do not want to click off this page. Let’s dive in!
Disclaimer: This article is for informational purposes only and is not meant to treat or diagnose any condition. It is recommended that you speak with your doctor before engaging in any exercise, nutrition, or supplement regimen.
What is Leucine?
Before we dive into things and really get down to the granular level of how leucine increases mTOR, let’s first dig a little deeper into leucine itself.
As mentioned above, leucine is an amino acid and is considered to be the most potent of the three BCAAs we are all used to seeing and using in intra-workout supplements. Leucine also just so happens to be an essential amino acid in that the body cannot produce it on its own and would thereby need to be consumed through the food you eat or the supplements you take.
Related Article: A Closer Look at BCAAs and Whey They Are Essential
Anyone who does a quick search of leucine would find that one of its main roles is to increase protein synthesis and muscle growth by activating what is known as the mammalian target of rapamycin (mTOR). The activation of this pathway is what improves protein synthesis, and it all can be kickstarted by the use of leucine.
Why would this be important? Because if you truly wanted to unlock your full muscle-building potential, you would need something like leucine to help put the key in the lock to open up the muscle growth floodgates. But let’s not downplay the muscle-building process and make it seem like the process is easy and that all you need to do is hit the gym and use leucine. No, it’s not that simple, but it definitely plays a role in the muscle-building and recovery process.
With all this being said, you may ask yourself why you would need to use something like BCAA Revolution if all you truly need to increase mTOR is leucine. Which, that would be a valid question. It’s important to understand that excessive intake of leucine (or any amino acid, for that fact) can disrupt the balance of all the other amino acids necessary for the body to function optimally. Therefore, it’s advantageous to supplement with other amino acids while also putting your focus on leucine.
What are the Benefits of Leucine?
Time to make our way through the thick of the weeds to discover the true power that awaits on the other side of supplementing with a high dose of leucine.
Leucine offers many benefits related to protein synthesis, the ability to amplify muscle growth, and also playing a role in boosting overall health. Below are some of the key benefits you should be aware of to fully understand just how powerful leucine is.
1. Muscle Protein Synthesis
When it comes to stimulating muscle protein synthesis, leucine is the match that ignites the gasoline. When mTOR is activated, you have the ability to enhance overall muscle building and repair to support not only the maintenance of lean muscle tissue but also growth.
2. Muscle Recovery & Repair
Your results will suffer if you aren’t able to properly recover and repair torn-down muscle fibers from training. Leucine can help reduce muscle protein breakdown and promote the growth and regeneration of new muscle fibers.
3. Prevent Muscle Loss
If you were to stop exercising, back off significantly, or are over the age of 30, you risk experiencing muscle loss. One of the hardest pills to swallow is that as you age, you may naturally start to see a decline in muscle mass (also called sarcopenia). By utilizing a supplement with leucine and combining it with some sort of resistance training, you can counteract muscle loss and help preserve your lean muscle mass.
4. Boost Energy Production
An aspect not really talked about much is the fact that leucine can be converted into acetyl-CoA, which is a crucial molecule needed in energy production. What it does is enter into the Krebs cycle (also known as the citric acid cycle), where it helps produce ATP, the body’s primary energy source (also what you use up during intense training sessions).
5. Manage Blood Sugar
Being able to manage and manipulate your blood sugar levels is essential. Leucine can help play a role in glucose metabolism as well as insulin secretion. By improving insulin sensitivity. And enhancing glucose uptake by the muscles, leucine can help you better regulate your blood sugar levels.
6. Reduce Hunger & Appetite
Supplementing with leucine can help you manage your appetite and satiety. By doing so, it may help reduce your overall caloric intake, which can be beneficial for supporting weight loss.
7. Support Immunity
No one has time to get sick, and leucine can help support your immunity. Leucine helps with the synthesis of proteins that are involved in the immune response and can help maintain the integrity of your immune cells.
What is mTOR?
One of the benefits above is that leucine can help increase mTOR. Unfortunately, not many people understand precisely what mTOR is or its purpose.
This protein kinase enzyme is a vital regulator of several cellular functions in your body. It is present in every mammalian cell and is essential for protein synthesis, autophagy (the cellular recycling process), cellular development, as well as your metabolism.
The two different mTOR complexes are mTOR Complex 1 (mTORC1) and mTOR Complex 2 (mTORC2). Each complex performs several tasks and reacts to various cellular impulses.
mTORC1 is primarily responsible for regulating protein synthesis and cell growth. It integrates various signals such as nutrient availability (particularly leucine), energy status (ATP levels), growth factors, and hormonal signals to determine whether the cell has the resources and conditions necessary for growth. When conditions are satisfactory, mTORC1 is activated, promoting anabolic processes like protein synthesis and cell proliferation.
mTORC2 is involved in regulating cell survival, cytoskeletal organization, and (like mTORC1) your metabolism. Overall, mTORC2 is less understood when compared to mTORC1, but it is believed that it is involved in cell growth, proliferation, and insulin signaling.
How Does Leucine Increase mTOR and Help Build Muscle?
After navigating through what leucine is, what mTOR is, and all the benefits associated with both, it’s time to jump into how leucine actually increases mTOR in order to help build lean muscle mass.
Below are some of the steps involved in the process of how leucine goes about turning on mTOR so that you can build muscle:
1. Amino Acid Sensing
The mTOR pathway is incredibly sensitive to amino acid levels, particularly BCAAs and leucine. Inside the cell are specialized protein complexes that act as sensors to detect amino acid availability.
2. Activation of Rheb
One of the critical proteins involved in mTOR activation is Ras homolog enriched in brain (Rheb). When amino acids, such as leucine levels, are sufficient, it activates Rheb.
3. Rheb-Mediated mTORC1 Activation
Activated Rheb then interacts with mTORC1, which stimulates mTORC1 to become fully active.
4. Protein Synthesis Promotion
Active mTORC1 phosphorylates and activates downstream targets involved in protein synthesis, such as the ribosomal protein S6 kinase (S6K) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1). When phosphorylated by mTORC1, these targets stimulate the initiation of translation and enhance the synthesis of new proteins, including those involved in muscle growth and repair.
Important Note
With all this being said and the process laid out, it should be noted that leucine isn’t the only player involved in mTOR activation (although it is the most powerful of them). Other amino acids do come into play to help with cellular signaling pathways that can then support the activation of mTOR but not to the levels that leucine supports mTOR.