All About Leucine!
This article is All About Leucine – the most anabolic of all amino acids. Muscle growth is the major goal of most bodybuilders, right? Leucine is the primary amino acid that stimulates growth via protein synthesis. In fact, one of the most exciting concepts in sports nutrition that relates to muscle growth is protein synthesis and the role of the BCAA L-Leucine in that process. In this article, we will look at the importance of leucine and also take a look at protein synthesis. Ready? Then let’s get to it!
What Is L-Leucine?
Leucine is one of nine essential amino acids (EAAs) and one of three branched-chain amino acids (BCAAs). It is also considered a ”signaling” amino acid because it directly signals or stimulates the process of protein synthesis. (1)
Protein Synthesis Defined
First of all, what is protein synthesis? Also known as muscle protein synthesis, it can be defined as a biological process that lets individual cells build the proteins specific to those cells. Another way to define it is that it is a direct trigger of repair, recovery, and muscle growth. There are other factors involved but the primary drivers of protein synthesis are your daily protein intake and your workouts. (2, 3)
A Look At Leucine, Protein Synthesis, And mTOR
You may already be familiar with a lot of this information. I’m sure you probably know that protein is made of about 20 amino acids. These are commonly called proteinogenic amino acids,meaning they are involved in the creation of protein. There are many other aminos, and they are commonly called non-proteinogenic, meaning they are not involved in the creation of protein.
In addition, you no doubt also know that, as was suggested earlier, leucine is more important than all the others when it comes to stimulating protein synthesis. In fact, clinical studies suggest that 2.5 – 3 grams of leucine is what is required to stimulate protein synthesis.
Leucine does this by strongly activating the mTOR (mechanistic target of rapamycin) pathway, or the biological switch that turns protein synthesis on. The mTOR pathway is a master growth regulating protein that “senses” nutritional and environmental signals, including resistance exercise. These signals increase the anabolic processes of the body.
But, simply turning on the switch isn’t enough. That’s because your body also needs the 8 other essential amino acids to stimulate and sustain protein synthesis. The EAAs, as important as they are, must be provided by your diet and supplements, the body does not make them. That’s a bit ironic if you think about it, considering their importance.
Along with the 2.5 – 3 gram dose of leucine, clinical studies also suggest that this increase in protein synthesis only lasts about 1.5 hours, and it will continue to dip even in the presence of plenty of protein/amino acids. This is known as the “muscle-full set-point” phenomenon.
What About Resistance Training?
Resistance training (lifting weights primarily but any kind of resistance training) also stimulates protein synthesis. Much like protein/amino acid intake, the increase in protein synthesis from resistance training is short-lived and will decline. This will lead to muscle protein breakdown.
Now, after your workout, you are in the interesting scenario of muscle protein breakdown increasing while protein synthesis is decreasing. However, as soon as you have the post-workout shake you should be drinking right after your workout, you’re supplying your muscles with an instant dose of protein, which restimulates protein synthesis and derails muscle protein breakdown. This is because of the spike in insulin that accompanies drinking protein and carbohydrates.
A Brief Recap
Ok, we have seen that mTOR is stimulated by 2 things:
- Leucine (and the rest of the BCAAs/EAAs)
- The mechanical stress of resistance training
However, as far as training, be sure you’re using the basic compound movements and lifting progressively heavier weights according to the progressive overload principle. Of course, if you wish, you can also increase intensity by pushing to and past failure. Another way to increase intensity is to reduce rest between sets. All of these are examples of progressive overload. Also, do not rush your reps. Make sure you’re using a weight heavy enough to cause you to fail at or near your target reps. Lift explosively on the concentric, lower slowly on the eccentric, and pause in the fully stretched position.
Protein synthesis is also stimulated by:
The natural anabolic hormones in the body, such as testosterone and insulin. (4, 5, 6) There are other factors as well, and we will look at a couple of them in an upcoming section.
Staying In An Anabolic Environment
The idea of “staying in an anabolic environment” is a term you have probably heard. So what does it mean? It simply means keeping your body in a state of positive protein balance (sometimes called positive nitrogen balance, nitrogen is a major component of protein). Protein synthesis takes place only if you have taken in more protein than what’s required to cover the body’s basic functions. This is what it means to stay in an anabolic environment.
We know that, after water, protein is a major component of the body. We also know that protein in the form of amino acids performs hundreds of daily biological processes so you stay alive and can function normally. This means that your body must have enough protein every day.
Despite this, there may not be enough protein left over for muscle growth to take place. Therefore, bodybuilders and any athlete interested in muscle growth and strength must take in more than the typical mainstream recommendations. A common rule of thumb, and what I always suggest, is 1 gram of protein per pound of body weight.
So, to wind up this recap, muscle growth is the rate of protein synthesis that exceeds the rate of protein breakdown. Therefore, the point of this article is to understand leucine and its role in protein synthesis. This knowledge contributes to your ability to stay in an anabolic environment. (7)
Leucine Timing
As we have seen, any time you ingest protein you’re ingesting leucine as well as the rest of the EAAs. This is one of the many reasons you should eat consistent whole-food meals that are high in quality protein. It’s also a good reason to supplement your eating plan with a good protein powder and/or EAA powder.
As far as timing, a protein shake is the best choice first thing in the morning. In fact, I suggest starting each day with a glass of cold water, followed by a protein shake (followed by coffee!)
Protein shakes are also ideal during your day when you can’t make a meal. Believe me, this can happen more than you might think. I’ve shared in the past how I worked in busy retail stores often alone, and that my only recourse was to rely on protein shakes and bars until other employees arrived.
OK, what about when you workout? As many of you know, I advocate ingesting protein with 50% of the day’s carbs (and all simple carbs) in the hours that surround your workout. The actual workout timeframe is also a good time for an intra-workout supplement that contains the EAAs.
Supplement Suggestions
Therefore, for an amino acid powder, I suggest NutraBio EAA Pure. Why? For several reasons. First of all, NutraBio quality is hard to beat. They were one of the pioneers of fully transparent labeling. At a time when most companies used underdosed prop blends, NutraBio clearly listed the amount of every single thing in their products, right down to the flavoring and sweeteners. Of course, this is a good formula that supplies the clinical dose of leucine, and includes hydration and absorption ingredients.
Now, you can also mix in your EAA Pure with your pre-workout. A good pre-workout choice that already includes the BCAAs (but with leucine at a smaller dose than the 2.5-3 grams, so mix in EAA Pure to get leucine up there and add in the other EAAs) is Kaged Muscle Pre-Workout.
Of course, since protein powders also provide the EAAs, you want one that is high in leucine and if possible, a powder that targets protein synthesis with a little more power than normal. Enter Hi-Tech Precision Protein! This is the protein powder you want if you want to maximize the process. Why, you might ask? Simple. Precision Protein was formulated to release leucine in the early phases of protein synthesis.
Aging, Sleep, And Protein Synthesis
Beyond the 3 things mentioned earlier, such things as sleep and your age impact protein synthesis.
Age
Protein synthesis is stronger when you are younger. That seems to be the case with a lot of things in the body, such as hormone production, as one example. Once you reach 30, protein synthesis starts to slow down a little. By the time you’ve reached 65, protein synthesis will have decreased by 16%. This phenomenon is known as “anabolic resistance”. It literally means that your body utilizes protein less efficiently. Pretty much the best way to counteract this is to eat more protein, and choose only premium quality protein foods and powders. (8)
Sleep
Ah, sleep! This can go a long way, as long as you can get a good night’s sleep every night. Unfortunately, if you struggle with insomnia, or just don’t get enough sleep, even for just one night, hormone signaling is severely thrown off course. Typically, that leaves you feeling sluggish, irritable, and more hungry than usual. Being deprived of sleep also has another severe consequence – greater production of cortisol, the catabolic hormone. Among other negative effects, cortisol increases muscle protein breakdown in the body. Therefore, I advise doing your absolute best to get a good night’s sleep every night.
Other Forms Of Leucine – The Latest Advancements!
Not surprisingly, there have been advancements in leucine supplements. As is the case with many supplements, some companies try to come up with a better version. Nothing has really taken the market by storm yet, but one version shows good promise – DL-185 Dileucine, or L-leucyl-L-leucine monohydrate.
So what is DL-185? Well, it’s a dipeptide, and an extremely concentrated form of leucine. Technically, it is a patented ingredient that is made by NNB Nutrition. If you take a look at their website, they will tell you that the human body has a special uptake transporter for dipeptides (or two amino acids that are linked), called PEPT1. This is what allows the high bioavailability of DL-185. Normally speaking, protein and peptides (short chains of amino acids) are broken down by digestive enzymes.
However, bioactive dipeptides such as DL-185 play a major part in human health, which is why the human body has transporters such as PEPT1. This transporter means more efficient absorption of individual amino acids. Ok, so what are the advertised benefits of this ingredient? Improved protein synthesis, enhanced recovery and better prevention of muscle protein breakdown. Of course, as with any supplement, it’s wise to take a serious look at all the facts before determining if this is something you want to try. (9, 10, 11)
Summary
In this article, All About leucine, we have seen how critical this amino acid is to protein synthesis and muscle growth. We’ve also looked at protein synthesis and the factors that affect it. One of those factors is the use of a protein powder and also an EAA powder. So before you hit the gym, take the time to stop by illpumpyouup.com and stock up on your protein and EAAs. Then let’s go train!
References:
- Leucine Health benefits, dosage, safety, side-effects, and more | Supplements – Examine
- What Is Protein Synthesis. (2015, December 27). Retrieved May 02, 2017, from http://www.proteinsynthesis.org/what-is-protein-synthesis/
- Protein synthesis. (n.d.). Retrieved May 02, 2017, from http://medical-dictionary.thefreedictionary.com/protein synthesis
- Norton, L.E. & Layman, D.K. Leucine Regulates Translation Initiation of Protein Synthesis in Skeletal Muscle after Exercise. J. Nutr., 136:533S-537S, February 2006.
- Laplante, M., & Sabatini, D. M. (2009, October 15). MTOR signaling at a glance. Retrieved May 02, 2017, from http://jcs.biologists.org/content/122/20/3589
- Phillips, S., M, Tipton, K. D., Aarsland, A., Wolf, S. E., & Wolfe, R. R. Mixed muscle protein synthesis and breakdown after resistance exercise in humans. (1997) Am. J. Physiol. 273(1 Pt 1): E99-107.
- Laplante, M., & Sabatini, D. M. (2009, October 15). MTOR signaling at a glance. Retrieved May 02, 2017, from http://jcs.biologists.org/content/122/20/3589
- Paulussen, K. J. M., McKenna, C. F., Beals, J. W., Wilund, K. R., Salvador, A. F., & Burd, N. A. (2021). Anabolic Resistance of Muscle Protein Turnover Comes in Various Shapes and Sizes. Frontiers in nutrition, 8, 615849. https://doi.org/10.3389/fnut.2021.615849
- https://dileucine.com/
- Heilier, M. D., et al. (1972), Gut, 13, 965-969.[5]Morifuji, M., et al. (2010). J Agric Food Chem, 58(15), 8788-8797.
- Kerksick, C. M., et al. (2018). J Int Soc Sports Nutr, 15, 38.