Can Leucine Consumption Before Exercise Hinder Performance?

[Mike Arnold]

Can Leucine Consumption Before Exercise Hinder Performance?​

By Michael J. Rudolph, Ph.D​

One of the more well-characterized muscle-building supplements is the branched-chain amino acid leucine, which has clearly been shown to inhibit muscle protein breakdown while simultaneously increasing the rate of muscle protein synthesis, ultimately promoting substantial muscle growth.1 Leucine consumption promotes muscle protein accumulation and muscle growth by activating the extremely important nutrient-sensing molecule mTOR, which directly turns off muscle protein degradation while activating muscle protein synthesis. Several studies have shown mTOR activation by leucine intake specifically during and after resistance exercise.2,3 Although it has been well established that leucine consumption during and after resistance exercise promotes muscle growth, the verdict is still out regarding the performance-enhancing effect from leucine consumption before training. Some of the uncertainty about leucine’s pre-workout consumption stems from the fact that leucine consumption decreases energy production within the muscle cell, potentially diminishing muscle performance during exercise. Another concern about pre-workout leucine consumption involves the likely desensitization of the potent muscle-building hormone insulin, resulting from additional leucine consumed before working out. The final concern involves the negative influence that leucine consumption may have on the central nervous system (CNS) where pre-workout leucine consumption might increase the rate of CNS fatigue, promoting overall sluggishness that decreases exercise performance.




Pre-workout Leucine Decreases Muscle Cell Energy

In order to build muscle, you’d think that you need to be in an anabolic state at all times— which might also make you believe that the ubiquitous consumption of muscle-building compounds, like leucine, should enhance muscle growth. Yet the reality is being constantly in an anabolic state is not optimal for muscle size and strength. This is mainly because maximal muscle growth requires the perfect blend of muscle-building anabolism combined with energy-producing catabolism. In other words, if you want to build muscle, something has to supply them with energy to function. Well, that’s where catabolic processes like glycogenolysis, the breakdown of glycogen into glucose for energy, play a huge role mainly because intense weightlifting requires glucose for energy. So, although leucine potently stimulates muscle growth, it also prevents the breakdown of glycogen into glucose4, reducing available energy that is necessary for muscle contraction. Of course, reduced muscular contraction decreases strength output— which likely compromises the ability to get huge.




Too Much Leucine Diminishes Muscle Growth

Insulin is the most potent muscle-building hormone produced in the human body, possessing the ability to drastically increase muscle protein synthesis and enhance muscle growth.5 Insulin achieves this muscle-building effect by binding to the insulin receptor and setting off a cascade of signaling events that eventually activates the enzyme mTOR, triggering muscle growth.6,7 However, insulin signaling is very sensitive to overstimulation— where too much insulin signaling can rapidly trigger negative feedback mechanisms that turn down insulin-driven muscle growth. In addition to the well-known influence that glucose has on insulin secretion and activity, one of the more potent insulin activators is leucine. Interestingly, several studies have shown that insulin resistance can occur with increased amino acid consumption, especially the branched-chain amino acid leucine.8,9 The exact mechanism by which leucine modulates insulin sensitivity is currently unclear. Although the decreased insulin sensitivity may be associated with greater insulin secretion induced by leucine10,11, potentially inducing insulin resistance. Of course, insulin resistance from too much leucine consumption would reduce all of insulin’s anabolic properties, meaning a decrease in muscle protein accumulation and therefore muscle growth.




Leucine Consumption Before Your Workout Promotes Sluggishness and Fatigue

The CNS, composed of the brain and spinal cord, serves as the main “processing center” for the entire nervous system that controls all the workings of your body. Neurons, or nerve cells, are the core components of the CNS that function to receive and confer all of this body-regulating information by electrical and chemical signaling. Neuronal electrical signaling is ultimately converted at the nerve ending or synapse into chemical signaling utilizing neurotransmitters that diffuse across the synapse to adjacent neurons, triggering further electrical signaling down those neurons, which eventually control numerous processes in the body. Serotonin is a neurotransmitter secreted within the neuronal synapse that induces sleep and drowsiness. Intense exercise has been shown to increase the release of serotonin in the brain, putatively contributing to exercise-induced fatigue. Initially, it was thought that the increase in serotonin alone triggered fatigue. However, it turns out that greater fatigue from exercise is influenced more specifically by an increase in the ratio of serotonin to another neurotransmitter known as dopamine.12 The neurotransmitter dopamine has well-defined roles including increased mental arousal, improved motor control and greater levels of motivation, which all tend to improve exercise performance. Therefore, a lower serotonin to dopamine ratio, by either decreasing performance-inhibiting serotonin or increasing performance-enhancing dopamine, should improve exercise capacity. Interestingly, leucine consumption has been shown to inhibit serotonin production by preventing transport of the serotonin-precursor tryptophan into the brain.13 Because tryptophan is a building block for serotonin, lower tryptophan in the brain reduces serotonin production— suggesting that leucine consumption before exercise could actually mitigate exercise-induced fatigue. On the other hand, a recent study by Choi et al.14 showed that leucine also competitively inhibits dopamine production by preventing the uptake of the dopamine-precursor tyrosine into the brain. Since greater brain dopamine function improves physical performance, the finding that leucine reduces dopamine levels in the brain highlights why leucine consumption, especially before exercise when motivation and energy levels are paramount, may have a detrimental influence on physical performance despite leucine’s ability to also reduce serotonin levels. In conclusion, leucine’s capacity to trigger anabolic processes, such as muscle growth and glycogen production, makes the timing of leucine consumption very important. While leucine consumption during and after lifting weights effectively prevents muscle breakdown while enhancing muscle growth, consuming leucine before your workout appears to have several drawbacks that negatively influence exercise performance— suggesting that pre-workout leucine consumption is not best for optimal muscular performance.

 

[warlock]

Mike, thanks for sharing this article. This is very good to know.

Do you think 5 gr of leucine intra and 5gr post-workout is a decent dose for most? Or would you use 10gr instead?

Would you just keep the leucine intake to mostly intra and pot-workout, or would you supplement with it also at other specific times of the day?

I would love to hear your thoughts if you do not mind

 

[NY Muscle]

Buzz kill! but yeah seems intra is still okay to do or any time of the day except pre workout.

Sent from my SM-N900V using Tapatalk 2

 

[emeric delczeg]

BCAA

Abstract
The higher risk for amyotrophic lateral sclerosis (ALS) among professional soccer players, recently reported in Italy, has stimulated investigations in the search for environmental factors that may be at the origin of the increased susceptibility to the disease. Here we studied if high concentrations of branched-chain amino acids (BCAAs), widely used among athletes as dietary integrators to improve physical performance, may be related to an excitotoxic neuronal cell damage. Our results show that (i) high concentrations of BCAAs are neurotoxic and increase excitotoxicity in cortical neurons; (ii) neurotoxicity is brain area specific, being detected in cortical, but not in hippocampal neurons; (iii) it is related to NMDA receptor overstimulation, since it is abolished in the presence of MK-801, a specific NMDA channel blocker; (iv) it depends on the presence of astrocytes. We describe here a possible biological link between an environmental factor (high dietary intake of BCAAs) and the increased risk of ALS among soccer players.

 

[Mike Arnold]

Thoughts? Here's mine.

Basically, the author implies that leucine's ability to diminish insulin resistance, promote CNS fatigure, and hinder glycogen utilization makes the pre-workout consumption of leucine sub-optimal.

However, before we go any further, allow me to point out that this particular article was written for and posted on the AML (Advanced Molecular Labs) website; a supplement company which makes a pre-worpkout product that does not contain leucine, although the disclaimer does state that the author does not beneft from the sale of AML products.

Although M. Rudolph is correct in stating that leucine does all of these things, I am not convinced that the degree to which they take place outweigh the benefits of pre-workout leucine consumption.

I think it's a bit of stretch to infer that leucine has the ability to impair exercise performance to such a degree that the growth stimulis is inhibited, and especially that this inhibition is of greater significance than the known benefits of pre-workout leucine. I have taken leucine before training many times, and I have never observed even the slightest increase in CNS fatigue, nor any impairment in my ability to initiate muscle contraction--either in terms of maximal strength or in the number of repetitions I am able to perform.

If leucine's negative effects on glycogen utilization and CNS function are so subtle that they are not even percievable from a peformance standpoint, then one must wonder how much of an effect it is really having on our ability to stimulate growth during training. My guess is not much--and maybe not at all. At any rate, I have a hard time believing that these effects, being immeasurable, justify the removal of an amino acid which has very measurable and profound effects on protein synthesis/protein breakdown.

Regarding leucine's ability to decrease insulin sensitivity, we must once again measure the positive against the negative. Many things we put in our body have the potential to reduce insulin sensitivity--many to a much greater degree than leucine--yet their benefical effects on muscle growth far outweigh their negative effects on muscle growth via decreased insulin sensitivity.

For example, exogenous insulin (as well as endogenous insulin, for that matter) have a negative effect on insulin sensitivity. Even a single injection of insulin we administer will alter insulin sensitivity for the worse. However, this does not mean we eliminate all insulin from our body--it simply means that we must strike the right balance between insulin sensitivity and insulin levels. Many factors have a much greater effect on insulin sensitivity than leucine, such as our daily carbohydrate intake, activity level, etc, yet this doesn't mean we stop eating carbs, do cardio 20X a day, or in the case of insulin users, stop administering insulin.

To further elaborate, the recovery & growth benefits of pre-workout insulin far outweigh any negative effects on growth that might result from the subsequent decrease in insulin sensitivity. Therefore, we keep using pre-worokout insulin despite its ability to reduce sensitivity. The benefits simply outweigh the negatives, at least in terms of muscle growth. In the same way, a high-carb diet will reduce insulin sensitivity, but it also results in far more growth than a low-varb diet. Therefore, we follow higher carb diets when growth is the priority, despite their ability to negatively impact insulin sensitivity.

The main reason leucine decreases insulin sensitivity is because leucine itself is insulinogenic--meaning it increases insulin levels--and anytime we increase insulin levels, insulin sensitivity decrease, assuming all other variables remain the same.

I am not discounting the points brought up by M. Rudolph, but to me, it seems like he is reaching to come up with reasons why AML's pre-workout product is better because it doesn't contain leucine. To me, it is like trying to convince someone who is ignorant of the growth benefits of AAS that AAS aren't benefical for muscle growth because they supress natural testosterone production. Obviously, the growth potential of exo. AAS far exceed the growth potential of natural testosterone production, but when speaking to someone who isn't aware of all the factors involved, it could be easy to convince them otherwise. While this analogy is a bit extreme, the point remains.

More so, the small decrease in insulin sensitivity that occurs with leucine administratin can eaisly be reversed through supplementation, or altering any number of other variabales. Should we lose out on the known, substantial growth benefits of leucine just to avoid the small and easily reversible effect that leucine consumption has on on insulin sensitivity?

Or, should we lose out on leucine's benefits just because it may have minor, probably immeasurable negative effects on exercise performance? To me, that is like saying BB'rs shouldn't use tren because it may decrease our endurance and therefore impair our ability to extract maximum benefit from our training. We all know that tren can have far more of an effect on exercise performance than leucine, yet we also realize that the benefits of Tren far outweigh its negative effect on exercise performance. To me, it seems like the author is using this same logic to justify removing leucine from our pre-workout regimen.

Still, in order to make a proper determination, we need to be able to accurately weigh the positive effects of leucine supplementation on muscle growth against its potential negatuve effects on growth via decreased exercise performance and decreaed insulin sensitivity. Based on the information provided in the article, I see no evidence to back up the author's conclusion. Rather, it seems to be more of an endorsement for AML's pre-workout.

 

[dougisbig]

Interesting article, Mike. Thanks for posting.

On the subject of leucine, how long does protein synthesis remain increased after taking a bolus dose? I'm trying to determine the most efficient way to supplement whole food meals on non-training days. Example: someone has 4 whole food meals 3-3.5 hours apart. Is it necessary to supplement every meal in order to maximize protein synthesis or can it be used less often, say, ever other meal in this scenario?

 

[JBEXT81]

How many of y'all actually take this pre-workout?

I do, and workouts are better (for me that is)

 

[Mike Arnold]

How many of y'all actually take this pre-workout?

I do, and workouts are better (for me that is)

I think it is one of the better pre-workout products and have no problem at all with anyone using it. Rather, the point of my post was to question the implication that this product is better simply because it doesn't contain leucine--an assertion I don't buy into.

It seems to me that the article was written as a way to differentiate AML's pre-workout product from the competition, as most of the better pre-workout products today contain leucine. If the author can get people to believe that leucine containing pre-workout products are counterproductive to muscle growth, there is a greater chance they will buy this product.

I also think its also relevant to mention that pre-workout leucine consumption is actually intra-workout supplementation, as the aminos we consume immediately before a training session will not be delivered to muscle tissue until during the workout.

Lastly, M. Rudolph is employed by the owner of AML, Steve Blechman, as a writer-collumnist for MD magazine. So, while Rudoplh may not make any money on the sale of AML products, he is certainly on Steve's payroll. I am not implying that M. Rudoplh would intentionally disemminate dishonest information, but there are ways of using the truth in order to convey a point which may not be wholly truthful. Of course, M. Rudoplh may fully believe that the negative effects of leucine on exercise performance and insulin sensitivity do outweigh the benefits associated with pre-workout leucine consumption. I just don't think they do, especially when leucine's negative effect on insulin sensitivity is so easily mitigated and any decrease in workout performance is so minor that it is unrecognizable to the individual.

 

[Knight9]

49.95 for 20 servings!?

I am impressed with the contents. 400mg caffeine is excessive, but citrulline malate, creatine, beet root, betaine, beta alanine are all great and have the OPTIMAL amounts involved. That's a first - it seems!

**broken link removed**

 

[Mike Arnold]

49.95 for 20 servings!?

I am impressed with the contents. 400mg caffeine is excessive, but citrulline malate, creatine, beet root, betaine, beta alanine are all great and have the OPTIMAL amounts involved. That's a first - it seems!

**broken link removed**

Yep--it's pretty good stuff. In fact, the entire AML line is pretty progressive. They have made solid attempts to differnetiate themselves from the competition by using new and effective ingredients in some of their products. Their fat burner is a good example.

Like you mentioned, they also use clinically effective doses for every single ingredient in their products.

 

[Knight9]

I'd like to see Agmatine and or Hydromax in that or a similar formula. Can't think of another intriguing compound worth adding..

 

[warlock]

Mike,

If money was not an issue, how would you use leucine for best results? Would you use 5gr pre, intra and post-workout, then 5 additional gr with meals??

 

[Mike Arnold]

Mike,

If money was not an issue, how would you use leucine for best results? Would you use 5gr pre, intra and post-workout, then 5 additional gr with meals??

It would depend on what other protein I was consuming, as well as their qauntities.

I think adding 2-3 grams to each meal, especially meat-based meals, but no more often than every 4 or so hours, is a good idea for just about everyone.

Remember, the protein we consume does contain leucine--often quite a bit. While the digestion rate of many protein sources may not be ideal for optimizing leucine induced protein synthesis, we still need to consider the leucine content of each protein source when deciding how much additional leucine to add to each meal.

Taking too much leucine too often can actually hinder protein synthesis. The body cannot continually be in a state of protein syntesis...and if you try to make that happen by taking large amounts of leucine continuously, it will just backfire and cause protein synthesis to downregulate.

For this reason, I recommend at least 4 hour intervals between each dose of leucine, with a maximum of 4-5 daily doses.

There is no need to consume 5 grams of leucine before training, during training, and after training. That is overkill, as you would be consuming 15 grams of leucine over just a couple hours--way too much. If you consume 5 grams of leucine during the pre or intra-workout window, there is no reason to consume additional leucine for at least another 4 hours. This does not apply to leucine containing foods, such as meat or protein powders, but to supplemental leucine.

 

[warlock]

It would depend on what other protein I was consuming, as well as their qauntities.

I think adding 2-3 grams to each meal, especially meat-based meals, but no more often than every 4 or so hours, is a good idea for just about everyone.

Remember, the protein we consume does contain leucine--often quite a bit. While the digestion rate of many protein sources may not be ideal for optimizing leucine induced protein synthesis, we still need to consider the leucine content of each protein source when deciding how much additional leucine to add to each meal.

Taking too much leucine too often can actually hinder protein synthesis. The body cannot continually be in a state of protein syntesis...and if you try to make that happen by taking large amounts of leucine continuously, it will just backfire and cause protein synthesis to downregulate.

For this reason, I recommend at least 4 hour intervals between each dose of leucine, with a maximum of 4-5 daily doses.

There is no need to consume 5 grams of leucine before training, during training, and after training. That is overkill, as you would be consuming 15 grams of leucine over just a couple hours--way too much. If you consume 5 grams of leucine during the pre or intra-workout window, there is no reason to consume additional leucine for at least another 4 hours. This does not apply to leucine containing foods, such as meat or protein powders, but to supplemental leucine.

First off, thank you Mike for always be so willing to educate us with your knowledge. I always learn a lot from you and I highly appreciate your time.

From reading this, we can state that, generally speaking, one can benefit from using 2-3 gr of leucine every 4 hours or so for up to 4-5 doses daily while keeping 5 gr of it either pre or intra-workout. You mentioned it would be best to add the 2-3 gr to your meals. My question is.... if four hours or so have passed by but it is not time for you to eat, could you use the leucine in between your meals or 30-45 minutes prior to your meals or you are better off waiting longer and add it specifically to your meal?

 

[Pbfanatic321]

I was working with a coach who is pretty reputable (won't say his name, however he is an IFBB pro) and he has me consuming 5 grams of luecine between meals 2 and 3 and between meals 5 and 6. Along with that leucine, 5 grams of arginine as well. Also had it in my intra-workout shake. Just thought I would share this, to add on to Mike's consuming 2-3g leucine every 4 hours.

Thanks for the post Mike.

 

[JBEXT81]

Found this from a Layne Norton article.... thought I'd pass along

Layne Norton PhD on protein: how much and how often? - Spot Me Bro

 

[Knight9]

First off, thank you Mike for always be so willing to educate us with your knowledge. I always learn a lot from you and I highly appreciate your time.

From reading this, we can state that, generally speaking, one can benefit from using 2-3 gr of leucine every 4 hours or so for up to 4-5 doses daily while keeping 5 gr of it either pre or intra-workout. You mentioned it would be best to add the 2-3 gr to your meals. My question is.... if four hours or so have passed by but it is not time for you to eat, could you use the leucine in between your meals or 30-45 minutes prior to your meals or you are better off waiting longer and add it specifically to your meal?

I was working with a coach who is pretty reputable (won't say his name, however he is an IFBB pro) and he has me consuming 5 grams of luecine between meals 2 and 3 and between meals 5 and 6. Along with that leucine, 5 grams of arginine as well. Also had it in my intra-workout shake. Just thought I would share this, to add on to Mike's consuming 2-3g leucine every 4 hours.

Thanks for the post Mike.

I hope you bros understand that Mike is suggesting adding 2-3g to meals to add to the leucine that will already be present in the chicken/meat/fish meals!

 

[homonunculus]

Can Leucine Consumption Before Exercise Hinder Performance?​

By Michael J. Rudolph, Ph.D​

<SNIP>

Well, I'll just note that he seems to be simply theorizing and speculating when there are relevant direct exercises studies (in humans) that exist, e.g., with BCAA's:

Administration of branched-chain amino acids during sustained exercise ? effects on performance and on plasma concentration of some amino acids - Springer

"The results showed that both mental and physical performance was improved by an intake of BCAA during exercise. In addition, the effects of exercise on the plasma concentration of the aromatic amino acids were altered when a BCAA supplement was given during the marathon."


Effects of dietary leucine supplementation on exercise performance - Springer

"Leucine supplementation had no effect on the plasma tryptophan to BCAA ratio, HR or anthropometric variables. Six weeks’ dietary leucine supplementation significantly improved endurance performance and upper body power in outrigger canoeists without significant change in the plasma ratio of tryptophan to BCAA."

-S

 

[superbigd]

Mike arnold - what is your opinion on carnivor beef protein isolate vs true nutrition beef protein isolate vs Olympian labs beef protein isolate. I am a guy that is sensitive to whey and milk proteins and read a post by you suggesting beef protein. Also what's your opinion of Gemma pea?

Where are you doing a majority of your posting these days. I use to follow you on Blackstone labs. Thanks man hope all is well

 

[Mike Arnold]

Well, I'll just note that he seems to be simply theorizing and speculating when there are relevant direct exercises studies (in humans) that exist, e.g., with BCAA's:

Administration of branched-chain amino acids during sustained exercise ? effects on performance and on plasma concentration of some amino acids - Springer

"The results showed that both mental and physical performance was improved by an intake of BCAA during exercise. In addition, the effects of exercise on the plasma concentration of the aromatic amino acids were altered when a BCAA supplement was given during the marathon."


Effects of dietary leucine supplementation on exercise performance - Springer

"Leucine supplementation had no effect on the plasma tryptophan to BCAA ratio, HR or anthropometric variables. Six weeks’ dietary leucine supplementation significantly improved endurance performance and upper body power in outrigger canoeists without significant change in the plasma ratio of tryptophan to BCAA."

-S

See bold above: Exactly. The article's agenda is to lead people to AML's new pre-workout product.