BCAAs vs. EAAs - Which Are Better for Building Muscle?

BCAAs vs. EAAs - Which Are Better for Building Muscle?

“BCAAs are useless.”

“BCAAs are worthless.”

“You’re wasting money on BCAAs.”

Related - Shop the Top 10 BCAA Supplements

Statements along these lines have been uttered countless times over the past year as some research has come out questioning the effectiveness or “necessity” of branched-chain amino acid supplements (BCAAs).

In the aftermath of this published literature, an uprising against BCAA supplements has taken place, with the one-time “staple” of bodybuilders coming under assault from all directions, including such outrageous claims that BCAAs aren’t anabolic, and that they do nothing but “fuel cancer.” [1]

Co-comitant with this bashing of all things BCAA is a rapid increase in the number of essential amino acid supplements (EAAs) flooding the market, touting their superiority as the true king of intra-workout supplementation.

In all of this back and forth, there’s more confusion than ever for the uninformed consumer regarding which amino acid supplement they should buy, if any.

We’re here to help provide some much-needed clarity to the situation.

Let’s start at the top by answering a simple question…

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What are BCAAs?

BCAA stands for branched-chain amino acid. Your body uses 20-22 amino acids (the exact number is up for debate) to construct protein. Within this group of amino acids, you have essential amino acids (EAAs) and non-essential amino acids.

The essential amino acids are a group of nine amino acids that the body cannot synthesize on its own and must obtain them through the diet. The nonessential amino acids are ones the body can self-generate from a combination of the essential amino acids, carbohydrates, and fats, hence their being dubbed “nonessential.”

BCAAs are a special “subcategory” of the essential amino acids that obtained their name “branched-chain” due to their unique branch-like structure. The three branched-chain amino acids are:

  • Leucine
  • Isoleucine
  • Valine

The nine essential amino acids are:

  • Leucine (BCAA)
  • Isoleucine (BCAA)
  • Valine (BCAA)
  • Histidine
  • Lysine
  • Methionine
  • Phenylalanine
  • Threonine
  • Tryptophan

Why are EAAS Important?

OK, now that you’ve got a handle on the different kinds of amino acids, we can start getting to the more pressing and important points of this article, such as whether or not BCAA are “useless.”

First up, let’s discuss why essential amino acids are important.

Well, muscles are made of protein, and protein is made up of amino acids. Your body synthesizes new proteins (and subsequently muscle) from these amino acids. However, muscle protein synthesis only occurs if all nine of the essential amino acids are present in sufficient quantities. That means that if just one of the essential nine amino acids is missing, protein synthesis grinds to a halt, and so do your gains.

Now, in order to for protein synthesis to even begin, your body needs to flip the “on” switch to start the protein assembly factory. The great thing about the human body is that there are multiple ways to flip this “on switch.”

The most powerful of activator or “switch flipper” of protein synthesis is the branched-chain amino acid leucine, the “king” of amino acids. [5] Leucine activates the mechanistic target of rapamycin (mTOR) pathway, which is the “switch” that turns on muscle protein synthesis.

Other means for activating mTOR and ratcheting up protein synthesis include resistance exercise or consuming any type of mixed meal. [2] Consuming food, especially carbohydrates, whey protein, or individual amino acids such as leucine, triggers your body to release insulin, which in and of itself activates mTOR and gets your body’s protein-producing factory cranking full steam ahead. [3]

So, to recap, your body needs all nine of the essential amino acids present to build proteins, and the process of protein synthesis gets activated by one of several different triggers, leucine (one of the BCAA) being quite possibly the most potent potentiator of the protein production process.

Got it?


Up next….

More About Leucine and the BCAA

Once researchers discovered that leucine was the real “anabolic trigger” that ignites protein synthesis, more and more studies were conducted to identify how much of it was needed to actually “flip the switch” on mTOR, and from these studies came some other very interesting finds about leucine and the rest of its BCAA brethren.

For starters, researchers figured out that the “magic” amount of leucine to activate mTOR on its own and subsequently stimulate protein synthesis is between 2.5 - 3 grams. However, this amount can be lowered to around 1.8 grams of leucine is congested with all of the other essential amino acids. [6]

Secondly, unlike the vast majority of amino acids which are oxidized in your liver, the three branched-chain amino acids are oxidized directly in skeletal muscle. This important characteristic of the three BCAA brings to light two other unique benefits they can offer: [4][7]<.sup>

  • Energy production, thus sparing your glycogen stores for later in the workout
  • Anti-catabolic actions, preventing muscle breakdown if training fasted

A few other key points worth noting about the two “lesser” BCAA in valine and isoleucine are in regards to their ability to prolong exercise performance. More specifically, valine and the essential amino acid tryptophan compete for uptake in the brain. [8]

In case you weren’t aware, tryptophan is the amino acid precursor used to produce serotonin, a neurotransmitter/hormone that signals to your body that it’s becoming fatigued during intense exercise, subsequently resulting in you ending a set early and missing out on some “untapped” gains.

However, by supplementing with BCAA, valine will essentially “clog up” the receptor, inhibiting production of serotonin and thereby combating mental fatigue.

Isoleucine is another mild stimulator of mTOR, but nowhere near as potent as its big brother, leucine. However, where isoleucine does stand out is in regards to its ability to enhance glucose uptake and utilization by skeletal muscle, without significantly elevating plasma insulin levels. [9][10]

Improving the rate at which your muscles take up glucose and use it translates to better performance and stamina during your workouts. Remember, during high-intensity exercises, such as weightlifting or sprinting, glucose is the preferred fuel for the body, regardless of what the keto proponents are spewing these days.

Now that the basics (and then some) of the branched-chain amino acids have been addressed, we can begin to provide some clarity to the back and forth that’s transpired regarding BCAAs vs EAA.

So, let’s start with the most common statement recently - “BCAA are useless.”

Are BCAAs useless?

We’ll come right out of the gate and say a definite no; the BCAAs in and of themselves are not “useless.”

Remember, protein synthesis is an “all or nothing” proposition. Your body either has enough quantity of all the essential amino acids, including the three BCAA, to sustain protein synthesis or it doesn’t. If any of the amino acids are lacking, protein synthesis grinds to a halt, which means muscle growth does too, but we’ll get into that more in a bit.

Additionally, protein synthesis relies on the BCAA to get started, as we’ve discussed when we talked about activating mTOR. Plus, BCAAs account for approximately ? of all muscle protein. [3]

They also serve as nitrogen donors for other amino acids, such as alanine, glutamine, and glycine, and they are frequently used as biomarkers for monitoring diseases such as insulin resistance, type 2 diabetes, cancer, and cardiovascular disease. [11]

So, to say that BCAAs are useless or “unnecessary” is slightly ridiculous.

Now, let’s address some of the hype and claims regarding BCAAs, EAAs, and muscle building.

BCAA, EAA, and Building Muscle

In a muscle cell, there exists a regulatory pathway for protein synthesis that’s stimulated by insulin; however, while it’s stimulated by insulin, it depends on leucine. [12]

Another way of saying that, would be to say that protein synthesis (i.e. muscle building) hinges on how much leucine is available, and since levels of BCAA dramatically decline during exercise, supplementing with them before, during, or after workouts makes a lot of sense. [7]

However, as awesome as BCAAs seem, where people (i.e. supplement companies) get into trouble is overselling the idea that BCAAs are all that are needed for muscle growth or that using them around training will lead to life-altering changes in muscle growth (they won’t by the way...

The truth is that you need all nine essential amino acids to build muscle. The BCAA provide just three pieces of the nine-piece puzzle.

In a sense, you can look at BCAAs starting the engine on protein synthesis and the other six essential amino acids keep it running, which leads to the creation of new protein structure, and ultimately more muscle.

Additionally, it’s important to remember what muscle building really is. Muscle building occurs when protein synthesis outpaces protein breakdown for a prolonged amount of time. Essentially, to build muscle and grow, your body must be making more protein than it breaks down on a regular basis.

The BCAAs support this in two ways. First, by “flipping the switch” on muscle building (via mTOR activation), and by limiting muscle protein breakdown. Remember, growth occurs when there is more muscle synthesis than breakdown, so by lowering or reducing the amount of breakdown that occurs in muscle, the BCAAs indirectly enhance the overall balance of protein synthesis in the body.

Now, let’s get to the most recent research regarding that’s started the whole BCAAs vs EAAs debate.

Recent Amino Acid Research

The real catalyst for this EAA vs BCAA debacle essentially began after a review was published by Robert Wolfe, a consultant for TriVita Wellness, a multilevel marketing company that sells a product called MyoHealth, which uses a proprietary blend of essential amino acids concocted by Wolfe and another researcher.

So, if you step back and think about it, it makes sense for him to promote the idea that EAA are clearly superior to BCAA. We’re not saying that’s the driving force behind his research, but it’s something that should be considered when discussing his work.

In his amino acid review paper, titled Branched-chain amino acids and muscle protein synthesis in humans: myth or reality?, Wolfe & company concludes that:

“BCAA supplements alone do not promote muscle anabolism.” [13]

Supplement users (and YouTube “experts”) who glance through abstracts and think they’ve got a handle on the situation have interpreted this as meaning “BCAA are useless.” But, when you look beyond study abstracts and really dive into the full studies published on BCAAs and EAAs, you’ll see that statements such as “BCAAs are useless” is a gross oversimplification of the data.

Additional research regarding the whole BCAA vs EAA debate has stated:

“BCAAs stimulated a 22% greater response of myofibrillar-MPS following resistance exercise compared with a placebo... The magnitude of this increased response of myofibrillar-MPS was ~50% less than the previously reported myofibrillar-MPS response to a dose of whey protein containing similar amounts of BCAA."

"Results demonstrate that BCAAs exhibit the capacity to stimulate myofibrillar-MPS, however, a full complement of EAA could be necessary to stimulate a maximal response of myofibrillar-MPS following resistance exercise…"

"Our data support the notion that BCAA ingestion alone does not maximally stimulate myofibrillar-MPS following exercise despite stimulation of translation initiation pathways. The lack of sufficient EAA appears to limit the response of myofibrillar-MPS following exercise…ingestion of BCAAs alone may not be the optimal nutritional regimen to stimulate a maximal MPS response to resistance exercise training.” [14]

“In summary, oral supplementation with BCAA following resistance exercise stimulates mTORC1 signaling more potently than ingestion of leucine alone, but not as effectively as EAA.” [17]

What can be gleaned from these studies isn’t that BCAAs are a waste of money, or useless, quite the opposite in fact. What this research is telling us, is that the BCAA do support anabolism and promote an increase in muscle protein synthesis.

BUT, the upregulation in protein synthesis is not greater than that of whole protein (i.e. whey protein) or an essential amino acid formula.

In other words, if you’re faced with training fasted or using BCAAs, use BCAAs. They’ll improve the anabolic response to exercise and recovery, as well as reduce fatigue, pain sensation, muscle damage, and perceived effort during training. [18]

However, if you’re really focused on building as much muscle as possible and really maximizing your body’s anabolic response, a whey protein shake or EAA supplement consume pre-workout might be the superior option.


Remember though, these studies are all relatively short term. They last at most 8-12 weeks, which isn’t long enough to see how your “lifetime gains” are affected by using BCAAs or EAAs. All of these individual studies and reviews simply provide additional data points in our ongoing discovery and understanding of human metabolism and muscle growth.

Are you missing out on “epic gains” if you’re not using EAAs during training and only using BCAAs?

No, not in the least.

If anything, BCAAs help protect your muscles against exercise-induced breakdown, and in essence “hold you over” until your post workout meal, which contains hopefully a complete protein of some kind, such as whey protein. Furthermore, if you’re consuming adequate protein daily (i.e. 0.8-1g per pound of bodyweight) any additional amino acid supplements on top of that, regardless of EAA or BCAA, is probably a moot point, unless you’re training fasted, as your body can only use so much protein each day. The rest is converted into glucose.

The more recent studies regarding EAAs and BCAAs have been used as cannon fodder by those seeking to push more supplements in the industry and increase notoriety, instead of what they should be used for - furthering our understanding of human protein synthesis and how to further enhance gains.

To flippantly state that BCAAs, EAAs, or any other amino acid supplements are a “waste” or “useless” is missing the forest through the trees and highlights a gross negligence of the available data.

1) "BCAA Are CANCER FUEL!!!" YouTube, 6 Mar. 2018, www.youtube.com/watch?v=QWHSaZlPw0w.
2) Song Z, Moore DR, Hodson N, et al. Resistance exercise initiates mechanistic target of rapamycin (mTOR) translocation and protein complex co-localisation in human skeletal muscle. Scientific Reports. 2017;7:5028. doi:10.1038/s41598-017-05483-x.
3) Deldicque L, Theisen D, Francaux M. Regulation of mTOR by amino acids and resistance exercise in skeletal muscle. Eur J Appl Physiol. 2005;94(1-2):1-10. doi:10.1007/s00421-004-1255-6
4) Harper AE, Miller RH, Block KP. Branched-chain amino acid metabolism. Annu Rev Nutr. 1984;4:409-454. doi:10.1146/annurev.nu.04.070184.002205
5) Drummond MJ, Rasmussen BB. Leucine-Enriched Nutrients and the Regulation of mTOR Signalling and Human Skeletal Muscle Protein Synthesis. Current opinion in clinical nutrition and metabolic care. 2008;11(3):222-226. doi:10.1097/MCO.0b013e3282fa17fb.
6) Glynn EL, Fry CS, Drummond MJ, et al. Excess Leucine Intake Enhances Muscle Anabolic Signaling but Not Net Protein Anabolism in Young Men and Women. The Journal of Nutrition. 2010;140(11):1970-1976. doi:10.3945/jn.110.127647.
7) Mero A. Leucine supplementation and intensive training. Sports Med 1999;27:347-358.
8) Gomez-Merino D, Bequet F, Berthelot M, Riverain S, Chennaoui M, Guezennec CY. Evidence that the branched-chain amino acid L-valine prevents exercise-induced release of 5-HT in rat hippocampus. Int J Sports Med. 2001;22(5):317-322. doi:10.1055/s-2001-15645
9) Zhang S, Yang Q, Ren M, et al. Effects of isoleucine on glucose uptake through the enhancement of muscular membrane concentrations of GLUT1 and GLUT4 and intestinal membrane concentrations of Na+/glucose co-transporter 1 (SGLT-1) and GLUT2. Br J Nutr. 2016;116(4):593-602. doi:10.1017/S0007114516002439
10) Doi M, Yamaoka I, Nakayama M, Sugahara K, Yoshizawa F. Hypoglycemic effect of isoleucine involves increased muscle glucose uptake and whole body glucose oxidation and decreased hepatic gluconeogenesis. 2018:1683-1693. doi:10.1152/ajpendo.00609.2006.
11) Nie C, He T, Zhang W, Zhang G, Ma X. Branched Chain Amino Acids: Beyond Nutrition Metabolism. International Journal of Molecular Sciences. 2018;19(4):954. doi:10.3390/ijms19040954.
12) Joshua C. Anthony, Tracy G. Anthony, Scot R. Kimball, Leonard S. Jefferson; Signaling Pathways Involved in Translational Control of Protein Synthesis in Skeletal Muscle by Leucine, The Journal of Nutrition, Volume 131, Issue 3, 1 April 2001, Pages 856S–860S, https://doi.org/10.1093/jn/131.3.856S
13) Wolfe, R. R. (2017). Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? Journal of the International Society of Sports Nutrition, 14(1), 30.
14) Jackman SR, Witard OC, Philp A, Wallis GA, Baar K, Tipton KD. Branched-Chain Amino Acid Ingestion Stimulates Muscle Myofibrillar Protein Synthesis following Resistance Exercise in Humans. Frontiers in Physiology. 2017;8:390. doi:10.3389/fphys.2017.00390.
15) Churchward-Venne T. A., Burd N. A., Mitchell C. J., West D. W., Philp A., Marcotte G. R., et al; Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. J. Physiol. 590, 2751–2765; 2012;
16) Oliver C Witard, Sarah R Jackman, Leigh Breen, Kenneth Smith, Anna Selby, Kevin D Tipton; “Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise”; The American Journal of Clinical Nutrition; Volume 99, Issue 1, Pages 86–95; January 1, 2014;
17) Moberg M, Apró W, Ekblom B, Hall G Van, Holmberg H, Blomstrand E; “Activation of mTORC1 by leucine is potentiated by branched-chain amino acids and even more so by essential amino acids following resistance exercise”; Am J Physiol Cell Physiol; 2018:874-884
18) Salinas-García ME, Martínez-Sanz JM, Urdampilleta A, Mielgo-Ayuso J, Norte Navarro A, Ortiz-Moncada R. [Effects of branched amino acids in endurance sports: a review]. Nutr Hosp. 2014;31(2):577—589. doi:10.3305/nh.2015.31.2.7852
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