You're likely up to speed on branched-chain amino acids (BCAAs), but there's a new sheriff in town: essential amino acids (EAAs). BCAA supplements took over as the de facto intra-workout supplement of choice for many gym-goers at the turn of the 21st century, but now EAAs are imposing their will as the go-to amino acid supplements for building muscle tissue and promoting exercise performance.
So, what are EAAs, exactly? How do they compare to BCAAs? Which is optimal for muscle growth and reducing muscle soreness? This article will take an evidence-based approach to answer all your questions about these popular amino acid supplements and how they impact muscle protein synthesis.
There are 20 protein-creating amino acids that commonly occur in nature. These 20 amino acids are the veritable "building blocks" of proteins. Since muscle protein synthesis is a prerequisite for building muscle tissue, amino acids play a pivotal role in exercise performance and body composition.
Nine of the 20 amino acids necessary for muscle protein synthesis are nutritionally “essential” since the human body cannot make them on its own. Hence, we must consume EAAs in the diet or through supplementation for proper health and wellness.
The nine EAAs include:
Three of the nine EAAs are branched-chain amino acids: leucine, isoleucine, and valine. The BCAAs are called "branched-chain" amino acids due to their characteristic branching carbon chain structure on a molecular level. Basically, BCAA supplements provide a subgroup of EAAs. (We will discuss the difference between the full-spectrum of EAAs and the three BCAAs in just a bit.)
The remaining 11 amino acids that don't fall into the "essential" category are non-essential amino acids (NEAAs).
The 11 NEAAs include:
The body can synthesize NEAAs endogenously (i.e. "on its own") from other molecules, such as glycerol . In other words, your body can create NEAAs that are lacking in the diet. That can't be said for EAAs. Hence, the rate of muscle protein synthesis is limited by EAA availability .
Some of the NEAAs, notably L-alanine, L-glutamine, and L-arginine, are conditionally essential amino acids. This means they are a necessary component of the diet during certain stages of development and under adverse physiological stress, such as long bouts of endurance exercise and high-intensity training.
However, don't misconstrue the above as saying that only the essential amino acids are important. Your body needs NEAAs for vital physiological processes, like creating neurotransmitters, enzymes, and peptide hormones (such as the blood-sugar regulating hormone insulin).
Moreover, muscle protein breakdown will increase if protein intake isn't sufficient. Consequently, lean body mass is wasted for energy purposes (not ideal for most gym-goers and athletes). As such, EAAs and BCAAs are typically prudent for active individuals that don't consume a protein-rich diet. Those that do eat plenty of protein may also stand to benefit from amino acid supplementation (more on why that is below).
Essential amino acids, especially the branched-chain amino acids (BCAAs), aren't always abundant in dietary protein, notably plant-based sources like legumes and wheat. For those on a vegan or plant-based diet, supplementing with EAAs or BCAAs may be wise.
However, you'll want to find EAA/BCAA supplements that provide fermented, vegan-friendly amino acids. If the product label doesn't explicitly state that the amino acids are fermented or vegan, they are in all likelihood made from animal byproducts.
Furthermore, taking an EAA supplement before, during, and/or after exercise can help you build muscle tissue and prevent muscle protein breakdown even if your protein intake is adequate . Since the amino acids in EAA and BCAA supplements are not bonded together like they are in intact protein, they absorb rapidly and increase muscle protein synthesis with minimal digestive assistance .
Thus far, most studies on EAAs have been clinical studies of patients with sarcopenia or cachexia — medical conditions associated with chronic muscle wasting . The findings of these studies consistently demonstrate that modest doses of EAAs stimulate protein synthesis, mitigate muscle protein breakdown, and encourage muscle growth (even in patients at bed rest).
Scientific lingo aside, EAA supplements are burgeoning for a reason. But what about BCAA supplements?
To reiterate from earlier, the branched-chain amino acids (BCAAs) are a subgroup of EAAs that includes leucine, isoleucine, and valine. BCAAs have garnered praise and fanfare over the past decade due to their role as "master regulators" of muscle protein synthesis .
Research corroborates that the proportion of leucine in dietary protein directly affects the rate of muscle protein synthesis . In layman's terms: the more L-leucine there is in a complete protein source, the more efficiently it builds muscle mass.
The catch is that BCAAs still need the help of the other six EAAs to create new muscle proteins. If you're lacking any of the EAAs, the rate of protein synthesis will be held in check. Thus, it's tough to argue that BCAAs are better than EAAs.
Naturally, gym-goers and bodybuilders assume that "more is better" and drinking EAAs around the clock leads to "extra" muscle growth. Alas, that's not how things work. The body appears to have an innate "cap" for muscle protein synthesis in response to protein/EAA ingestion . Once that peak is reached, there is a refractory period where additional amino acids don't impact the rate of protein synthesis.
Therefore, if your goal is to build muscle, it's best to consume several moderate servings of protein/EAAs spread throughout the day (roughly 3 to 5 hours apart). For the average adult, "moderate" translates to about 25-30 grams of complete protein (e.g. whey protein, chicken breast, eggs) or 10 grams of pure EAAs with a 2:1:1 ratio of BCAAs.
Many gym-goers will sip on EAAs or BCAAs as they go through their workout to support exercise performance and mitigate muscle damage. However, if you eat a protein-rich pre-workout meal before you hit the gym, it's advisable to wait and take EAAs/BCAAs immediately post-workout.
Now that you know the differences between EAAs and BCAAs, the next step is finding the right amino acid supplement for your needs. In most cases, EAAs can replace the use of BCAAs, but not vice versa. EAAs, but not BCAAs, stimulate protein synthesis to a high degree even if you haven't eaten for 6+ hours. BCAAs may inhibit muscle protein breakdown during a fast/between meals, but that's about it .
In fact, EAA supplementation can provide the same anabolic response as complete protein sources like whey protein and casein protein. One study found that a bolus of leucine-enriched EAAs after a workout stimulated protein synthesis as effectively as intact whey protein despite each supplement providing the same proportions of essential amino acids .
The outlook for EAAs is promising, and Transparent Labs Intra is leading the way for those who want to maximize their workouts. This formula goes above and beyond by providing a robust dose of vegan EAAs along with citrulline malate, taurine, betaine anhydrous, elevATP®, Astragin™, and electrolytes to support blood flow, hydration, and stamina during exercise. Best of all, it comes in refreshing blue raspberry and strawberry lemonade flavors with absolutely no artificial additives.