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Essential Amino Acids — What They Are and Why You Need Them

EAAs help with muscle-protein synthesis and Kion Aminos can help you incorporate them into your routine.

Many products are vying for their spot in your supplement stack. From vitamins and pre-workouts to digestive or joint health supplements, it can be challenging to know how to simplify or understand what is necessary for your goals. Essential amino acids (EAAs) are likely among those items in your stack or at least are a consideration for inclusion, as they are considered dietarily essential — as their name implies — but not naturally produced by humans. (1)

There are many benefits of EAAs, primarily their positive influence on improving muscle protein synthesis (MPS) — the body’s adaptive response to exercise. Per Nutrition & Metabolism, “regardless of age or gender, resistance training or provision of adequate amounts of dietary protein (PRO) or essential amino acids (EAA) can increase MPS in healthy adults.” (2)(3)(4)

There are nine essential amino acids, including phenylalanine, valine, tryptophan, threonine, isoleucine, methionine, histidine, leucine, and lysine.” (5) Let’s break down what each of the EAAs do and why a product like Kion Aminos Powder, which provides doses of all nine EAAs across their four available flavors — Mango, Cool Lime, Watermelon, and Mixed Berry — is worth potential inclusion to your supplement stack.

Kion Aminos Powder
Kion Aminos Powder
Kion Aminos Powder

This EAA powder is available in four flavors, each including doses of all nine essential amino acids: phenylalanine, valine, tryptophan, threonine, isoleucine, methionine, histidine, leucine, and lysine. Each tub comes with 30 servings.

Editor’s Note: The content on BarBend is meant to be informative in nature, but it should not be taken as medical advice. When starting a new training regimen and/or diet, it is always a good idea to consult with a trusted medical professional. We are not a medical resource. The opinions and articles on this site are not intended for use as diagnosis, prevention, and/or treatment of health problems. They are not substitutes for consulting a qualified medical professional.

Benefits of EAAs

While more evidence is needed, many studies suggest EAAs — leucine in particular — support MPS. This is even more potent in older athletes as “EAA supplementation maintained over time can improve lean body mass.” Therefore, getting adequate protein in our diets (especially if we are active) is important because of the EAAs found in protein, which function as the building blocks of muscle. (6)(7)(8)

As a pre-workout, Kion touts their Aminos Powder as a means to energy without stimulants, improves stamina (and therefore performance) during training, and protects lean muscle during fasted cardio.

As a post-workout, the EAAs in Kion Aminos Powder (also available in capsule form) could help maintain lean muscle and reduce necessary recovery time. Kion recommends taking their Aminos Powder every three hours if fasting to prevent muscle loss as lean soft tissue has shown to decrease more than fat during extended fasting periods, though both decrease significantly. (9)

Here are some of the many processes amino acids support: (10)(11)(12)(13)(14)(15)(16)(17)

  • Healthy blood sugar levels 
  • Growth hormone production
  • Connective tissue health
  • Cardiovascular health
  • Liver function
  • Mood, norepinephrine, and dopamine synthesis
  • Nervous system function
  • Adrenaline and noradrenaline release
  • Fat metabolism
  • Immune function
  • Serotonin production and sleep regulation
  • Immune function
  • Hemoglobin production
  • Blood cell manufacture
  • Nerve cell protection 
  • Gastric secretion
  • Sexual functions

There are three processes supported by amino acids: energy, muscle, and recovery. Check out a breakdown of each below:


Aminos can boost energy, without caffeine or other stimulants, in three ways. First, by supporting mitochondrial production and effectiveness for improved energy production and athletic performance. Second, by reducing muscle fatigue during endurance and strength-related activities. And finally, by counteracting mental fatigue by replenishing the thrice-fold increased rate of leucine oxidation during exercise that otherwise allows increased amounts of tryptophan to cross the blood-brain barrier and induce serotonergic effects.

Kion Aminos

The EAA lysine, in particular, is involved in energy production through glycogenic and ketogenic formation of glucose, glycogen, and lipids. It can also be metabolized to acetyl CoA, which is involved in carbohydrate metabolism and energy production. Lysine is also a precursor for L-carnitine, an amino acid involved in transporting fatty acids into the mitochondria for energy production. (18)

Muscle and Strength

Taking aminos can support the creation of new, stronger, healthier muscles faster than protein alone. Due to muscle proteins being in a constant state of turnover, building (even maintaining) muscle requires MPS to exceed muscle protein breakdown (MPB). EAAs cause a spike in the amino acid profile of blood faster than protein, and because EAAs reduce MPB while simultaneously increasing MPS, they are crucial for anyone looking to build muscle.

The amino acid leucine plays a particularly important role in MPS. In one 2020 study in the Journal of Sports Medicine and Physical Fitness, 30 male college athletes were randomly assigned to receive either whey protein, leucine, or a placebo. The subjects then underwent resistance training for eight weeks. Strength, bench press, squat, shoulder press, maximum pull-ups, and body composition were assessed. The leucine group achieved significantly greater gains in fat-free mass and muscle mass and significant decreases in fat mass compared to whey and placebo groups. (19)

A 2002 study in the American Journal of Physiology, Endocrinology, and Metabolism found that taking EAAs after resistance training led to the stimulation of MPS after exercise. Aminos can supply muscles with energy during a workout, which can help maintain strength. For example, another study one study published in 2018 in Frontiers in Physiology found that the ingestion of EAAs before a weightlifting workout led to the research group having more strength in their biceps than the control group who were given a placebo. (20)(21)


Aminos can enhance athletic recovery by reducing soreness and improving readiness for subsequent exercise by reducing MPB and damage. How well one recovers can be equally as important as how hard one trains. In particular, valine, leucine, and isoleucine have been shown to have positive benefits for exercise recovery, including promoting glucose uptake by muscles. (22)

A meta-analysis in the International Journal for Vitamin and Nutrition Research examining the effect of BCAA supplementation on delayed onset muscle soreness (DOMS) examined 93 participants in five studies. The results indicated that DOMS decreased following BCAA supplementation when compared to placebo. (23)

Kion Aminos

Another meta-analysis in Nutrition examined eight randomized clinical trials on the effect of valine, leucine, and isoleucine supplementation on exercise-induced muscle damage and recovery. It was shown that these three EAAs are better than passive recovery or rest after various forms of exhaustive and damaging exercise. Yet another 2017 research review in Nutrients found that there was evidence for the EAAs leucine, isoleucine, and valine, in particular, being effective for recovery and minimizing muscle damage caused by exercise. (24)(25)

Below is a brief breakdown of each of the nine EAAs and their benefits for a routine gymgoer, including those more related to improved metabolism, athletic performance, and longevity.

Note: doses mentioned for each EAA below can vary depending on one’s diet and should not be taken as medical advice.


According to the National Center for Biotechnology Information, phenylalanine “plays a key role in the biosynthesis of other amino acids.” It is used in biosynthesis — the production of molecules in cells —  of dopamine and norepinephrine transmitters after being converted to the precursor amino acid tyrosine. Tyrosine potentially helps combat “decrements in cognitive performance.”(13X)(26)

There is not a set daily phenylalanine requirement for any age group yet. Still, there are suggested estimates of approximately 38 milligrams per kilogram of body weight per day (minus one) — meaning that a 180-pound adult could consume a little over three grams. Kion Aminos Powder provides 350 milligrams of phenylalanine per serving, right in that range. (27)


Valine helps determine the three-dimensional structure of globular proteins’ interior and “maintains mental vigor, muscle coordination, and emotional calm. As a stimulant, it “promotes muscle growth and tissue repair.” (28)


Tryptophan is a precursor to serotonin — a neurotransmitter involved in regulating behavior, mood, and memory. As such, tryptophan can help suppress feelings of depression and anxiety. (29)(30)

While further studies are needed for improved accuracy, a 2021 systemic review of tryptophan in the Journal of Dietary Supplements suggested a recommended daily dose in the range of 0.14 to three grams of tryptophan in addition to meals. Kino Aminos Powders provides 3.5 grams of tryptophan per serving.


Threonine can be used to potentially help alleviate mild depression and anxiety but primarily functions for “fat metabolism and preventing fat buildup in the liver.” While specific dosing for threonine is not set in stone, 15 milligrams per kilogram of body weight minus one has shown to be “sufficient to achieve mean amino acid balance.” (14X)(31)


Isoleucine “can improve the immune system.” Additionally, it can assist in wound healing, stimulate immune function, promote the secretion of several hormones, and is necessary for blood sugar and energy regulation. (32)(16X)


Methionine is required for tissue repair and “improves the tone and pliability of skin, hair, and strengthens nails.” Additionally, it is essential for the absorption of selenium and zinc. The former helps regulate the immune and reproductive systems, and the latter is critical for proper metabolism function. (12X)(33)(34)


Histidine performs essential…”anti-oxidant and anti-secretory functions.” It also modulates inflammatory response and gastric acid regulation. Other potential benefits of histidine are reduced appetite, anxiety, and stress responses, as well as improved sleep. (35)

However, due to the limited research available, the upper limit of histidine dosage isn’t clear, though doses greater than 24 grams per day have shown some adverse cognitive effects. (36)


Leucine stimulates MPS and energy metabolism while “inhibiting protein degradation.” Furthermore, leucine intake post-exercise can support muscle repair and recovery. (37)(38)(39)


Lysine’s primary role is in protein synthesis, wound healing, and inducing angiogenic responses — developing new blood cells. A 2019 systemic review in Amino Acids determined that lysine 16.8 to 17.5 grams per day had adverse effects on digestion. Kino Aminos Powders’ lysine content is in the much more conservative range of 850 milligrams. (40)(41)(42)

Kion Aminos Powder
Kion Aminos Powder
Kion Aminos Powder

This EAA powder is available in four flavors, each including doses of all nine essential amino acids: phenylalanine, valine, tryptophan, threonine, isoleucine, methionine, histidine, leucine, and lysine. Each tub comes with 30 servings.

Get the Essentials

Now that you have a sense of the role of each of the nine EAAs, and that they are dietary necessities since the human body does not naturally produce them — an EAA supplement powder may be worth considering if your diet is deficient in any of them. Of course, it is always best to consult your physician before adjusting your diet with supplements. Though more research is needed for confident dosing of each EAA, the current science would likely support the dosing provided by Kion Aminos Powder.


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Featured image courtesy of Kion.