Essential Amino Acids:Benefits,Sources, Supplementation

Essential amino acids are the most important amino acids. Amino acids themselves are the building blocks of proteins and proteins are compounds which play the most critical roles in your body. Apart from being protein builders, they are also part of several hormones and neurotransmitters and here too they play part in equally critical roles.

Since amino acids are protein builders, they are concentrated in protein-rich foods such as meat, fish, and soybeans.

Some amino acids are also taken as supplements to boost athletic performance or to improve mood. Leucine is commonly taken by people interested in muscle building.

Amino acids are divided into three classes :-

Essential amino acids

Non essential amino acids

Conditionally essential amino acids

What are essential amino acids ?

Amino acids are organic compounds and are composed mainly of carbon, nitrogen, hydrogen, and oxygen. Our body needs 20 different amino acids for its growth and function. While all the amino acids are of equal importance for our health, only 9 amino acids are classified as essential amino acids.

The essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. The easiest way to to remember them is by the abbreviation V HILL MP TT

The remaining 12 amino acids are classified as non essential amino acids although they are equally important & play equally vital roles in our body. The reason being that our body can itself synthesize nonessential amino acids, it cannot make the essential amino acids, so it becomes obligatory to get them from our diet & hence they are given the important word essential.

The non essential amino acids are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine.

The rich sources of essential amino acids are animal proteins such as meat, eggs, and poultry. Plant foods such as soy products, edamame and tofu, contain all nine essential amino acids. This means they are complete sources of protein and can themselves be defined as complete proteins.

Conditionally essential amino acids

Some nonessential amino acids are classified as conditionally essential amino acids.

These become essential only under certain circumstances, such as during illness, pregnancy, infancy, or trauma.

For example, arginine is otherwise considered nonessential, but your body can’t make it as much as needed when you’re healing from a serious injury or fighting certain serious diseases like cancer.

In situations like these people take arginine supplements to meet the high demanding needs of these situations.

Additionally, amino acids glycine and arginine, are considered conditionally essential during pregnancy because a pregnant woman needs more of these amino acids to support their own health to allow the good growth of the fetus.


Our body cannot make the nine essential amino acids, so you need to get them from your diet. Conditionally essential amino acids are nonessential amino acids that become essential in certain circumstances, such as illness or pregnancy.

Functions of essential amino acids

All the nine essential amino acids perform a number of important jobs in your body:-

  1. Phenylalanine. Our body turns this amino acid into a number of neurotransmitters like tyrosine, dopamine, epinephrine, and norepinephrine. It plays an integral part in the structure and function of proteins and enzymes and also in the production of other amino acids.
  2. Valine. This is a branched chain amino acid along with leucine, isoleucine & valine. Branched chain means it has a chain branching off from one side of its molecular structure. Valine helps to stimulate muscle growth and regeneration and is also involved in energy production.
  3. Threonine. This is a principal part of major structural proteins, such as collagen and elastin, which are important components of our skin and connective tissue. It also plays an important role in fat metabolism and immune function.
  4. Tryptophan. Tryptophan is a precursor to serotonin, which is an important neurotransmitter that regulates our appetite, sleep, and mood.
  5. Methionine. This is a sulphur containing amino acid along with cysteine and plays an important role in metabolism and detoxification. It’s also necessary for tissue growth and the absorption of minerals like zinc and selenium..
  6. Leucine. Leucine is also a branched chain amino acid that is critical for protein synthesis and muscle repair. It also helps to regulate blood sugar levels, stimulates the process of wound healing, and also plays part in the production of growth hormones.
  7. Isoleucine. This is the last of the three branched chain amino acids and is involved in muscle metabolism and is heavily concentrated in muscle tissue. It is also important for immune function, for hemoglobin production, and energy regulation.
  8. Lysine. It plays a major role in protein synthesis, calcium absorption, and the production of hormones and enzymes. It is also important for energy production, immune function, and also for the production of collagen and elastin.
  9. Histidine. Our body uses this amino acid to produce histamine which is a neurotransmitter that is vital to immune response, digestion, sexual function, and wake sleep cycles. It is critical for maintaining the myelin sheath, the protective barrier surrounding the nerve cells.


The nine essential amino acids perform vital roles in our body like tissue growth, energy production, immune function, and nutrient absorption.

Protein and amino acids are more commonly known for their role in muscle development and repair, though they perform a myriad of functions beyond muscle formation. Though protein and amino acid deficiency in general is good enough to give a setback to your health, the essential amino acids deficiency puts a heavy toll on our health affecting all body systems including the nervous, reproductive, immune, and digestive systems.

Health benefits of taking essential amino acids supplements

Although essential amino acids are found in a wide range of foods, taking their concentrated doses in supplemental form has been linked to several health benefits.

May help with mood

Tryptophan is required for the production of serotonin, which is a chemical that acts as a neurotransmitter in our body.

Serotonin is an essential regulator of sleep, behavior & mood.

Low serotonin levels have been found to be linked to depressed mood and sleep disturbances, several clinical studies have shown that taking tryptophan supplements may help to reduce symptoms of depression and may give a boost to mood.

A review that included 11 high quality studies found that taking 0.14–3 grams of supplemental tryptophan per day could help to decrease anxiety and to give positive mood in healthy people.

May improve exercise performance and recovery

Many people take valine, leucine, and isoleucine, the three essential branched chain amino acids, to remove fatigue, improve athletic performance, and stimulate muscle recovery after exercise.

In a 2017 study, a small group of resistance-trained athletes took branched chain amino acids(BCAAs) at a dose of 0.039 grams per pound (0.087 grams per kg) of body weight, with a 2:1:1 ratio of leucine, isoleucine, and valine.

It was noted that the group who took BCAAs showed improved performance and muscle recovery and decreased muscle soreness compared to those who took a placebo.

Similarly in another eight studies, it was found that taking BCAAs was superior to rest for promoting muscle recovery and reducing soreness after exhaustive exercise.

Further nod was given by another review that included nine studies and which found that taking BCAAs highly helped to reduce muscle damage and soreness after resistance exercise in active men.

Furthermore, taking BCAAs has also been shown to reduce the rating of perceived exertion, which is how intensely a person feels they are working during exercise — in people performing high intensity exercise.

May be helpful for wound healing and surgery

For long time, doctors have been recommending a good protein diet for people who are healing after surgery. Amino acid supplements prove really helpful for people who are healing after surgery.

A study in 243 people with pelvis or long bone fractures found that those who took conditionally essential amino acids for 15 days after surgery had lower rates of death and medical complications than those who received just standard nutrition.

Another review of 20 studies which was looking at the effects of taking BCAAs in people with cancer undergoing surgery found that taking BCAAs around the time of surgery had reduced postoperative complications from infections and fluid accumulation in the abdomen.

The branched chain amino acid supplementation is further proved positive by a study which proved that taking essential amino acid supplements may help to reduce loss of muscle volume in older adults recovering from knee replacement surgery and also the loss of muscle volume in general.


Taking certain essential amino acids in supplement form may help to improve mood, support exercise performance, and help improve recovery after surgery.

Recommended daily intake of essential amino acids

The essential amino acids intake must be sufficient to meet daily body needs as they cannot be synthesized in the body as already mentioned.

There are many foods which are rich in essential amino acids which makes it easy to meet their daily needs.

Following are daily required intakes for all the nine essential amino acids, according to the WHO(World Health Organization). These values are for adults and for per 2.2 pounds (1 kg) of body weight :

  • Isoleucine: 20 mg
  • Leucine: 39 mg
  • Lysine: 30 mg
  • Methionine: 10.4 mg
  • Phenylalanine in combination with nonessential amino acid tyrosine: 25 mg
  • Threonine: 15 mg
  • Tryptophan: 4 mg
  • Valine: 26 mg
  • Histidine: 10 mg

To find out how much of each amino acid you should consume per day, you can multiply the numbers given above by your body weight in kilograms. For example, a person who weighs 60 kg(132 pounds) should consume 1,200 mg(1.2 grams) of isoleucine per day.

Meeting these requirements is very easy with most diets, so with a healthy balanced diet, there’s usually no need to track your intake of individual amino acids.

For example, one 174-gram piece of braised chicken breast provides a good 55.9 grams of complete protein, which is easily meeting or exceeding the daily needs listed above.

Food sources of essential amino acids

Foods that contain all the nine essential amino acids in an adequate amount ar referred to as complete proteins.

The following foods can be classified as complete protein sources:

  • meat
  • seafood
  • poultry
  • dairy products
  • eggs

Soy, quinoa and pea protein are the plant-based complete protein sources.

Other plant-based sources of protein like beans, nuts, and certain grains, are considered as incomplete proteins because they lack one or more of the essential amino acids.

However, if you’re taking a plant-based diet, you can still easily ensure the proper intake of all the nine essential amino acids which is by eating a variety of plant proteins each day. Moreover this will help to add variety to your daily food.

For example, by eating a variety of plant-based proteins, such as beans, nuts, seeds, whole grains, and vegetables, you can ensure that you meet your essential amino acids’ daily needs, even if you choose to exclude animal products altogether from your diet.


Many animal and plant foods, such as meat, eggs, quinoa, and soy, contain all nine essential amino acids and are thus considered as complete proteins.

Essential amino acids supplement

Amino acid supplements usage is considered safe for most of the people. However, they’re usually not required if you’re getting enough protein in your diet. Most people get enough essential amino acids simply through their diet and thus no such need is seen in general.

However, certain situations do need to get help with certain essential amino acids supplementation. For example essential amino acids supplementation gives excellent results in athletes who often take them to enhance exercise performance and recovery.

Amino acid supplements have several benefits for athletes and non-athletes :

  • Improving athletic performance
  • Developing muscle & strength
  • Reducing delayed onset muscle soreness (DOMS)
  • Limiting fatigue
  • Reducing fat
  • Glucose level balance

One review which included 10 high quality studies found out that doses of BCAAs of up to 115.6 mg per pound (255 mg per kg) per day could help to reduce delayed onset muscle soreness in trained individuals after exercise.

Certain situations need the supplementation of individual amino acids, rather than the whole essential amino acids’ blend, to support certain aspects of health such as mood.

A review which included 11 high quality studies found that taking 0.14–3 grams of tryptophan per day could help to improve mood in healthy people.

As shown by these studies, dosing varies depending on the type of amino acid you’re taking and what your goal is for taking the amino acid.

If you feel the need for taking essential amino acid supplements, you must speak with a healthcare professional who’s knowledgeable about dietary supplements, such as your doctor or more precisely a registered dietitian.

They can recommend specific dosing after careful analysis of your case and tell you the best about taking your supplement, depending on your health goals. This will prove further help as they can help you choose a supplement from a good reputed brand that offers products tested by third-party organizations.


Dosing of amino acid supplements depends on the specific amino acid and your need for taking it. If you’re interested in taking essential amino acid supplements, you must consult a qualified healthcare professional, ideally a dietitian.

Bottom line

There are total nine essential amino acids, which you must get through your diet — histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

They’re vital for a number of functions throughout your body, including protein synthesis, tissue repair, and nutrient absorption.

Some may also offer further help like to prevent muscle loss, support recovery after surgery, and improve mood, sleep, and athletic performance.

These vital nutrients are found in several animal- and plant-based foods, so most people can easily meet their daily needs by eating a healthy, balanced diet. It is also considered safe to take essential amino acid supplements if needed.

Frequently asked questions

What is the best time of day to take essential amino acids ?

The two best times for most people to take essential amino acids’ supplements are between meals and following a workout. For older adults, supplementing between meals is more beneficial to combat the higher rates of protein breakdown common with aging.

Can I take essential amino acids everyday ?

Essential amino acids’ supplements are generally safe to take every day, as long as they are not consumed in amounts more than the daily specific need.

Can essential amino acids be taken on an empty stomach?

Yes, essential amino acids’ supplements can be taken on an empty stomach as that would give the desired results in less time.

Should I take essential amino acids before or after work out ?

 The best time to supplement with essential amino acids is within the first 30 minutes after exercise because it’s the time when your blood flow is very active.

My name is Amanpreet Kaur Samra. M.S. Biochemistry. I'm the founder and writer of this blog. I have been teaching Biochemistry for a good number of years. I started this blog because I have always been very passionate about writing, in particular about Nutrition and Healthy Weight Loss.

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