Essential Amino Acids: A Complete Guide

Essential Amino Acids: A Complete Guide

Are you looking for a way to improve your health? 

Then you’ve probably heard the term “essential amino acids” before, but do you know what they are and why they are so important? 

Whether you’re an athlete looking to improve your performance, a vegetarian or vegan seeking to meet your nutritional needs, or simply someone interested in maintaining optimal health, essential amino acids are the key. 

This comprehensive guide will explore everything you need to know about essential amino acids – what they are, how they work, why they are essential, and where to find them in your diet.

So, let’s dive in and discover the fascinating world of essential amino acids!

What are Amino Acids?

What are Amino Acids
Source: Canva

Amino acids are the fundamental building blocks of proteins, and they serve as the nitrogenous backbones for compounds like neurotransmitters and hormones. These organic compounds are composed of nitrogen, carbon, hydrogen, and oxygen. 

Each amino acid has a unique structure and function. They are connected in specific sequences to form different types of proteins, each with a specific function in the body. 

Our body needs twenty amino acids to grow and function properly. Out of these, nine amino acids are referred to as Essential Amino Acids (EAAs) as our body can not make them on its own hence we must obtain them through diet or supplements. The human body can synthesize the remaining amino acids using only the essential amino acids. 

However, certain non-essential amino acids are considered conditionally essential, meaning they may become essential only in certain situations, such as during illness or stress.

Here is the amino acid classification for your quick understanding.

Essential Amino AcidsConditionally Essential Amino AcidsNon-Essential Amino Acids

What are Essential Amino Acids?

Essential Amino Acids
Source: Canva

Our body cannot produce these amino acids independently, which can be obtained through diet. The nine essential amino acids are:

  • Histidine
  • Isoleucine
  • Leucine
  • Lysine
  • Methionine
  • Phenylalanine
  • Threonine
  • Tryptophan
  • Valine

These essential amino acids play a critical role in many bodily functions, including building and repairing tissues, producing hormones and enzymes, and maintaining a healthy immune system. Without these essential amino acids, our bodies cannot function properly.

Role of Essential Amino Acids in our body

Role of Essential Amino Acids in our body
Source: Canva

Every essential amino acid has a significant role to play in our body.


Histidine is utilized by the human body to synthesize histamine, which is essential for various bodily functions. In addition to its role in energy metabolism, histidine is also involved in the production of hormones and metabolites that impact kidney function, nerve transmission, stomach secretions, and the immune system. Moreover, histidine contributes to tissue repair and growth, supports the production of blood cells, and aids in protecting nerve cells.


This branched-chain amino acid is essential for the formation of hemoglobin and the production of red blood cells. It also plays a vital role in immune function, protein, fat, and carb metabolism, and detoxifying nitrogenous waste like ammonia. 


Leucine is necessary for overall muscle health. It stimulates muscle protein synthesis, prevents muscle breakdown, and encourages insulin secretion to support healthy blood sugar levels.


By blocking stress response receptors, this essential amino acid assists in reducing anxiety levels. Our body also utilizes lysine for collagen synthesis necessary for healthy skin, bones, joints, and ligaments. Lysine is also believed to strengthen bone health by increasing calcium absorption and retention.


This sulfur-containing amino acid is required for tissue growth and formation. Furthermore, it is critical in absorbing potent antioxidants such as zinc, glutathione, selenium, and the amino acid cysteine.


Phenylalanine is a precursor to neurotransmitters like dopamine, norepinephrine, epinephrine, and tyrosine. It also plays a crucial role in synthesizing proteins and amino acids.


Threonine aids in creating collagen, elastin, and muscle tissue. This amino acid is highly beneficial for the smooth functioning of the immune and central nervous systems. 


As the sole precursor of serotonin, tryptophan is essential in mood, behavior, cognition, and maintaining a healthy nitrogen balance.


Valine is one of three BCAAs (branched-chain amino acids) that enhance energy, increase endurance, and aid muscle tissue recovery and repair. 

Health benefits of supplementing with Essential Amino Acids (EAAs)

Health benefits of supplementing with Essential Amino Acids
Source: Canva

Better muscle health

Studies suggest that taking essential amino acid (EAA) supplements and a regular exercise routine may promote muscle growth and development while reducing body fat.

Prevent muscle loss

Essential amino acids are significant in preventing muscle breakdown and preserving lean body mass. They are especially beneficial for older adults on bed rest or recovering from prolonged illness. 

Boost athletic performance

Numerous clinical trials have proven that supplementing with essential amino acids can help alleviate fatigue, enhance exercise performance, and promote muscle recovery after exercise.

Promote sleep health

Essential amino acids like tryptophan and histidine help regulate the sleep-wake cycle and have been shown to reduce symptoms of depression and improve mood.

Dietary sources of Essential Amino Acids (EAAs) 

Dietary sources of Essential Amino Acids
Source: Canva

Food sources of protein containing all nine essential amino acids are termed complete protein. Besides supplements, we can also get essential amino acids through protein foods like:

Meat: Animal proteins are one of the best sources of EAAs. Beef, pork, chicken, and lamb are excellent sources of all nine essential amino acids. They also contain a high amount of protein, which helps in muscle building.

Fish: Fish is another excellent source of EAAs, particularly omega-3 fatty acids, essential for heart health. Salmon, tuna, sardines, and mackerel are rich in EAAs and provide other essential nutrients like vitamin D and calcium.

Eggs: Eggs are among the most nutritious foods, providing a wide range of vitamins and minerals, including all nine EAAs. They are an excellent source of protein and can be easily added to your diet in various forms, such as boiled, scrambled, or poached.

Dairy products: Milk, cheese, and yogurt are all rich in essential amino acids, particularly leucine, vital for muscle building. They also provide a good source of calcium, which is essential for strong bones and teeth.

Beans and Legumes: Vegetarians and vegans can get their EAAs from beans and legumes like lentils, chickpeas, and kidney beans. They are rich in protein, fiber, and iron, making them an excellent addition to any diet.

Nuts and seeds: Nuts and seeds are a healthy snack that provides a good source of essential amino acids, particularly tryptophan, vital for mood regulation. Almonds, cashews, pumpkin seeds, and chia seeds are some of the best options.

Quinoa: Quinoa is a gluten-free grain rich in all nine essential amino acids, making it an excellent plant-based source of protein. It’s also a good source of fiber, iron, and magnesium.

The recommended dosage of Essential Amino Acids (EAAs) 

recommended dosage of Essential Amino Acids
Source: Canva

The recommended dosage of Essential Amino Acids (EAAs) can vary depending on age, gender, body weight, physical activity level, and overall health status. However, some general guidelines can be followed.

One must meet the daily recommended allowance of these amino acids to prevent any deficiency, as our body can not produce them. 

As per ICMR, these are the RDA (Recommended Daily Allowance) values for amino acids. AcidsRDA (mg/kg body weight/day)

What Happens if You Don’t Get Enough Essential Amino Acids?

if You Don't Get Enough Essential Amino Acids
Source: Canva

If you don’t get enough essential amino acids in your diet, it can lead to a range of health problems. Here are some of the consequences of a deficiency in essential amino acids:

Muscle loss: A lack of essential amino acids can lead to muscle loss and weakness.

Slow wound healing: Amino acids are essential for building and repairing tissues. Without enough essential amino acids, wounds may take longer to heal.

Hormone imbalances: Amino acids are involved in the production of hormones. Without enough essential amino acids, hormone imbalances can occur, leading to a range of health problems.

Weak immune system: Amino acids are necessary for producing antibodies, which help the body fight off infections. A lack of essential amino acids can weaken the immune system and increase the risk of infections.

Fatigue and weakness: A lack of essential amino acids can lead to fatigue and weakness, making it difficult to carry out daily activities.

Why Should You Supplement With EAA?

Why Should You Supplement With EAA
Source: Canva

Supplementing with essential amino acids (EAAs) has become increasingly popular in recent years due to their numerous benefits for overall health and fitness. 

Here are some reasons why you should consider adding EAA supplements to your diet:

Promotes Muscle Growth: EAAs are the building blocks of protein, and supplementing with them can help promote muscle growth and repair. This is especially important for individuals who engage in regular exercise or weightlifting.

Reduces Muscle Breakdown: EAAs can also help reduce muscle breakdown, making them an effective supplement for individuals seeking to preserve lean body mass.

Increases Endurance: Supplementing with EAAs has increased endurance, allowing individuals to exercise for extended periods and at higher intensities.

Aids in Recovery: EAAs are essential for muscle recovery, and supplementing with them can help reduce muscle soreness and fatigue after exercise.

Improves Mood: EAAs like tryptophan and histidine can help regulate the sleep-wake cycle and improve mood. This makes them a valuable supplement for individuals who suffer from depression or sleep disorders.

Helps with Weight Loss: EAAs can help promote weight loss by increasing metabolism and reducing appetite. This can be especially helpful for individuals looking to lose weight while preserving their muscle mass.

Provides a Convenient Source of Protein: EAA supplements provide a convenient and high-quality source of protein, making them an excellent option for individuals who may not be getting enough protein through their regular diet.

Supports Overall Health: EAAs play a vital role in overall health, and supplementing with them can help support immune function, improve gut health, and support the health of hair, skin, and nails.

Safe and Effective: EAA supplements are generally safe and effective and have been shown to have few side effects when taken at recommended doses.

Can Excessive Intake of Amino Acids Be Harmful?

Excessive Intake of Amino Acids Be Harmful
Source: Canva

While amino acids are generally safe and beneficial for our health, excessive consumption or certain medical conditions can cause harm. 

Below are some of the harmful effects of amino acids:

  • High levels of amino acids in the bloodstream can lead to an increased workload on the liver and kidneys, which may lead to liver or kidney damage in some cases.
  • Overconsumption of specific amino acids, such as arginine and methionine, has been linked to an increased risk of cardiovascular diseases, including heart attacks and strokes.
  • Taking excessive amounts of amino acid supplements, especially isolated amino acids, may cause imbalances in the body’s natural levels of other amino acids, leading to digestive issues and adverse effects on metabolism.
  • Some amino acids, such as phenylalanine, can harm individuals with certain genetic disorders, such as phenylketonuria (PKU). PKU is a rare genetic disorder in which the body cannot properly metabolize phenylalanine, leading to toxic buildup and severe neurological damage.
  • When taken in large amounts, Amino acid supplements can interact with medications and cause adverse side effects. For example, arginine supplements can increase the risk of bleeding in individuals taking blood-thinning medications.
  • Excessive consumption of amino acids can also lead to the formation of harmful byproducts such as acetaldehyde and ammonia, which can damage the liver and other organs.

Wrap Up 

Essential Amino Acids: A Complete Guide
Source: Canva

The diet should prioritize protein intake for fitness, weight loss, and muscle gain goals. One can consider supplementing with essential amino acids as a convenient and effective method to boost daily protein consumption with a premium source of amino acids.

What is the role of essential amino acids in our body?

They’re vital for functions throughout your body, including protein synthesis, tissue repair, and nutrient absorption. Some may also help prevent muscle loss, support recovery after surgery, and improve mood, sleep, and athletic performance.

Do you need all essential amino acids at every meal?

You do not need to eat essential and nonessential amino acids at every meal, but getting a balance of them over the whole day is important. A diet based on a single plant item will not be adequate, but we no longer worry about pairing proteins (such as beans with rice) at a single meal.

How many essential amino acids does the body need each day?

They are the molecules that all living things need to make protein, and you need 20 of them to help your body function properly. Your body makes 11 of the necessary amino acids. The good news is you don’t have to do anything special to get the remaining nine amino acids your body needs.

Why can’t the body make essential amino acids?

Essential amino acids, also known as indispensable amino acids, are amino acids that humans and other vertebrates cannot synthesize from metabolic intermediates. These amino acids must be supplied from an exogenous diet because the human body lacks the metabolic pathways required to synthesize these amino acids.

Which part of amino acid gives its uniqueness?

The difference in the side-chain group or R-group is what determines the unique properties of each amino acid.

What amino acids should not be taken together?

L-lysine, for example, competes for cell receptors with L-arginine, so they’re best used separately. Other amino acids that shouldn’t be combined are tryptophan and phenylalanine or tyrosine, taurine and glutamic acid or aspartic acid, carnitine and tyrosine, and cysteine and lysine.

7 High Protein Grains to Try Instead of Rice 7 Reasons to Consume 2 Soaked Dry Dates Every Morning Foods & Drinks to Consume on an Empty Stomach 7 Best Coffee Recipes for Weight Loss 7 Tips to Keep Eyes Healthy Despite Prolonged Screen Time