Amino acids play a vital role in muscle building, fat loss, and overall fitness. In this article, we break down what they are, their effect on the body, and their benefits.

You've probably seen new gym-goers, gym bros, and advanced lifters adding powdered BCAAs into their shakers before, during, and after workouts. You've also probably seen amino acid jargon printed on the label of your go-to protein powder. Everyone has heard of them, but few people truly know the importance amino acids have in helping you achieve your fitness goals

What Are Amino Acids?

Amino acids are the building blocks of protein and muscle tissue. They play a major part in physiological processes relating to our energy, recovery, mood, brain function, muscle and strength gains, and even in our quest for fat loss.

There are 20 amino acids, and 9 of these are classed as essential or indispensable amino acids (IAA) that must be obtained from our nutritional intake. The others are termed dispensable amino acids (DAA), or non-essential, due to the body being able to synthesize them from other amino acids.

Graphic of the structures of the 20 amino acids.

Different Ways to Consume Amino Acids

Amino acids are found in the food you eat and the supplements you take. Protein-rich foods such as lean meats, non-fat dairy products, and protein drinks are the most common ways that we get our amino acids. We can also obtain amino acids from vegetables and legumes. Additionally, protein drinks and amino acid supplements can serve as a convenient means to supplement our dietary needs.

Many of us don't consider the amino acid content and balance of our food, but the amino acid content of our meal is an important factor in supporting maximum muscle growth; however, it is not the only factor to take into consideration. You also have to factor in the extent that the amino acids are delivered to the tissues where they are needed. This brings us to the bioavailability, digestion, and absorption of amino acids by the body. 

Bioavailability, Digestion, and Absorption of Amino Acids


From pre-packaged amino acid workout and recovery drinks to powdered amino acids in the gym bags of fitness enthusiasts across the world, it is safe to say that the popularity of amino acid supplements has dramatically increased over the past several years. The main reason we use supplements is the bioavailability of the amino acids. Bioavailability is the measure of a substance's ability to be absorbed by the body. Two factors determine amino acid bioavailability:

  1. How much fat is contained in the protein source
  2. The length of time it takes for the amino acids to be available for use by the body

Digestion and Absorption

The good thing about supplements, like powdered or capsuled BCAAs, is that they don't require digestion like food does. Most supplements contain free-form amino acids meaning they are free of chemical bonds to other molecules and move quickly through the stomach into the small intestines where they are very rapidly absorbed into the bloodstream.

When absorbed, amino acids are processed by the liver. However, the liver can only process so many amino acids at one time. If you consume a dose of amino acids that exceeds the liver's capacity, the amino acids will be redirected to the muscles. A dose of 3-4g of amino acids is enough to achieve this result.

Several factors contribute to the absorption rate of amino acids:

  • Cooking of foods
  • Whether the food is a solid, liquid, powder, or even tablet
  • The extent to which the amino acid is chemically pre-digested
  • Fillers and binders present in the food/supplement
  • Digestive system health

Muscle and Strength model wearing a blue M&S tank and black shorts scooping supplement powder into shaker cup.

Benefits of Amino Acids

Provides Source of Energy

A lot of misconceptions exist about the use of energy substrates during heavy, high-intensity weight training. When performing your training with repetitive, power workouts, a substantial portion of your energy comes from non-carbohydrate sources. When your muscles contract, they use stores of adenosine triphosphate (ATP, a substance vital to the energy processes of all our living cells) for the first few seconds. These stores are immediately replenished by creatine phosphate (CP). This biological process is how the supplement creatine became so popular with bodybuilders and strength-trained athletes.

Creatine is made from three amino acids: arginine, methionine, and glycine. To keep our CP and ATP levels high, these amino acids must be kept elevated in our bloodstream. The amino acids in creatine supplements can be supplied by foods in our diet, but the process of elevating these amino acids takes a great deal of time in digestion and also would be accompanied by fats and carbohydrates. So, the use of free form amino acids, either alone or in combination with creatine supplements, can provide a direct source of energy for power and strength.

Related: Creatine Supplements Guide

Prevents Muscle Breakdown

Our body has the ability to break down our muscle tissue for use as an energy source during heavy exercise. This is part of a bodily process called gluconeogenesis, which means producing or generating glucose from non-carbohydrate sources. The part of this reaction that is important to us as bodybuilders is known as the glucose-alanine cycle. In this process, the BCAAs are stripped from the muscle tissue and parts of them are converted to the amino acid alanine, which is then transported to the liver and converted into glucose. If we consume supplemental BCAAs, the body does not have to break down our muscle tissue to gain extra energy. Studies have concluded that the use of up to 4g of BCAAs during and after training can result in a significant reduction of muscle breakdown during training. Catabolism of muscle can cause shrinkage of our muscles and muscle soreness and may also lead us to injury.

Muscle & Strength model wearing grey M&S t-shirt doing cable tricep pushdowns.

The Importance of Amino Acids in Muscle Growth

Muscle growth is caused by exercise, hormones, and nutrients. Resistance training generally stimulates both protein synthesis and protein degradation in exercised muscle fibers. The normal hormonal environment (e.g, insulin and growth hormone levels) in the period following resistance training stimulates the muscle fibers' anabolic processes while blunting muscle protein degradation. Dietary modifications that either increase amino acid transport into muscles or increase anabolic hormones should augment the training effects by increasing the rate of muscle anabolism and/or decreasing muscle catabolism. Either effect will create a positive body-protein balance for improved muscle growth and strength.

Supplementation of free form amino acids that are high in the branch chain amino acids (BCAAs)  Leucine, Isoleucine, and Valine will also assist in muscle growth. The ideal time to consume amino acids is immediately after training when the muscle is especially receptive to nutrients and blood flow to the exercised muscles still remains high. After training, muscle growth and recovery can be optimized with a meal consisting of a fast-digesting protein and both simple and complex carbohydrates. Whey protein is a great option for fast-digesting protein.

The Role of Amino Acids in Fat Loss

In fat loss, two major processes must occur:

  1. The mobilization and circulation of stored fats in the body must be increased
  2. Fats must be transported and converted to energy at the mitochondria (the powerhouse site of cells)

Several nutrients can assist in the conversion of fat to energy including the amino acid methionine, which in sufficient amounts can help improve the transport and metabolism of fat. When attempting to keep your total calories down during dieting, amino acid supplements, including BCAA's and glutamine, can also help to keep our food volume down but still provide support directly to the muscles, liver, and immune systems, which are critical to optimizing our body composition.

  1. Amino Acids & Bodybuilding. Barry Finnin, PHD. and Samual Peters.
  2. Exercise physiology. 5th Edition, William D, McArdle. Frank I Katch, Victor L Katch.


Posted on: Wed, 01/27/2021 - 18:42

Do protein shakes have sufficent amino acids to help with muscle gain or fat lose? Or should I take BCAA supplements as well? Thanks!

Posted on: Sat, 07/23/2016 - 01:59

can i take amino 2222 even if i am under antibiotic teraphy?

Posted on: Sun, 01/03/2016 - 05:12

Can we use fat burner and amino acide 2222 in the same time?

Posted on: Thu, 08/13/2015 - 04:28

Doug, I am 78 close to79 years old. Played most sports, had a knee replacement 3 years ago ,no good can onlyj just bend my leg, but work out 2 days a week at local gym doing leg exercises and upper body work. play golf twice a week walking the course. I take body science strength protein blend after workout .I think that after 5 weeks I have noticed an increase in my muscles in my arms and legs.. can a old man like me gain muscle and benefit from the protein drink. regards Bob

Posted on: Mon, 10/19/2015 - 04:21

U r still alive and by doing exercise and use extra weight and doing little weight training u can add muscle like others and its not srange. Good luck

Posted on: Fri, 02/06/2015 - 14:03

How to take on amino softgels 2222 this is a soluble or chewable

Posted on: Fri, 12/12/2014 - 11:14

I would like to know if I can take pea powder with all the amino acids if I'm 60 yrs old and if I don't exercise?

Thank you!


Posted on: Wed, 12/10/2014 - 07:38

Hey i am 1.70m tall and my weight is 64 kilos. Im 15 years old. 1 Year ago i was like 75 kilos but now im in good shape. I constatly run and swim. 2 Months ago i started in the gym and gained some muscles really fast i mean my arm became huge for just that small period (i guess because it was huge when i was fat but now the muscles are defined well). I want to ask what supplements can i take for building the muscles faster. I eat lots of vegetables,fruits, eggs, meat, drink watter like a lot and also take Magnesium, Calcium, Zinc and Multivitamins. Can amino acids help me build muscles faster or convert some fat to muscle ? Also is it true that you can grow a little bit taller with amino acids ? Because as far as i know proteins are built from Amino Acids.
Thank you.

Posted on: Fri, 08/22/2014 - 22:01

i am only i am training 5 days per week.i want to become it safe by using serious mass with amino 2222 tab.will it gives any result.???

Posted on: Tue, 05/20/2014 - 11:53

Steve, I'm 5'7 174lbs (my bf % is 13.4) and im trying to lose more fat. I'm taking amino acids and whey protein. I work out 6 times a week and I do cardio 20 to 30 mins after I work out. what kinda lose fat do you recommend? please help. thanks

Posted on: Sat, 04/26/2014 - 00:13

I work construction and it is very labor intense and most days I feel heavy fatigue halfway through. I was thinking of taking amino acid for that much needed energy. Would amino acid be the best thing to take or would you recommend something else?

Posted on: Mon, 04/14/2014 - 01:18

hey im a 15 YO guy and taking 3 times a day of amino acid 2222 is it ok?

Posted on: Tue, 04/01/2014 - 07:56

hi steeve I am using Aminopur Powertabs 1600 .. can you tell me what are the effects and how to better use (how many times and when)
I am waiting in your answer, I really need your answer ...

atul arya
Posted on: Wed, 03/12/2014 - 13:45

answer my question steve

atul arya
Posted on: Wed, 03/12/2014 - 13:39

steve what is the best time to take amino tablets......actully i m taking amino tablet in mrng time after breakfast and one in evening time before workout is it okey........

Posted on: Sun, 02/16/2014 - 15:00

Hi Steve I am 45 and I weigh 230 lbs . I wanna loose 45 lbs and I have done that in past 6 yrs ago. I am thinking of Lipo6 , what other supplements I should take with it like multivitamins and others to help me loose weight.

Posted on: Fri, 01/24/2014 - 21:41

I'm trying to get toned and build muscle, is it okay if im taking NLA for her fat burning pills and amino acids but no whey protein? or is it best to take the whey protein as well with them?

Posted on: Wed, 01/15/2014 - 10:18

Hi i used whey protein with multivitamin and the i used two month supplement gain fast but no result now one of my friend gave me amino max 8000 and im using this from one week and im going in gym with routine in the night around 03 am after my evening duty and after gym im sleeping.
the food im eating is provided by the company where im working and thats not good food but i have to manage with its even i dont like to eat it.
do i need any thing els to take with aminomax 8000?.
how i can burn the fat around the belly.
plz advise me.

Posted on: Thu, 01/02/2014 - 16:24

Hi Steve,

This is Ravi and i am gyming hard and i am taking Mass Tech from Musceltech.just wanted to know is Mass tech good for gaining muscle mass? or can i add Amino build too?

Posted on: Sat, 11/30/2013 - 03:22

I lost weight on my hips and butt from a cleanse I did...I am ok with the result, however I just dislike that I lost too much fat on my butt that makes it look uneven and it kinda has hole/ line that fat is needed.will amino acid help digest all my food all over my body?

Posted on: Wed, 10/30/2013 - 10:55

I want to ask about amino 24000 .. is it good to have or it is more stronger that I should have ???

yasser fouad
Posted on: Sat, 10/26/2013 - 18:53

can I gain muscles while taking lipo 6 black and will it burn my muscles?

Posted on: Fri, 09/06/2013 - 09:18


Posted on: Wed, 08/07/2013 - 20:27

Currently taking ON Amino many pills should I be consuming for maximum effect...currently working out 5-6 days a week....7-8 tabs pre and post this safe and is it effective?

Posted on: Sat, 07/27/2013 - 13:57

What are your thoughts on the aminos that universal animal pak has to offer?

Posted on: Sun, 07/21/2013 - 20:15

I am taking super pump and amino2222 is it fine?
And can you lease tell me what amino2222 Actually does? Thanks

Posted on: Sun, 07/21/2013 - 20:15

I am taking super pump and amino2222 is it fine?
And can you lease tell me what amino2222 Actually does? Thanks

Posted on: Tue, 07/02/2013 - 07:52

hi im work out at the gym and also take serious mass will amino help further in building muscle

clark dominic
Posted on: Fri, 06/21/2013 - 03:38

i am a 24-year-old man weighing 140 pounds. I have been lifting for 1 year and 8 months. i want 2 ask: How many grams of amino acids do you recommend me 2 take every post-workout? Let's say for exmple: i'm training 4-5 times a week with only 1 - 1.5 hours every session....

Ricardo Narine
Posted on: Tue, 06/11/2013 - 13:30

Hey, Steve......
i am taking universal amino acids 1000 gram capsules and i want to know if it helps me with growth as well
i am 15 Years old and 5 foot tall
will it help me with growing

Posted on: Sat, 06/08/2013 - 23:14

hi! i m using on platinum pre and gold standard whey protein..i want to add amino acid and casein also...can u suggest me abt amino acid ...i have muscular body and height 5'11 nd weight around 70 kg...

Posted on: Sat, 06/01/2013 - 06:37

hey mate ijst wanna know if I can take L Arginine nd Lipo 6 Black together nd how to take it thanks

Posted on: Tue, 05/28/2013 - 05:46

is ok if i use an amino,,, ??? is this not affected my sperm cell???

Posted on: Sat, 05/18/2013 - 01:04

Hi Sir Steve,
Supplements are epensive, so if i were to chose from amino acids or creatine, what would you recommend?
Thanks and more power.

Posted on: Tue, 04/09/2013 - 12:55


fauad saleem
Posted on: Sun, 03/31/2013 - 08:27

Hi ... i just bought amino acids 2222 softgels and now i m getting confused if it does not effect your inner body or does not have side effects ... actually i m getting mixed reviews from my environment ... so please any one can guide me on this ... i will be very thankful.

Posted on: Sun, 03/31/2013 - 04:18

Can i take amino acid 5600 and any weight gainer at the same time?

Posted on: Wed, 03/20/2013 - 14:39

Hey hi i m mahesh and wanted to take amino 2222 is its really work 100 percent for making strong muscle

Posted on: Wed, 03/13/2013 - 15:19

iam 82 years old and i have nerve problem originating in my cervcal, running thru my right arm , i like to know if i can take l-theanine amino acid to release my 24 hours pain ,t hank you

Posted on: Fri, 03/08/2013 - 02:11

suggest me the best whey protein to build pure muscle..

Posted on: Thu, 01/31/2013 - 15:46

Can I take Hydroxycut Hardcore with AMINO 2300?

M&S Team Badge
Posted on: Thu, 01/31/2013 - 19:05

There shouldn't be an issue. Amino acids should not have any adverse reaction with Hydroxycut. Double check on the product labels for any warnings, however.

Posted on: Sun, 12/23/2012 - 15:15

Is Amino 6000 good for building mass?

Posted on: Wed, 12/19/2012 - 01:05

Hi Steve hey one question: what works better protein shakes or amino acids???

D Goodrow
Posted on: Fri, 11/16/2012 - 19:58

I starting to take BCAA Complex 2200. Is it good to take 1000 mg of Fish Oil with this product? Thanks....

M&S Team Badge
Posted on: Thu, 11/29/2012 - 19:20

BCAA's can be taken as a stand alone supplement, and you can take the fish oil with your BCAA's if you wish. I recommend that you take fish oil with food, however.

M. Khatib
Posted on: Mon, 10/22/2012 - 12:23

I am aiming to lose fats from around the muscles by taking amino acids and grow by whey protein .. what type of amino acids shoupd I take and how many pills per day? and I just want to know how many grams of amino acids should I take daily, I mean the range ..


Posted on: Mon, 09/24/2012 - 03:28

I just had knee scope surgery. I had a torn meniscus. I'm tryn to recover quickly. Can I take a amino acid suppliament & will it help me regain my strength back????

Posted on: Fri, 09/14/2012 - 02:45


I'm a young guy just starting out trying to gain muscle mass. Currently, I am taking a pre-workout supplement and a post-workout recovery drink. I admit that today, I just found out that I should add amino acids to my workout. My question is, I guess I know so little about what to take so in your opinion in addition to pre-workout supplement, recovery drink and amino acids, what else is crucial to be taking for mass gain?

Posted on: Thu, 09/06/2012 - 00:23

Is it okay to stack, whey protein, amino 1000, L-glutamine and creatine x3?