Do Amino Acid Supplements Work? Benefits & Tips From an RD

Amino Acid Supplements

Supplements are a staple in the fitness industry. Step into any supplement shop and you’ll see protein, creatine, amino acids, and so many more supplements someone will tell you you need to be taking.

Some of these may be total game changers for you and your fitness goals, while others are quite simply not worth the money.

In this article, we’ll review the benefits of taking amino acid supplements, as well as the risks, so you can confidently decide if supplementing is for you.

We’ll also provide recommendations on choosing an amino acid supplement so you can confidently choose one that works for you.

First, let’s answer the question — Do amino acid supplements work? Then feel free to check out our list of the best amino acid supplements

Short Summary

  • Supplementing with amino acids provides benefits, including muscle building, performance enhancement, and decreased soreness
  • There are various subsets of amino acids, including essential amino acids and branched-chain amino acids, that you may choose to supplement
  • Choosing the right supplement for you will provide you the most benefits with the fewest risks

What Is an Amino Acid Supplement?

To start with the basics, amino acids are organic compounds that are the building blocks of protein. When we eat or drink protein in any form, our body breaks it down into amino acids, which are then used to grow new tissue and repair existing tissues, among other functions, within our bodies.

Amino acid supplements are the already broken-down version of these building blocks. These supplements are available either as individual amino acids or a combination of a few amino acids. Most amino acid supplements come in the form of powders, capsules, or pills.

Amino acids are most often taken for performance benefits, including muscle growth, performance enhancement, increased strength, and improved recovery. We’ll dive deeper into these benefits soon.

First, let’s look at a few categories of amino acids.

Essential Amino Acids vs. Branched Chain Amino Acids

Essential amino acids are amino acids the body cannot produce. This means we must consume them from food or supplements in our regimen.

The nine essential amino acids are:

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

In addition to the nine essential amino acids, some amino acids are conditionally essential amino acids meaning that our body can usually produce them, but not always. In times of injury, illness, or stress, they may become essential and need to be consumed.

Conditionally essential amino acids include:

  • Arginine
  • Cysteine
  • Glutamine
  • Tyrosine
  • Glycine
  • Proline
  • Serine

The remaining amino acids are considered nonessential amino acids. These other amino acids do not necessarily need to be consumed because the body can make them. 

Branched-chain amino acids (BCAAs) are a subset of the nine essential amino acids, including leucine, isoleucine, and valine. These amino acids are often supplemented by athletes, bodybuilders, and other active individuals for muscular benefits.

Now that we’ve covered the basics of amino acids, specifically essential amino acids, let’s look at how these supplements work.

Do Amino Acid Supplements Work?

The short answer here is it depends. 

Some research has shown amino acid supplements aid in muscle growth and enhance performance. Other research has shown supplemental amino acids aid with muscle recovery. However, other studies have shown no benefits from supplementing with amino acids.

From a dietitian’s perspective, if you are already meeting your daily amino acid needs through food or protein supplements, you likely will not see the benefit of taking supplemental amino acids. More isn’t always better. However, if you lack, an amino acid supplement may help you meet your needs and see the benefits you seek. 

Let’s dive a little deeper into how these supplements work and what the research says about their use. 

How Do Amino Acid Supplements Work?

Amino acid supplements provide your body with additional protein building blocks above what you consume through food or a protein supplement. The idea behind taking amino acid supplements is to provide a surplus of these components to increase muscle mass, increase strength, and improve recovery.

While supplemental amino acids will give your body more protein building blocks, more is not always better. Gauging your overall protein intake and assessing the need for these additional supplements can help determine if they will truly help you achieve your goals or just be excess.

If you consume a high-protein diet and other protein supplements, you may get all the amino acids you need daily without taking a specific amino acid supplement. However, if you struggle to get enough protein daily, amino acid supplements may help to close this gap.

Another important note: our bodies can only absorb a set amount of protein at a time, so it’s not always beneficial to continue to load up on supplements. Taking an amino acid supplement with a protein shake and a high-protein meal is not the most effective way to maximize your amino acid intake. 

Amino acid supplements, protein powder or shakes, and high-protein foods all contain amino acids that need to be digested and absorbed. Taking them all together in concentrated doses may overwhelm your body and not allow for the maximum nutrient absorption and maximum benefits. 

To get the most out of your protein and amino acid intake, spread them out throughout the day to allow your body to absorb them better. This will give you the best results and help you achieve your goals.       

Do amino acid supplements work? A photo of four powder scoops filled with amino acid powder.

The Benefits of Amino Acid Supplements

Research has shown strong evidence to support supplementing with essential amino acids improves muscle building. Some studies also show that BCAA supplementation can do the same.

Additionally, evidence, although more limited, supports that supplementing with the nine essential amino acids and/or BCAAs can provide additional athletic performance improvements.

Muscle Building

Essential amino acids stimulate muscle protein synthesis. Simply put, these supplements increase muscle mass by helping build new muscle tissue. This can also help achieve the goal of gaining body weight through muscle mass.

To gain these benefits, you must complete resistance training to stimulate growth and take in enough essential amino acids. You can’t have one without the other.

Performance Enhancement 

Essential amino acids and BCAA supplements have been shown to enhance athletic performance when taken during prolonged exercise by decreasing the perception of muscle fatigue during training. This allows you to train longer and harder to see more benefits from your training.

Decreased Muscle Soreness

BCAA supplementation has also decreased delayed onset muscle soreness after weight training. Soreness is often the result of muscle damage, but supplementing may aid in muscle recovery, tissue repair, muscle synthesis, and repairing body tissue and get you back into the gym faster.

Image of a woman exercising by hanging from a pull-up bar.

Are Amino Acid Supplements Safe? Are There Side Effects?

Generally, amino acid supplements taken in recommended serving sizes are considered to be safe for most people. However, as with most supplements, over-supplementation may have side effects and should be avoided.

Additionally, certain groups, including the elderly, children, and pregnant or breastfeeding individuals, are likelier to have adverse effects from supplements. Anyone with diabetes or liver disease is also cautioned against taking amino acid supplements.

Digestive issues are one of the most notable side effects of over-supplementing amino acids. This may include nausea, pain, and/or diarrhea. 

Excess supplementation can also affect other organs, including the liver, kidneys, and brain. More serious side effects can also occur with long-term over-supplementation.

How to Choose an Amino Acid Supplement

Multiple factors go into choosing the best supplement for you.

First, determine if you are looking for an essential amino acid or a BCAA supplement. Remember, essential amino acids include all three BCAAs and have similar benefits, so you may find it best to select an essential amino acid supplement.

Other factors to consider include the product quality, which is often directly related to the quality and reputation of the company producing the supplement. Looking for supplements that are third-party tested helps ensure quality, purity, and effectiveness because supplements are less regulated than food products. 

The other ingredients in the supplement are also important to look at. Ideally, a supplement should have a few added ingredients like flavors, colors, and sweeteners. Supplement form is also a matter of personal preference. You can choose powder, capsule, or pill. 

Supplements can also get expensive, so finding something high quality in your price range is key.

A photo of a healthy meal consisting of red meat, egg, and beans.

Food Sources

As a registered dietitian, I encourage a food-first approach. We all know that a healthy diet provides health benefits. 

Your foundation should be a nutritious diet, and dietary supplements should be used to fill gaps in your diet. With that said, before turning to supplements, be sure you are eating a high-quality, balanced diet that is rich in complete protein sources to ensure you are getting all the amino acids, including both essential amino acids and BCAAs that your body needs.

All foods that contain protein inherently contain amino acids, so including high-quality protein sources like meat, fish, eggs, dairy, beans, and soy will boost your intake of amino acids. Animal proteins are considered complete proteins that provide all amino acids, so focusing on these foods can help ensure adequate nutrition even without a dietary supplement.

If you feel that you need supplemental amino acids on top of your dietary intake to achieve your goals, finding a high-quality supplement using the guidelines above may help you achieve your goals.


Amino acid supplements can provide athletes, bodybuilders, or general fitness lovers with muscular benefits, including muscle growth, muscle development, protein synthesis, performance enhancement, and decreased soreness.

Deciding which subset of amino acids is right for you is key. Additionally, choosing a high-quality supplement will provide the maximum benefit with the lowest risk. Be sure to stick to supplementation guidelines and avoid over-supplementing, which also comes with health risks.

As with most supplements, taking a food-first approach that prioritizes amino acids by prioritizing protein will help ensure a well-rounded diet and a healthy body.


Is it OK to take amino acids every day?

Generally, yes, it is safe to take an amino acid supplement daily. We all eat amino acids daily when we consume foods containing protein, so there is nothing foreign about ingesting amino acids daily.

However, over-supplementation does come with risks, and more is not always better, so stick to the recommended serving sizes.

Who should not take amino acids?

Amino acid supplementation can be risky for some populations, including:

  • Elderly
  • Children
  • Pregnant 
  • Breastfeeding 
  • Those with diabetes
  • Those with liver disease 

How long does it take for amino acids to start working?

Your body will start absorbing amino acids as soon as you take them. However, you won’t start to see the muscular benefits immediately.

Within a few weeks of starting the supplement, you will likely start to see its benefits. We recommend taking the supplement for at least 30 days before determining if it provides you the benefits you are looking for. At that point, if you are not seeing benefits, it may be time to try a different supplement.


HOLEČEK, M. “Side Effects of Amino Acid Supplements.” Physiological Research, 22 Mar. 2022, pp. 29–45,,

Kerksick, Chad M., et al. “ISSN Exercise & Sports Nutrition Review Update: Research & Recommendations.” Journal of the International Society of Sports Nutrition, vol. 15, no. 1, 1 Aug. 2018,,

MedlinePlus. “Amino Acids: MedlinePlus Medical Encyclopedia.”, 

Weber, Martim Gomes, et al. “The Use of BCAA to Decrease Delayed-Onset Muscle Soreness after a Single Bout of Exercise: A Systematic Review and Meta-Analysis.” Amino Acids, vol. 53, no. 11, 20 Oct. 2021, pp. 1663–1678,

Liz Cook | Registered Dietitian

Liz Cook | Registered Dietitian

Liz is a registered dietitian and freelancer health and wellness writer. She holds a BS in Nutrition from Penn State University, as well as a MS in Nutrition from Northeastern University. She has worked as a dietitian in a variety of settings including private practice, corporate wellness, and campus dietitian at Grand Canyon University.

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