Are They Proper for You?

19 0
A Venn diagram showing the types of amino acids, including essential amino acids, branched chain amino acids, conditionally essential amino acids, and non-essential amino acids.

Definition | Do you work? | BCAAs against whey | BCAAs vs. EAAs | BCAAs against food | Bottom line

"Let BCAAs surprise you," says the company that sells them.

"I took BCAAs and had a lot more gains," says the gym man.

"Taking BCAAs twice a day helps recovery," says fit human on Twitter.

With all this talk, it's enough to ask any muscle-conscious person: Should I take a BCAA (Branched Chain Amino Acid) supplement?

Unless you're a molecular biologist specializing in muscle building. (This is me.)

Or you are someone like Stuart Phillips, PhD, one of the world's leading protein researchers. He is the principal researcher in McMaster University's protein metabolism lab – one of the most productive protein metabolism labs in history. He publishes more than 250 research papers that have been cited more than 32,000 times.

When making BCAA claims, people often cite research from Dr. Phillips.

Dr. However, Phillips doesn't recommend BCAA supplementation – for nothing.

If the BCAA expert doesn't recommend it, why do so many people swear by the supplement?

And what other, cheaper options might work as well or better?

Let's find out.

What are branched chain amino acids (BCAAs)?

Before we dive into BCAAs, let's look at amino acids in general.

Amino acids are the building blocks for protein. There are 20 different amino acids, which are divided into three categories.

Amino acids can be divided into three categories: essential amino acids, conditionally essential amino acids, and non-essential amino acids.

Your body can make some amino acids – these are called "non-essential" – but others must be obtained from food. These are called essential amino acids. Conditionally essential amino acids can sometimes be produced by the body, but not during stressful times – like after a hard workout or when you are sick.

Branched Chain Amino Acids (BCAAs) are a subgroup of three essential amino acids (EAAs):

  • Isoleucine
  • Leucine
  • Valine

Of the three BCAAs, leucine is the most researched and appears to offer the greatest physiological benefit. It stimulates muscle protein synthesis when muscle cells assemble amino acids into proteins. This process is key in building muscle strength and size.

At the turn of the millennium, Dr. Phillips one of several researchers who found that leucine was the star of the muscle building show because of its stimulatory effects on protein synthesis

When his and other studies were published, people in the muscle building universe were excited.

Your thinking went like this:

But wait, muscle building universe – don't get too excited …

over 150,000 Health and Fitness Professionals Certified

Save up to 30% on the best nutrition education program in the industry

Gain a deeper understanding of nutrition, the authority to coach it, and the ability to turn that knowledge into a thriving coaching practice.

Learn more

Do BCAAs Work?

Probably not – for many reasons. We will only go into three of them here.

Reason # 1: Leucine cannot build muscle without other amino acids.

Here's an analogy: think of muscles as a wall.

Granted, this will be an unusual wall that someone builds and destroys over and over – but still visualize a wall.

When it comes to building this wall, leucine is the most important building block. The wall will not be built without it.

But leucine cannot do the job on its own. You will also need histidine stones, lysine stones, methionine stones, and many other amino acid stones.

What if you just have a bunch of leucine stones? Now everyone.

When you have a bunch of leucine, isoleucine, and valine (the BCAAs)? Still no wall.

You will need stones made from all 20 amino acids.

Bottom line: To build muscle, you need all amino acids, not just leucine.

Reason # 2: Leucine doesn't work like lighter liquids.

People mistakenly assume that the more leucine (made from BCAAs, EAAs, or whole protein) you ingest, the more protein synthesis you get. And more protein synthesis means bigger muscles.

Light these muscles, baby!

Except that the mechanism is more like a dimmer, explains Dr. Phillips.

Leucine will turn the protein synthesis switch on – but not indefinitely.

It doesn't keep making the lights brighter and brighter until just you and the sun are hanging in the gym and infinitely more puffy.

Here's how it actually works:

About 0.5 grams of leucine turn on the light and initiate muscle protein synthesis. You will find as much in an egg – or any other food that contains at least 5 grams of complete protein

You will maximize your performance somewhere around 2-3 grams of leucine, although the exact amount will vary based on your gender, height, and age. 4-6 You will find roughly that much in a meal containing ~ 20-. 30 grams of complete protein found in:

  • 3-4 ounces of meat
  • 3-5 eggs
  • 1-2 cups of Greek yogurt or cottage cheese

Bottom line: Leucine increases muscle protein synthesis, but only up to a point.

Reason # 3: BCAAs don't go straight to your muscles from your mouth.

They first need to find their way through your intestines and into your bloodstream. (And many don't.)

Amino acids compete with each other to get into small doors (called transporters) and into the bloodstream. And they can only use the doors that are specific to their amino acid type. When you flood your GI tract with individual amino acids from a BCAA supplement, the doors reserved for individual amino acids are secured. Instead of your bloodstream, they end up in your toilet.

And those that get into the bloodstream? They still have to find their way into your muscles. (Again many don't.)

This is because leucine can only get into a muscle cell when another amino acid (called glutamine) is leaving the muscle at the same time. So if you have a ton of leucine – and not enough glutamine – leucine either can't get into the muscle cell at all or it happens very slowly.

Conclusion: Leucine needs glutamine to get into muscle cells effectively.

What's Best: BCAAs vs. Whey Protein vs. EAAs vs. Food

Let's start with the truth, straight from Dr. Phillips' emailed me when I told him about this story: "BCAAs are a waste of money … kind of sums up my position."

Here's why:

If you want to supplement, spend your money on essential amino acids (EAAs). You need all of the EAAs to build muscle, not just leucine.

However, EAA supplements are also unnecessary for most people. And they may not be better than … food. The truth is that we don't fully understand the complexities of the interactions between amino acids and other nutrients in the body. It is likely that the ratio of amino acids is more important than the absolute amount of an amino acid or nutrient.

Fortunately, we've evolved to eat whole foods that are likely (of course) in the proportions we need to function well.

In other words, the best “supplement” may be the one you slice with a knife, spear with a fork, and mash between your molars before swallowing.

The main source of amino acids

Yogurt, chicken, rice combined with beans, and other high-protein foods contain all of the amino acids that most people need to build muscle. And they cost less than supplements.

The “only eat real food” approach works for you if:

✓ You are ready, ready, and able to eat high protein foods throughout the day. The data show that muscle growth is maximized by a daily protein intake of 1.6 to 2.2 grams / kilogram (g / kg) body weight. Try to distribute protein throughout the day, with an intake of around 0.4-0.6 g / kg per meal (assuming you eat around 3-4 meals a day). Use our Macro Calculator to get specific protein recommendations based on your gender, age and height.

✓ You are younger than 65 years. When you are younger, less protein is needed to stimulate protein synthesis.

The second largest source of amino acids

Let's say consuming 1-2 servings of protein per meal sounds unlikely. In this case:

Whey protein is your next best option.

As the table below shows, whey has the most leucines and EAAs per scoop when compared to other protein powders

(Read “How To Choose The Best Protein Powder” to understand how these options stack.)

Whey protein is a great option for:

✓ People who don't really like high protein foods. If you're not sure if this describes you, write down what you've eaten in the past few days. Then check how many palm-sized servings of protein you are consuming per meal. If you're not getting 1-2 palms of protein per meal, whey can save the day.

✓ You are trying to lose weight – and you are hungry. You might want to mix up a simple whey protein shake on a regular basis to stop the growl – for relatively few calories.

✓ You are 65 years of age or older. The protein requirement increases with age. At the same time, some older people either feel less hungry or have trouble chewing and digesting certain protein foods. All of this makes it harder to get enough protein from food alone.

✓ You are trying to build muscle while you are losing fat. When people gain muscle mass (including muscle), they usually take some fat with them. Conversely, when they lose fat, they also lose muscle.

(Nobody ever said life was fair.)

But you might be able to minimize your muscle loss by eating more protein while cutting calories, research finds

Compared to a steak, whey protein is relatively low in calories, which makes it easier to increase your protein consumption without increasing your caloric intake as well.

So if you're older or want to increase protein consumption in a simple, low-calorie way, whey is a good source of protein to add to the list.

The # 3 source of amino acids

For the vast majority of people, either whole foods or whey protein provides everything they need.

But EAAs might be a good option if:

✓ You are an athlete trying to lose fat for a competition. Whey protein is not high in calories. In those rare situations where every single calorie counts, it might make sense to use EAAs instead, which provide your muscles with the few building blocks for very few calories.

✓ You cannot tolerate protein powders. Some people have trouble digesting whey and other protein powders. Or they could be allergic to dairy products. In these cases, EAAs might be a better option.

✓ You have nothing against the taste of EAAs. Fair warning: you are bitter.

When should you consume protein? Before, during or after training?

You may have heard that you should consume protein right after your workout to take advantage of what is known as the "anabolic window".

However, this is a misinterpretation of the research.

Yes, exercise makes muscles more sensitive to protein synthesis. In other words, the anabolic window is real. But this window remains open for a long time. If you have meals within two to four hours of your workout, you are good at it.

And most people, unless they fast, will eat within four hours of exercising.

Conclusion: BCAAs are (usually) not worth it.

Even after reading this, you may still want to try BCAAs. Or you have a customer who wants to experiment with them.

That's okay!

The best way to find out if something is working for you or not is this: Conduct an experiment.

How to experiment with BCAAs when you really, really want to try them.

Before you begin, decide on a few metrics that you want to track. You could measure:

  • Appetite on a scale of 1 to 10 before and after meals.
  • Weight or circumference measurements
  • Performance in the gym

Write down your baseline (s).

Then you start taking BCAAs.

Check back in after a couple of weeks. How do you feel? What progress are you making Does the supplement work? Did you see any difference

If so, keep doing what works.

If not, this is helpful information that can save you money.


Click here to view the resources referenced in this article.

1. Plotkin DL, Delcastillo K, Van Every DW, Tipton KD, Aragon AA, Schönfeld BJ. Isolated Leucine and Branched Chain Amino Acids Supplement for Muscle Strength and Hypertrophy Improvement: A Narrative Review. Int J Sport Nutr Exerc Metab. 2021 March 18; 1-10.

2. Drummond MJ, Rasmussen BB. Nutrients enriched with leucine and the regulation of rapamycin signal and protein synthesis of human skeletal muscle in mammals. Curr Opin Clin Nutr Metab Care. 2008 May; 11 (3): 222-6.

3. Churchward-Venne TA, Burd NA, Mitchell CJ, West DWD, Philp A., Marcotte GR, et al. Supplementing a suboptimal protein dose with leucine or essential amino acids: Effects on myofibrillary protein synthesis at rest and after resistance training in men. J Physiol. 2012, June 1; 590 (11): 2751-65.

4. Phillips SM. The influence of protein quality on promoting changes in muscle mass caused by resistance exercise. Nutrition & Metabolism (Internet). 2106, September 29; 13 (64). Available at:

5.Available at:

6. Moore DR. Maximizing Post-Exercise Anabolism: The Case for Relative Protein Intake. Front Nutr. 2019, September 10; 6: 147.

7. Fernstrom JD. Diet-related changes in plasma amino acid pattern: effects on the absorption of large neutral amino acids in the brain and on serotonin synthesis in the brain. J Neural Transm Suppl. 1979; (15): 55-67.

8. Gorissen SHM, Crombag JJR, Senden JMG, Waterval WAH, Bierau J, Verdijk LB, et al. Protein content and amino acid composition of commercially available vegetable protein isolates. Amino acids. 2018 Dec; 50 (12): 1685-95.

9. Longland ™, Oikawa SY, Mitchell CJ, Devries MC, Phillips SM. A higher value compared to a lower dietary protein during an energy deficit combined with vigorous exercise promotes greater muscle mass gains and greater fat mass loss: a randomized study. At J Clin Nutr. 2016 Mar; 103 (3): 738-46.

If you are or want to be a trainer …

Learning how to coach clients, patients, friends, or family members through healthy eating and lifestyle changes – in ways that are tailored to their unique bodies, preferences, and circumstances – is both an art and a science.

If you want to learn more about both, consider the following Precision Nutrition Level 1 certification. The next group will start shortly.

Leave a Reply