Do Amino Acids Build Bigger Muscles?
Amino acids enhance workout performance, promote recovery, and help build muscle. But do we need to buy supplements to keep on hand during workouts? Let’s take a look.
Brock Armstrong
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Do Amino Acids Build Bigger Muscles?
Let’s start with the basics. The most common muscle-building supplement there is can be found right in your fridge. It’s called protein.
When you eat protein, your body breaks the protein down into amino acids. Those amino acids are then used to repair and grow new muscle fibers. When you consume an adequate amount of protein, your body will experience something called a positive balance of nitrogen.
Nitrogen balance is a measure of protein metabolism. That may sound complicated, but it simply means that if the intake of nitrogen into your body is greater than the loss of nitrogen from your body, there is an increase in the total body pool of protein. This positive balance signals your body to get itself into an anabolic, or muscle-building, state.
Here’s an interesting aside: Periods of growth in children, hypothyroidism, tissue repair, and pregnancy are also associated with a positive nitrogen balance.
People who don’t have access to sufficient amounts of protein can experience muscle atrophy and muscle wasting. The US Recommended Daily Allowance (RDA) for protein is 0.36 grams per pound. You’ve probably heard reports saying that Americans eat far more protein than required. But, as my fellow Quick and Dirty Tipper, the Nutrition Diva, pointed out in an article, that isn’t exactly true.
Most Americans are not tearing down muscle under a barbell regularly. But for an active person who works out, a protein intake of approximately 0.45 grams per pound of body weight is adequate.
But before the higher number I just gave gets you thinking that more protein must be better, keep in mind that many studies have found that protein intake above 1.2 grams per pound of bodyweight provided no additional muscle-building benefits. In fact, in extreme cases, excess protein consumption could increase the risk of dehydration and kidney damage.
So yes, we need to consume adequate protein to build muscle, but don’t go overboard. Researchers recently measured the effects of protein on muscle synthesis by feeding people steaks and then measured the rate at which their bodies built new muscle tissue after the meal. They found that muscle synthesis went up by 50% after eating some beef. But 4 ounces of beef worked just as well as 12 ounces.
Amino Acid Supplements
Now that we’ve sorted out how much protein we need, let’s look at amino acids supplements. Think of these supplements as the building blocks of protein. In general, when you purchase them, there are two types: branch chain amino acids (BCAAs) and essential amino acids (EAAs). Let’s explore what each does.
BCAAs
BCAAs have been used by bodybuilders and other strength-based athletes since the 1980s. They contain three amino acids: leucine, isoleucine, and valine. These are known to help your muscles repair faster and encourage recovery after a tough workout. If you ask around, especially at the gym, you’ll find they’re pretty darn popular. But are they really necessary?
The short answer is probably not. Unless a person has a very restricted diet, most people don’t get much benefit from taking BCAAs.
Yes, leucine, isoleucine, and valine are the three main amino acids your body uses to repair muscle, and after a tough workout, your muscles need repair. But these amino acids will repair tissue whether they are from a meal or from a canister with the words Max, Power or Mega printed on it.
EAAs
EAAs are sometimes called the “indispensable amino acids” because they cannot be synthesized by your body, which means they must be eaten. The nine amino acids humans cannot synthesize are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine.
What makes them different? Well, EAAs are vital for muscle tissue development and cell repair when the muscles are recovering.
You can think of it like this: BCAAs are the switch that turns on muscle building, and EAAs are the actual fuel that makes muscles grow. BCAAs prime your body for muscle growth, but you need the other building blocks to build actual tissue.
Building Muscle Requires Working Out
This is an important point—taking amino acids or even simply eating a lot of protein-rich foods will not help you grow muscle on their own. Sure, you need adequate levels of protein in your diet to maintain muscle mass, but more is not going to turn you into an Avenger.
Research has shown that for males in their twenties, muscle synthesis peaks at an intake of about 20 grams of protein per meal. But as we get older, it takes a little more protein to hit that peak. They need to get somewhere closer to 30 grams in a single meal. For your reference, that’s about what you will get from four ounces of cooked chicken, beef, or pork, or about six ounces of tofu.
An article published in The Physician and Sportsmedicine in 2009 stated there is significant evidence that intense training increases the requirement for dietary protein. But notice they used the words “intense exercise.” That is what I want to stress. Popping a bunch of protein or amino acid supplements is only beneficial if your exercise level is exceeding your dietary intake. And let’s be honest, most of us are not exercising that intensely most days of the week.
Do amino acid supplements work?
Simply put, yes. There is solid evidence that BCAAs increase protein synthesis and enhance recovery after a hard workout. But—and this is a big but—if you have been eating complete proteins (which I will get to later) before or after a workout, then you already have plenty of everything you need on board.
In that case, just like the amount of protein your body needs, taking more amino acids in supplemental form is unnecessary. All the goodness that your muscles need is in that steak, chicken, egg, tofu, or fish that you ate for lunch or dinner last night.
In fact, protein researcher Stuart Phillips, Ph.D., of McMaster University told Men’s Health magazine, “Bottom line: If you’re taking in adequate protein, then BCAAs are a complete waste of money.”
When You Work Out Before Breakfast
Fasted workouts, generally done before you eat breakfast, are quite popular these days. The problem is that if you crush a killer workout with zero food in your belly, your muscles won’t have the right amino acids to rebuild. This is especially a concern if you also aren’t planning to eat soon after the workout. This is where BCAAs can be helpful.
Taking an appropriate dose of amino acids right after your hard workout can indeed give your muscles the building blocks they need for repair. Then again, eating an omelet shortly after that same workout would accomplish the same thing.
Best Sources of Amino Acids
Protein-rich foods are not all created equal. Some foods are said to provide a complete protein, while others are known to be incomplete. The difference between the two comes down to which amino acids are present in each food.
When a food contains all the essential amino acids, it is said to be a complete protein. Most animal proteins are considered complete proteins. But vegetable sources of protein, (beans, seeds, and grains) are often missing some of the essential amino acids and are considered incomplete proteins.
Amino acids are found in a number of healthy, protein-rich foods including beef, salmon, egg yolks, cheese, quinoa, pumpkin seeds, and many nuts.
In her article Protein Density: How To Get More Protein for Fewer Calories, the Nutrition Diva points out that protein density does not take into account protein quality. Because they contain a more optimal distribution of essential amino acids, animal proteins have a higher biological value than plant-based proteins. So there you go, unless your lifestyle has you avoiding animal protein, you are best off avoiding the plant-based protein choices.
Should You Take Amino Acids?
Increasing your dietary protein (up to a point), or even supplementing your diet with amino acids, can help you improve your body composition, but only if you fit into one of these two criteria:
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You are not currently eating enough protein.
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You are exercising at a high enough level to exceed your current level of protein intake.
For more muscle building info, recovery tips, and to join the supplemental conversation, head over to Facebook.com/GetFitGuy, twitter.com/getfitguy or BrockArmstrong.com.
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About the Author
Brock Armstrong was the host of the Get-Fit Guy podcast between 2017 and 2021. He is a certified AFLCA Group Fitness Leader with a designation in Portable Equipment, NCCP and CAC Triathlon Coach, and a TnT certified run coach. He is also on the board of advisors for the Primal Health Coach Institute and a guest faculty member of the Human Potential Institute.