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
6-minute read
Episode #437

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.

Popping a bunch of protein or amino acid supplements is only beneficial if your exercise level is exceeding your dietary intake.

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. 


About the Author

Brock Armstrong

Brock Armstrong 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. Do you have a fitness question? Leave a message on the Get-Fit Guy listener line. Your question could be featured on the show.