We all know there’s no cheating when it comes to getting stronger or faster—that comes from training and hard work. But that doesn’t stop us from looking for an edge and wondering if special supplements could light a fire under our feet (or at least make us feel like we’re not going to die 10 miles into a long run).
That’s where BCAAs, or branched-chain amino acids, come in. You’ve probably heard about these at the gym, or maybe in your run club, or maybe you’ve even heard of pro athletes using them. But what are BCAAs, what are BCAA benefits, and should you be taking them?
What Are BCAAs?
First, a quick refresher on amino acids: They are the building blocks of protein, which helps your body build muscle, repair muscle damage, and regulate immune function, among other things. While there are 20 amino acids in total, nine are essential—essential, because your body can’t produce them, but you need them to live. BCAAs are three specific essential amino acids that inhibit muscle protein breakdown and aid in glycogen storage: leucine, isoleucine, and valine.
Because BCAAs are essential, you have to get them from your diet. “Any complete protein will contain all amino acids, and therefore BCAAs,” explains Monica Auslander Moreno, R.D., nutrition consultant at RSP Nutrition and founder of Essence Nutrition. Examples of complete proteins include animal-sourced products such as eggs, meat, poultry, fish, and dairy. “You can also find [BCAAs] in other plant-based protein sources,” she adds, especially peanuts, chickpeas, lentils, quinoa, and whole grains. When grains and legumes are eaten together (think: rice and beans or peanut butter on whole grain bread), they make up a complete protein.
So if you can consume BCAAs pretty easily through your diet, why take supplements? “People take BCAA supplements for a number of reasons, including reducing muscle soreness, increasing power output, increased time to exhaustion, decreased lactate production, and weight loss,” says Kristin Koskinen, R.D.N., of Eat Well Pros.
“What makes BCAAs unique is that they can be oxidized in the muscles for fuel,” explains Angie Asche, R.D., of Eleat Sports Nutrition. “They work to prevent muscle breakdown during exercise, and are beneficial after exercise by stimulating muscle building and promoting recovery.” So when your glycogen stores run low, your body turns to BCAAs for fuel.
These three amino acids make up approximately one-third of muscle protein, adds Koskinen. And “while other amino acids are metabolized in the liver, BCAAs bypass the liver and head directly to muscles located away from the core,” says Asche, which could aid in energy production. Research has even linked BCAA consumption to increased resistance to fatigue, reduced muscle damage, and increased muscle mass.
“Theoretically, BCAAs reduce fatigue during prolonged exercise by preserving glycogen stores,” explains Koskinen. “Remember, BCAAs can act as fuel during exercise and can be delivered more efficiently to muscles. Supplementing with BCAAs and carbohydrates was shown to reduce postrace fatigue in a group of marathoners—although the results only applied to slow runners, not the more elite athletes.”
They may also help you bounce back faster after that track workout. “BCAAs inhibit cortisol, which can cause muscle breakdown, and therefore contribute to faster muscle recovery (and less soreness),” says Auslander. “And leucine in particular is great at stimulating muscle protein synthesis—it acts almost like a command sergeant in lining up other amino acids to together form new muscle tissue.”
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Should You Try Them?
With those kind of benefits, it’s no wonder supplements sound appealing. But the reality is, most people get enough BCAAs from the food they already eat, says Koskinen. “People who aren’t eating enough protein or carbs may benefit, but it’s much more effective to make diet corrections than try to supplement your way to peak performance,” she adds.
That said, people with GI issues or those who have a hard time eating anything before early morning workouts could benefit. “Consuming a serving of a BCAA 2:1:1 supplement (2 grams leucine to 1 gram valine and 1 gram isoleucine) 15 minutes before a workout or run offers a readily absorbed protein and energy source,” says Koskinen.
How much BCAAs you would need is pretty individualized, says Auslander. “It’s based on weight, gender, and physical activity, type, and time,” she explains, so talking to an R.D. before experimenting would help you figure out what might work for you. But “total amounts of five to 10 grams per day seem to provide the most benefit.”
It’s important to note that supplements aren’t regulated, and even though BCAAs don’t have any known negative side effects, you always have to be very careful about where you buy from, what’s in the supplements, and how much you take (groups like NSF or Informed Choice provide reputable certifications). And while BCAAs might help you feel less fatigued during a workout or sore after a workout, they may not actually improve your performance.
Plus, BCAAs aren’t cheap. “Other less expensive, convenient options may be better suited for providing not only the BCAAs but the other essential amino acids necessary,” says Koskinen. For example: Whey is a complete protein, with all nine essential amino acids. “It’s also quickly digested and absorbed.”
Before you start popping supplement pills or dropping any kind of powder into your water, talk to registered dietitian who has experience working with runners about what’s right for you and your training plan. And remember that nutrients are better absorbed when they come from food, so upping your protein intake via whole, healthy foods should always be your first choice. But if you’re a distance runner and feeling absolutely wiped during and after your long runs, BCAAs might help get rid of some of that fatigue.