What Are Branched Chain Amino Acids and Do They Help Muscle Growth and Recovery?
I remember back in the day, you’d see all the bodybuilders at the gym sipping on purple water from those clear shaker bottles. They were drinking water spiked with BCAAs, or branched chain amino acids, the idea being the BCAAs provide your body a steady drip of amino acids to maximize muscle hypertrophy and stay anabolic all day long. Heck, even I sipped the purple water when I was trying to gain mass. In more recent years, BCAAs have fallen out of favor, or at least become less “vital” a supplement for people interested in gaining muscle.
However, branched chain amino acids are still among the most crucial amino acids for human health, metabolism, immunity, and hypertrophy. Without adequate intake of the BCAAs leucine, isoleucine, and valine, we won’t be able to activate all the metabolic pathways we need to generate energy and utilize macronutrients. Our intestinal health suffers. Our immune system grows sluggish. And, most importantly, without BCAAs we won’t be able to trigger the mTOR pathway necessary for muscle building and repair.
That’s what everyone cares about when they talk about BCAA supplementation: muscle growth and recovery. That’s why the purple water was so common. So, what’s the deal? Do BCAAs work for muscle growth and recovery?
Well, we do need BCAAs. We can’t make them—they are essential amino acids, meaning we must obtain them from outside sources rather than manufacture them in-house. We must eat them.
But do we have to sip the purple water? Must we supplement BCAAs?
Let’s find out.
What Are BCAAs Made Of?
When most people talk about BCAAs, they’re talking about leucine. If you had to choose one amino acid for building muscle, it would be leucine. Leucine activates mTOR, or mammalian target of rapamycin, the physiological pathway required for muscle protein synthesis. Simply ingesting leucine has been show to upregulate mTOR and muscle protein synthesis in people. If you pair leucine with some resistance training, the effect is even greater.
Leucine is the amino acid vegans and (often) vegetarians are usually missing, as plant foods contain very little. You can get there if you utilize specially-formulated plant protein powder blends (or eat straight up vital wheat gluten), but if you go with whole plant foods alone you’d be hard pressed to get enough leucine—over 800 calories of peanuts or 3600 calories of wheat bread are required to get just 2.5 grams of leucine.
On the other hand, animal foods are the richest sources. 23 grams of whey protein isolate (92 calories), 142 grams of top round (391 calories), or 142 grams of chicken breast (147 calories) are animal-based ways to get 2.5 grams of leucine. Dairy, eggs, and other animal foods are also great sources. It’s way easier to get enough BCAAs from your diet if you eat meat, and most prolific meat-eaters are going to be getting plenty of BCAAs simply from their diet.
So if you’re reading this, and you’re eating meat, eggs, dairy, and other animal foods on a regular basis like most readers and visitors to this site, you’re probably getting enough BCAAs to take care of your requirements. You probably don’t need to supplement with additional BCAAs.
However, there are some people who should definitely take BCAAs.
When Does It Make Sense to Take BCAAs?
There are a few different situations where supplementing with BCAAs can help you achieve your goals and recover more quickly:
- You’re vegan.
- You train fasted.
- You’re on a calorie-restricted diet.
- You’re recovering from an injury, illness, or bedrest.
- You want to get back into competition or training more quickly.
Sure, you could live off soy protein powder. Sure, you could sprinkle pea protein powder into everything you eat and drink. But if you want to eat a more whole foods-based vegan or vegetarian diet, adding a serving or two of BCAAs directly will give you more leeway. I still wouldn’t advise this, but if you’re dead-set on it, include some BCAAs.
You train fasted.
If you’re doing fasted weight training, it would be prudent to take 10-15 grams of BCAAs before the training session. For one, they are muscle-sparing, especially during intense resistance training. The last thing you’d want during a fasted workout is for your body to start breaking down muscle to create glucose. Taking them before a fasted workout would be more effective than after, though if you were planning on continuing the fast post-workout, more doses on the hour should prevent muscle breakdown until you’re able to eat some real food.
And two, BCAAs taken during and after a strength training session augment the normal mTOR boost in muscle tissue resulting from training alone.
BCAAs will turn off the autophagy induced by fasting, but if you’re trying to build muscle, by necessity you must halt autophagy. Plus, it’s the end of the fast so you were already going to turn it off anyway..
You’re on a calorie-restricted diet.
The worst part about a diet is the lean mass you can lose. It’s not “weight” we want to lose, it’s fat. We’d prefer to maintain or even gain lean mass, and BCAAs can help.
Young adults on a calorie restricted diet were split into one of two groups: a BCAA group or a carb group. Both groups lifted weights throughout the study. The group who took BCAAs lost fat mass and retained lean mass. The group who took carbs lost weight but not fat mass—only lean mass. Thus, BCAAs didn’t promote “weight loss” but they did promote fat loss. Carbs promoted “weight loss” but not fat loss.
You’re recovering from an injury, illness, or bedrest.
Recovering from injuries, surgeries, bedrest, or illness requires a lot of amino acids, especially the BCAAs, which help make the necessary repairs. You haven’t been exercising. You haven’t been eating right. Your tissues (not just your muscles) have been atrophying. A lot has gone wrong, and you need to rebuild. That takes extra amino acids, and that’s where supplementing with BCAAs has been shown to help.
In stroke patients, adding BCAAs to their breakfast makes lifting weights later in the day more anabolic, leading to improved body composition.
Another study in stroke patients had similar results. In that one, Both groups ate the same food provided by the hospital, both were calorie-matched and of similar baseline status, only the interventional group got a BCAA supplement. What’s remarkable is that the BCAA dosage was relatively modest—just 1.2 grams of “extra” leucine per day. And it was still enough to increase muscle strength and muscle mass.
How about patients with sarcopenia—muscle wasting? Giving a BCAA supplement (plus vitamin D and exercise) to sarcopenic older adults staying in a hospital setting improved their strength gains; those who did not receive BCAAs (but still exercised) had impaired gains.
After surgery, which is pretty much a controlled wounding, protein intake is probably the most crucial aspect of the patient’s nutrition and subsequent recovery. Many doctors recommend that surgical patients take whey protein isolate—the richest source of BCAAs in the diet—for a couple days after a procedure.
You want to get back into competition or training more quickly.
If delayed onset muscle soreness (DOMS) is holding you back from training, BCAAs can be very helpful. A recent meta-analysis concluded that a “large decrease in DOMS occurs following BCAA supplementation after exercise compared to a placebo supplement.”
Should Healthy People Supplement with BCAAs?
What about healthy people who eat three meals a day, lift weights in a fed state, and just want a boost to their muscle growth? Can BCAA supplements help them?
They can’t hurt. BCAAs are useful. Your body will use them if you provide them. They’re pretty helpful for reducing DOMS (delayed onset muscle soreness) and they do increase mTOR, which is helpful for muscle protein synthesis. They just don’t seem to be essential in the context of adequate animal protein.
For example, in one recent study, BCAAs moderately reduced post-workout muscle soreness following eccentric exercise training (lowering the weight), but the effects on force production and performance were negligible as long as the subjects ate enough protein—1.2 grams of protein per kilogram of bodyweight, to be exact.
Besides, you could just take whey isolate. Whey protein isolate will accomplish pretty much the same thing as BCAAs because it’s a rich source of BCAAs, plus other essential amino acids. 25 grams of whey protein isolate, remember, gets you the 2.5 grams of leucine that’s proven to be so helpful for muscle growth. I’ve spoken at length about the impressive benefits of whey protein in the past for both muscle growth and general health.
To sum up, certain conditions and situations call for extra BCAAs through direct supplementation (or whey isolate), while most healthy people do not need to take them as long as they eat enough dietary protein.
Now let’s hear from you. Do you take BCAAs? What kind of benefits do you see?