Amino acid supplements, especially BCAA supplements, are some of the most popular products on the market, and it’s easy to understand why when you see some of the outlandish claims stated surrounding their usage.
But, the truth is that a lot of what is said about BCAA supplements is overblown. On the one hand, you have those who swear that BCAA supplements are the “hidden secret” to packing on pounds of lean muscle mass.
On the other hand, you have those that state that BCAA supplements are a complete waste of money.
In this article, we’ll help separate fact from fiction surrounding the use of BCAA supplements as well as discuss:
- What are BCAAs?
- When to take BCAAs?
- Should I take BCAAs every day?
What are BCAA?
BCAA stands for branched-chain amino acids and consists of:
They are a special subgroup of the essential amino acids.
Essential amino acids are amino acids (building blocks of protein) that our bodies cannot produce.
Therefore, they must be obtained through the diet, or if you’re not getting sufficient levels of the essential amino acids from the diet (including the three BCAA), then supplementing with them becomes a priority (at least if you want to maintain or build muscle, that is).
Why Are BCAA Supplements Popular?
The three BCAA initially jumped on researchers’ radar when it was discovered that they are metabolized differently in the body than other amino acids.
More specifically, the three BCAA bypass metabolism in the liver and are oxidized in the muscles.
Furthermore, researchers also noted that the BCAA, leucine, in particular, are capable of stimulating the mTOR pathway, which is the biological pathway that stimulates muscle protein synthesis and subsequently fuels muscle growth.
And, when you realize that the BCAAs account for approximately 35% of muscle mass, you can begin to understand why they’re so important.
Now, the reason BCAA supplements gained popularity largely stems from industry-funded research showing that consuming BCAAs led to significant muscle growth. [1,2]
However, when you drill down into the actual research, you see that the subjects weren’t consuming adequate amounts of protein.
Now, while those some studies (and supplement companies) have exaggerated the benefits and properties of BCAAs, that doesn’t mean they are without merit.
As we mentioned, your body must get these to synthesize protein. As such, if you’re someone who doesn’t consume enough protein each day, or eats a mostly plant-based or vegan diet, you may be low in the BCAA. Therefore, consuming BCAA might confer additional benefits.
Additionally, various studies have noted that each of the BCAA does possess some unique properties, such as:
Leucine is an incredibly potent activator of mTOR and has been shown to stimulate protein synthesis directly. It also exerts some anti-catabolic properties, meaning it helps prevent the breakdown of muscle protein in the body. [3,4]
In addition to stimulating mTOR (albeit to a lesser degree than leucine), Isoleucine has been shown to enhance glucose uptake into cells in addition to improving glucose metabolism. 
Valine hasn’t been shown to offer many muscle-building properties (outside of its role as an essential amino), but it has shown to compete with tryptophan (another essential amino acid) for uptake into the brain.
Why is this important?
Tryptophan is the amino acid used to synthesize serotonin; a neurotransmitter noted to play a role in the onset of fatigue during exercise. By preventing tryptophan from being taken up, valine can help reduce the production of serotonin, and thereby the onset of fatigue, allowing you to train for longer — completing more work and burning more calories.
There are a few benefits of supplementing BCAA as noted in the research, included:
- Increased fat oxidation during exercise
- Reduced fatigue
- Decreased muscle soreness following training
- Prevents muscle breakdown
Now, with that said, let’s discuss some different dosing scenarios and whether or not using a BCAA supplement makes sense.
BCAA Before Bed
One of the oldest myths circulating the muscle-building realm is that you need to have protein before bed to prevent yourself from going catabolic.
This stems from the fact that when we sleep, our bodies enter into a ‘fasted state’ where plasma insulin levels drop to baseline, and during this time the body will rely on stored body fat for energy.
Furthermore, protein breakdown also occurs when insulin levels are low. 
As you might imagine, if you’re keen on building muscle as fast as possible, the thought of protein breakdown sounds pretty frightening.
Since the BCAAs help prevents muscle breakdown, it makes sense (in theory) that you should have a serving before bed.
However, the body isn’t quite that simple.
Our bodies are in a constant state of building and breaking down protein as well as burning and storing fat.
What we’re more concerned with is the net result protein synthesis vs. protein breakdown. By that, we mean that so long as the overarching result is protein synthesis outpacing protein breakdown, you’ll gain muscle.
The best way to ensure that is to consume enough protein each day. If you’re already doing that, then you don’t need to worry about consuming BCAA before bed. However, if you aren’t consuming adequate dietary protein, you may want to consider supplementing with BCAA.
BCAA During Workout
Endurance exercise places significant demands on energy reserves as well as stress on the muscles. Furthermore, prolonged physical activity (as well as fasted training) has also been noted to lead to significant muscle protein breakdown.
In line with this, sports scientists have observed significant reductions in plasma levels of BCAA which are associated with muscle loss.
Supplementing with BCAA may help prevent muscle loss during exercise by providing muscle cells with a readily accessible form of energy to use, so that muscle tissue is not broken down to meet the energy demands of the body.
Best Time to Take BCAA for Weight Loss
When dieting, you’re consuming fewer calories than your body requires to maintain its current weight. As such, it is at a heightened risk for protein breakdown.
This is why most nutrition recommendations from physique coaches and trainers suggest upping your protein intake above the typically recommended 1 gram of protein per pound of body weight per day.
Since calories are at a premium when dieting, and that you may have trouble consuming enough protein to prevent muscle loss, supplementing with BCAA makes sense to help stave off any potential protein breakdown, and thereby muscle loss.
Should I Take BCAA Every day?
As we’ve stated a few times throughout this article, BCAA can be helpful in a few scenarios, particularly if you have trouble consuming enough dietary protein abundant in BCAA or engage in extreme endurance training.
If not, then there is no need to take BCAA every day.
All that being said, many individuals do not consume enough water each day or electrolytes (which are needed for optimal performance). If by drinking BCAA, you’re able to increase your water and/or electrolyte intake, then feel free to use them daily. They certainly won’t hinder your results and may help them.
- Howatson G, Hoad M, Goodall S, Tallent J, Bell PG, French DN; “Exercise-induced muscle damage is reduced in resistance-trained males by branched-chain amino acids: a randomized, double-blind, placebo-controlled study”; Journal of the International Society of Sports Nutrition; 9:20; 2012
- Stoppani, Jim, et al.; “Consuming a supplement containing branched-chain amino acids during a resistance-training program increases lean mass, muscle strength, and fat loss“; Journal of the International Society of Sports Nutrition; 2009; 6(Suppl 1): P1
- Kimball, S. R., & Jefferson, L. S. (2006). Signaling pathways and molecular mechanisms through which branched-chain amino acids mediate translational control of protein synthesis. The Journal of Nutrition, 136(1 Suppl), 227S-31S.
- Baticci, F., & Bozzetti, F. (1990). Anti-catabolic properties of branched chain amino-acids in post-operative patients. A prospective study. Clinical Nutrition (Edinburgh, Scotland), 9(5), 246–252.
- Cooper GM. The Cell: A Molecular Approach. 2nd edition. Sunderland (MA): Sinauer Associates; 2000. Protein Degradation. Available from: https://www.ncbi.nlm.nih.gov/books/NBK9957/