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The Controversy around BCAAs
A colleague recently contacted me regarding a Reddit thread about branched chain amino acids.
He said the information on the thread indicated there was a study that showed that branched-chain amino acids were ineffective as a supplement. Of course, he was wondering if I had an opinion, or if I had read the study.
These claims initially took me by surprise as branched chain amino acids are a staple in the
supplement regimen of many athletes, fitness enthusiasts, and health experts. The Reddit thread
highlighted a recently published clinical study by Kevin D. Tipton et. al., and the thread
surmised that BCAA’s are ineffective as a supplement. Is this new study contradicting years of
research and data?
From a personal standpoint, I not only use branched-chain amino acids, but I also recommend
them to many of my patients and athletes who are looking to get leaner and more healthy.
Why? For a number of reasons.
As I previously mentioned, branched chain amino acids are well studied in the scientific
literature where the trials indicate BCAA’s promote health, fitness, and athletic benefits. These
numerous benefits include:
- Increasing lean muscle mass
- Decreasing delayed onset muscle soreness (DOMS)
- Promoting leanness
- Decreasing perceived fatigue when performing high intensity exercise
- Improving the natural metabolism of glycogen in your system
- Increasing rate of contraction of isometric strength
So, then what did the study by Tipton say that has led many to conclude that BCAA’s are
ineffective? In June 2017, Frontiers of Physiology published the study in question: “Branched Chain Amino Acid Ingestion Stimulates Muscle Myofibrillar Protein Synthesis Following Resistance Exercise in Humans”.
Recent BCAA Studies
In the study, researchers evaluated 11 men averaging 20 years of age. Each had over 1 year of
experience performing resistance training on their legs at least twice a week. Suffice it to say that
the study took great lengths to take into account body type, training regimens, and nutrition in
The study group had a baseline 1RM (one rep maximum) for leg press and leg extension measured. Each participant consumed either 5.6 grams of a BCAA supplement or a placebo after performing resistance exercise in one leg. Researchers then measured how much muscle protein synthesis (MPS) resulted over a period of 4 hours after ingestion.
How did they settle on using 5.6 grams of BCAA’s?
This study closely aligned itself with a previous clinical trial that Tipton was also involved in. In that particular study, participants consumed 20 grams of whey protein versus placebo following
resistance exercise. In that study, they found that administering 20 grams of whey protein following resistance exercise increased muscle protein synthesis 37% more than placebo. That said, how does this affect the branch chain amino acid study?
5.6 grams of BCAA’s is actually the same amount of naturally occurring BCAA’s found in the 20 grams of whey protein the Tipton group previously evaluated. Technically they extrapolated that the same amount of BCAA’s were consumed post-workout in each study.
What did the study find and how did it compare to the previous trial?
Tipton and his colleagues found that in the men who completed the study (10), taking branched-chain amino acids following resistance exercise produced a 22% increase in muscle protein synthesis compared to placebo. The study demonstrated that taking BCAA’s following resistance exercise did improve muscle protein synthesis and mTORC1 signaling.
Let’s try and put this into perspective.
Tipton did not conclude that BCAA’s were ineffective. That is NOT what the authors stated. BCAA’s were effective at increasing muscle protein synthesis. In their study, they concluded “ingesting BCAAs alone increases the post-exercise stimulation of myofibrillar-MPS and phosphorylation status mTORC1 signaling.” However, they concluded that taking whey protein post-workout was more effective than taking BCAA’s.
Is this groundbreaking news? No.
Is this consistent with what other studies have shown? Yes, indeed it is. Protein supplementation
following resistance training is superior to post workout BCAA consumption from a building
muscle perspective. So hands down, take a high quality protein supplement following your
But the story doesn’t end there. We know BCAA’s work. But are BCAA’s worth it? Should we take BCAA’s if whey protein is seemingly better?
Are BCAAs Worth Taking?
There are a number of factors that stimulate muscle anabolism. These factors work by switching
on the mTOR gene. This leads to the formation of new proteins within the muscle, a process
called muscle protein synthesis. Resistance exercise is well demonstrated to switch on mTOR
associated processes that lead to muscle protein synthesis.5
Resistance exercise AND post-workout protein supplementation combined, are much more
effective than either of them alone. They have excellent muscle synthesis synergy.
Is there anything we can do to further amplify this effect? Do BCAA’s have a role? Should you
take protein before your workout as well, or do BCAA’s offer advantages?
The Benefits of BCAA’s Not Seen In Protein
We know that pre-exercise supplementation with both branched-chain amino acids and protein
produce mTOR signaling and p70 S6 kinase (part of the muscle protein synthesis cascade). I am
not aware of a specific study that compared and evaluated which one is better.
However, pre-workout BCAA supplementation has several significant benefits to the muscle
building process that pre-workout protein supplementation does not have.
Studies show that BCAA supplementation before and after resistance exercise significantly
decreases delayed onset muscle soreness (DOMS), decreases exercise induced muscle damage,
and lessens the decrease in exercise performance that DOMS produces.6,7
That said, BCAA supplementation before a workout decreases DOMS and exercise induced
muscle damage much more than when it is taken post-workout.8
The muscle is made up of about 35% branched chain amino acids. Exercise produces a
breakdown (catabolism) of these BCAA’s in the muscle. Muscle breakdown is regulated by the branched-chain α-keto acid dehydrogenase (BCKDH) complex.
Exercise activates the muscle BCKDH complex, resulting in increased BCAA catabolism and
muscle damage. Supplementation with branched chain amino acids prior to exercise lessens this
In addition to the benefits of taking BCAA’s prior to a workout, when they are taken during a
workout, there is further activation of muscle mTOR in the post-workout recovery period. Moreover, taking BCAA both before and during a workout turns on muscle protein synthesis. This can further benefit the effects of post-workout protein supplementation.10
Unfortunately, protein and leucine supplementation have been shown to not decrease delayed onset muscle soreness (DOMS) or exercised induced muscle damage. Decreasing DOMS and decreasing exercise induced muscle damage are important strategies to implement in a muscle building program.11
Branched chain amino acids have further effects on the muscle building process. BCAA
supplementation helps maintain the insulin dependent anabolic state, and it specifically helps maintain mass, and increase strength during a hypocaloric diet. This is critical to those in a cutting phase prior to a bodybuilding performance.12,13
Besides the muscle building and strength benefits that branched-chain amino acids have, they
produce a benefit in athletic performance, athletic recovery, fitness, and improved overall health.
Endurance athletes including competing in running, cycling, and triathlon perform much better
when they are taking a branched chain amino acid supplement.
In a review of 14 studies that evaluated this, Ortiz-Moncada et. al. found that BCAA supplementation decreased endurance athletes muscle damage, perceived exertion, soreness, and central fatigue. It also improved the athletes anabolic signaling, recovery and immune response.14
Though BCAA’s do not specifically cause fat loss, they do increase fat oxidation. Studies show
that people who take an adequate daily dosage of BCAA’s tend to have less body fat, a better
body composition and more lean muscle.15
Further evidence suggests that BCAA supplementation is useful in improving glucose utilization,
decreasing insulin resistance, and improving immune function. Scientists have also found that
they help to promote the formation of new cellular mitochondria.16
Recommendations For Effective Use of BCAAs
Is there a consensus on the right dosage for BCAA’s?
Most studies have evaluated the efficacy of branched chain amino acids using a dosage in the 5 – 6 gram range. These studies have found good effects with this dose. However, other studies have demonstrated that the effect from BCAA’s, and specifically leucine, is very dose dependent.17
This means that the higher the dosage, the greater the response.
In 2012 French et.al. showed that a daily dose of 20 grams of BCAA had a significantly greater effect in promoting protein synthesis and decreasing muscle breakdown than smaller doses. They also theorized that the lower muscle protein synthesis seen in other studies was directly related to under dosing.18
From a physician’s perspective, and as an advisor to professional athletes and trainers, I believe that BCAA’s are important to include in a supplement plan.
- Studies demonstrate that a daily intake in the range of 14 – 20 grams of BCAA a day is ideal for health and athletic benefits.
- A 2:1:1 ratio seems to be the ideal split of BCAAs for optimal supplementation.
- High performing supplements, such as BCAA VMINO, have 6 grams of leucine, 3 grams of isoleucine and 3 grams of valine in each dose to make the perfect 2:1:1 ratio.
I recommend that people take it twice a day. For our athletes, I recommend that one of the doses they take occurs before an exercise session.
Try an adequate dosed BCAA supplement before your workouts. You will see enhanced muscle building, improved recovery, and a noticeable decrease in your delayed onset muscle soreness. That is always nice the day after leg day.
Try an adequate dosed BCAA supplement before your workouts. You will see enhanced muscle
building, improved recovery, and a noticeable decrease in your delayed onset muscle soreness.
That is always nice the day after leg day.
- BCAA’s improve muscle protein synthesis and mTORC1 signaling
- Consuming whey protein post-workout is more effective than consuming BCAA’s
- Timing and Dosage are crucial for BCAA’s
- BCAA’s offer many benefits that are not seen with whey protein
- Consume potent BCAA VMINO to improve muscle building, improve recovery, and decrease muscle soreness