Branch Out With BCAAs

BCAAs do more than just build muscle

Written By Jim Stoppani, PhD

Updated March 28, 2024

The branched chain amino acids (BCAAs) are the three most critical amino acids for building muscle. But these three powerful aminos do far more than just grow muscle. In addition to being the most effective amino acids for muscle growth, these bad boys also boost energy levels, delay muscle fatigue, and even aid fat loss.

BCAA Backtalk

The BCAAs include the three essential amino acids – leucine, isoleucine and valine. From a chemical structure standpoint, each of these amino acids has a forked outcropping that looks a lot like a branch. And that's where they get their name from. If they were named for what they do in the body, they would have been called AAAs - for Amazing Amino Acids!

What's makes the BCAAs so special is how the body handles them. Typically, when you ingest amino acids (either as individual amino acids or as whole protein) they first travel to the liver. Here the liver can break them down to use as fuel if it decides the body needs them for energy rather than for building and repairing muscle and other tissues. The BCAAs tend to be spared by the liver and get sent directly to the muscles so that the muscles can decide what to do with them. Unlike the other amino acids, the muscle can use the BCAAs directly for fuel or to build and repair itself. So during workouts, the BCAAs can act as a fuel source, but then when the workout is over, they can build muscle.These are just two reasons why it's so critical to take BCAAs before and after workouts.

Power Source

As I alluded to above, BCAAs are used for fuel by muscle during workouts. And the more intense and the longer the workout, the more BCAAs that will be used for fuel. So you can see how taking a dose of BCAAs before workouts can literally give you more energy during the workout to help you train with more intensity from start to finish. But acting as a direct energy source for muscles is not the only way that BCAAs boost your workout intensity.

BCAAs also work via the brain to delay fatigue. During exercise a metabolite of the amino acid tryptophan, known as 5-hydroxytryptamine (5-HT), signals the brain that the body is fatigued. This leads to a reductipn in muscle strength and endurance. The amino acid tryptophan is responsible for producing 5-HT in the brain, which the BCAAs, namely valine, compete with for entry into the brain. Research has discoveredthat taking BCAAs before workouts lowers the amount of tryptophan that gets into the brain and therefore the levels of 5-HT and fatigue. This is due to the fact that the BCAAs, namely valine, compete with tryptophan for entry into the brain. So taking BCAAs before workouts can also delay fatigue during the workout, further enhancing your intensity, strength and endurance.

This ability of BCAAs to delay fatigue via this brain mechanism, also means that BCAA supplements aren't just beneficial for the body, but the brain as well. By reducing levels of 5-HT in the brain, you reduce mental fatigue, which keeps you sharper mentally. So dosing with some BCAAs later in the day at work will keep you focused.

BCAAs have recently been found to increase a different type of endurance - life span. Researchers from Milan, Italy discovered that mice supplemented with BCAAs in their drinking water had higher amounts of mitochondria in their muscles, higher activity of the longevity gene, SIRT1, and lived 12% longer than those not getting BCAA enriched water. So supplementing with BCAAs daily can keep you going longer in the race we call life.

Bigger, Stronger

The BCAAs gained their popularity with bodybuilders due to their ability to directly increase muscle size. As you likely know, muscle is made of protein. And protein is made up of amino acids strung together like a pearl necklace. So the way that muscle grows is by stringing together amino acids to make more protein. This is known scientifically as muscle protein synthesis. Although the three BCAAs are critical aminos in the "strings" of proteins that make muscle, their role in muscle building is much more than just serving as building blocks.

Research has discovered that the BCAAs, particularly leucine, increase muscle growth by directly stimulating muscle protein synthesis. Leucine literally acts like a key that turns on the process that strings the amino acids together to build muscle protein. Additionally, leucine boosts insulin levels. Insulin is an anabolic hormone that further stimulates protein synthesis, but via a different mechanism than leucine.

Another way that BCAAs work to enhance muscle growth and strength is by boosting levels of growth hormone. Italian researchers found that athletes taking BCAAs for one month had higher levels of growth hormone after workouts. The higher your GH levels after workouts the greater the increases in muscle size and strength you can expect. And yet another hormone that BCAAs influence to promote muscle growth and strength gains is cortisol. However, research shows that athletes taking BCAAs have lower levels of cortisol during exercise. This blunting of cortisol levels works to increase muscle growth because cortisol is a catabolic hormone that interferes with the anabolic hormone, testosterone, and encourages muscle breakdown. And numerous studies have confirmed that athletes taking BCAAs have significantly less muscle breakdown after exercise and better muscle recovery.

So in essence, the BCAAs promote muscle growth and strength through five different mechanisms 1) serving as the building blocks to make muscle protein, 2) directly activating the process that turns on protein synthesis, 3) indirectly activating protein synthesis through insulin, 4) elevating GH levels, and 5) lowering cortisol levels. Now you can understand why it's so important to take BCAAs after every workout. In fact, a study I performed with the Weider Research Group looked at just how critical taking BCAA supplements around workouts is. We reported at the 2009 Annual Meeting of the International Society of Sports Nutrition that trained lifters taking a BCAA supplement around workouts for 8 weeks gained about twice as much muscle muscle and strengh those taking a whey protein shake without additional BCAAs added to it. This study confirms earlier studies also showing increased strength, such as a 2003 Italian study showing that men taking BCAAs for two days increased their grip strength compared to those taking a placebo.

Branch Out for Fat Loss

The BCAAs are not just great building supplements, they also can aid fat loss. One of the first studies to discover this benefit was a 1997 study in competitive wrestlers that found that those who were supplementing with BCAAs while following a low-calorie diet experienced a greater drop in body fat, particularly in the waist, as compared to those taking a placebo. My study also found that the lifters taking BCAAs lost about twice as much body fat as those taking whey protein without added BCAAs. Although its uncertain precisely how the BCAAs aid fat loss, there are some theories.

A study out of Brazil found that leucine supplementation for 6 weeks caused a large drop in body fat. The researchers proposed that the increase in protein synthesis stimulated by leucine increased energy expenditure so much that it helped to burn off body fat. Leucine has also been found to reduce hunger, causing you to eat less while you burn more, which ultimately leads to fat loss. In the most recent study on BCAAs fat loss effects, Japanese researchers discovered that mice given isoleucine while eating a high fat diet gained significantly less fat than mice not getting supplemental isoleucine. This was due to isoleucine's ability to activate special receptors, known as PPAR, that increase fat burning and inhibit fat storage.

BCAA Dosing

Each time you take BCAAs you should go with about 5-10 grams. The most critical time to take them is around workouts. So be sure to add 5-10 grams to your pre and postworkout shakes. Also consider taking a dose of BCAAs first thing upon waking to help stop the muscle breakdown that is turned on during your night of fasting while you sleep. You can also take a 5-10 gram dose of BCAAs at any other time of day to get an energy boost, reduce hunger and aid muscle growth.

BCAAs at ideal doses and ratios of leucine to isoleucine to valine are included in both Pre JYM and Post JYM, as well as my stand-alone JYM BCAAs product.

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