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BCAAs: 5 Reasons Your Body Needs Them

Here’s why branched-chain amino acids (BCAAs) are a key ingredient for any serious gym-goer’s success.

BCAAs: 5 Reasons Your Body Needs Them
Written By Jim Stoppani, PhD
Updated December 22, 2023

Most people have a tough time wrapping their heads around exactly how some tiny little amino acids called BCAAs can have such a significant impact on gains in muscle size and strength, fat-burning and athletic performance. It’s much easier to imagine how a thick steak or chicken breast can be turned into lean mass and even how a couple scoops of protein powder can help damaged muscles repair themselves and grow bigger.

But a relatively small scoop of white amino acid powder? (BCAAs, as you probably know, are present in both Pre JYM and Post JYM along with other effective ingredients, as well as in my stand-alone JYM BCAAs.) How is it even possible that real, noticeable gains can come of that? I’ll tell you how: Because the three branched-chain amino acids (BCAAs for short) – leucine, isoleucine and valine – are different from all the others. I explain right here as I outline the key reasons why BCAAs should be part of your transformation game plan.

REASON #1: BCAAs PROMOTE MUSCLE GAINS

You can’t transform your body without building some muscle, and BCAAs promote muscle growth in several different ways.

First, BCAAs serve as the building blocks of muscle protein. Muscle is made up of protein, and protein is made up of amino acids strung together like a pearl necklace though a process called protein synthesis. But not all amino acids are so intimately involved in this process. When most amino acids are ingested, they’re absorbed by the intestines and shuttled straight to the liver. The liver then decides what to do with them before they go to the rest of the body. If the body needs more energy, the liver will break them down for fuel rather than spare them to repair and build muscle and other tissue. The three BCAAs, on the other hand, tend to be spared by the liver and get direct access to tissues like muscle fibers. The muscle fibers then get to make the decision of what to do with the BCAAs based on their needs. One of these needs could very well be to build muscle fibers up. (I’ll cover another typical need in Reason #3.)

Staying on the topic of protein synthesis, leucine is by far the most valuable of the three BCAAs for building muscle. Much like the ignition of a car starts the engine, leucine turns on the process of muscle protein synthesis. In scientific terms, leucine activates a complex called mTOR, which ramps up protein synthesis, and therefore muscle growth. Research has shown that subjects adding extra leucine to their post-workout protein and carbs experienced significantly greater muscle protein synthesis than those taking only protein and carbs.

Leucine also boosts levels of insulin, an anabolic hormone that may further stimulates protein synthesis in its own, separate from leucine, and decreases muscle protein breakdown. Plus, insulin is critical for driving creatine and carnitine into muscle cells to promote recovery and growth. Immediately following an intense training session is a critical time for increasing insulin levels to promote muscle gains.

Two other important muscle-building hormones are affected by BCAAs: growth hormone (GH) and cortisol. In one study, Italian researchers found that athletes taking BCAAs for one month had higher levels of GH after workouts than those who didn’t take the supplement. The higher your GH levels after workouts, the greater potential you’ll have for increases in muscle size (not to mention strength) as well as fat loss.

Finally, research shows that athletes taking BCAAs have lower levels of cortisol during exercise. This is a good thing, as cortisol is a catabolic hormone that interferes with testosterone and encourages muscle breakdown. Numerous studies have confirmed that athletes taking BCAAs have significantly less muscle breakdown after exercise and better muscle recovery.

REASON #2: BCAAs AID FAT LOSS

We’re not just talking about a muscle-building supplement here; BCAAs, specifically, leucine and isoleucine, can also a play a major role in your get-lean efforts. One of the first studies to highlight this benefit was a 1997 experiment done on competitive wrestlers which found that subjects 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.

Moreover, a study out of Brazil found that six weeks of leucine supplementation 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. These results were apparantly due to isoleucine's ability to activate special receptors, known as PPAR, that increase fat burning and inhibit fat storage. PPAR works to increase the activity of genes that encourage greater fat burning in the body, while at the same decreasing activity of genes that increase fat storage.

REASON #3: BCAAs INCREASE ENERGY AND DELAY FATIGUE

I wrote earlier that BCAAs are used for multiple needs by the muscle fibers. One common need is as an immediate energy source, particularly during intense training sessions. The more intense and the longer the workout, the more BCAAs that will be used for fuel. This is exactly why I include a full 6-gram dose of BCAAs in Pre JYM – because more fuel for the muscles means you’ll be able to train more intensely and for a longer period of time, which is critical for a drastic improvement in body composition.

Valine in particular plays a key role in providing energy for workouts. During exercise, tryptophan is taken up by the brain in large amounts. Tryptophan is converted in the brain to 5-hydroxytryptamine (5-HT), or what you likely know as serotonin. Having higher serotonin during exercise signals the brain that the body is fatigued, w hich leads to a reduction in muscle strength and endurance. Valine, however, competes with tryptophan for entry into the brain and typically wins out. The result? Less tryptophan gets in and converted to serotonin, which allows your muscles to contract with more force for a longer time before getting fatigued.

REASON #4: BCAAs BOOST THE IMMUNE SYSTEM

Few things can derail a physical transformation like getting sick. You know how it goes: You’re making great progress and are humming right along in the gym for a few months, and then, bam, you get sick and miss a week. Then you’re back in the gym for a few weeks, and bam, sick again and missing more precious gym time.

Yes, BCAAs can help, as they’ve been shown to enhance immune function following exercise. Since intense training can take its toll on your immune system (especially when also dropping calories) and increase your chances of getting sick, supplementing with BCAAs is a smart idea to keep from catching a cold or flu and missing time from the gym.

REASON #5: BCAAs MAY ALSO INCREASE LIFE SPAN

In one study out of Milan, Italian researchers discovered that mice who supplemented with BCAAs had higher amounts of mitochondria in their muscles, higher activity of the longevity gene SIRT1 and lived 12% longer than those not getting BCAAs. Although these effects have yet to be confirmed in humans, it sure would be a nice fringe benefit from a supplement already providing numerous other positives.

TAKING YOUR BCAAs

Supplementing properly with BCAAs comes down to three main variables: dose, ratio of leucine to isoleucine to valine, and timing. Here’s a quick breakdown:

Dose: A small dusting of BCAAs won't cut it. The optimal dose is around 5-10 grams. Pre JYM, Post JYM, and JYM BCAAs each contain 6 grams of BCAAs per scoop, which is right in the sweet spot and without a doubt considered a full dose.

Ratio: This is a key variable. Leucine is the major mass-builder of the three BCAAs, but that doesn’t mean that more leucine is always better. You want to reap the benefits of all three with a ratio of  2:1:1, leucine to isoleucine to valine, pre-workout (the exact ratio found in both Pre JYM and JYM BCAAs). Post-workout, a slight bump in leucine to a ratio of 3:1:1 (as found in Post JYM) will further promote muscle recovery and growth without being too high of a ratio. Anything above that gets to be insufficient levels of isoleucine and valine for the leucine content.

Timing: I’ve heard many people say that BCAAs taken pre-workout are of little value and BCAAs taken post-workout are overkill if you’re already taking a good protein powder. I vehemently disagree, and this disagreement is backed by science. I believe in full doses of BCAAs both before and after training (regardless of how much protein and the source you’re also consuming) – before because BCAAs are an immediate energy source and they blunt fatigue, and after because they ignite protein synthesis, boost insulin and GH levels and blunt cortisol release.

If you take Pre JYM before training and Post JYM after, your BCAA needs will be covered. That means you won’t need any extra BCAAs during the workout.

 

References:

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Crozier, S. J., Kimball, S.R., Emmert, S. W., Anthony, J. C., Jefferson, L.S. (2005) Oral leucine administration stimulates protein synthesis in rat skeletal muscle. J. Nutr. 135: 376-382.

Crowe, M. J., et al. Effects of dietary leucine supplementation on exercise performance. Eur J Appl Physiol. 2006 Aug;97(6):664-72.

Bolster, D. R., Crozier, S. J., Kimball, S. R., Jefferson, L. S. (2002) AMP-activated protein kinase suppresses protein synthesis in rat skeletal muscle through down-regulated mammalian target of rapamycin (mTOR) signaling. J. Biol. Chem. 277: 23977-23980.

Koopman R, Wagenmakers AJ, Manders RJ, Zorenc AH, Senden JM, Gorselink M, Keizer HA, van Loon LJ. (2005) Combined ingestion of protein and free leucine with carbohydrate increases postexercise muscle protein synthesis in vivo in male subjects. Am. J. Physiol. Endocrinol. Metab. 288(4): E645-653.

Coburn, J. W., et al. Effects of leucine and whey protein supplementation during eight weeks of unilateral resistance training. J Strength Cond Res 2006 May;20(2):284-91.

Mourier, A., et al. Combined effects of caloric restriction and branched-chain amino acid supplementation on body composition and exercise performance in elite wrestlers. Int J Sports Med 1997 Jan;18(1):47-55.

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Nishimura, J., et al. "Isoleucine Prevents the Accumulation of Tissue Triglycerides and Upregulates the Expression of PPAR{alpha} and Uncoupling Protein in Diet-Induced Obese Mice." J. Nutr., March 2010, in press.

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