When it comes to science-backed supplements, branched-chain amino acids (BCAAs) fall at the top of the list. There’s more research out there supporting the use of BCAAs than most other supplements, which is why they’ve gained considerable momentum in the bodybuilding and general fitness community over the past few years.
BCAAs are useful for those looking to gain muscle mass, as well as those trying to preserve lean muscle while eating at a caloric deficit. In particular, they're instrumental for bodybuilders trying to lean out in advance of a competition or athletes who've worked hard building up their lean muscle but now want to shred.
For many reasons, eating less than your body requires to maintain its normal functions and support your physical activity can contribute to muscle breakdown. The less body fat you possess, the harder your body tries to latch onto the remainder. This means that your body will resort to lean muscle as fuel, which is not great for anyone looking to achieve a toned, aesthetic physique.
Muscle loss takes place when the body boosts protein breakdown (i.e., catabolism) to free up amino acids in the muscle for energy. At the same time, levels of protein synthesis will also decrease due to your reduced energy intake while dieting. This is a complete double whammy for anyone trying to hold onto their lean muscle mass.
The fundamental equation for muscle mass is: Rate of Protein Synthesis - Rate of Protein Breakdown. If your rate of protein synthesis equals your rate of protein breakdown, you'll be status quo - neither gaining nor losing muscle. If your rate of protein synthesis exceeds breakdown, you're on the road to Gainsville. And if your rate of breakdown exceeds the rate of synthesis, you'll be losing muscle. The latter is what tends to happen when someone gets on an extreme fat loss diet, which elevates protein breakdown and reduces synthesis.
As if that wasn't enough, working out can actually compound the catabolic effects of restrictive dieting. This occurs because the leaner someone becomes, the less energy and available glycogen stores he or she has. If you're excessively tired or weak, you aren't able to perform optimally and your muscles will eventually adapt by using less energy. When this happens, you won't experience any gains in lean muscle mass; in fact, your body may turn to muscle for energy because you're no longer using it to lift heavy loads!
Muscle-Preserving Benefits of BCAAs
If you're looking to thwart muscle loss and even promote muscle gains, you should consider including BCAAs in your stack. There are three BCAAs: leucine, isoleucine, and valine. Leucine in particular stimulates protein synthesis, possibly even to a greater degree than a standard protein on its own. Additionally, BCAAs increase our cells' capacity for protein synthesis, not just the rate of protein synthesis.
On the flip side of the equation, BCAAs also can reduce the speed of protein breakdown. How this phenomenon works is rather complicated, but suffice it to say that BCAAs slow down the cellular processes involved in protein breakdown. If you're decreasing protein breakdown and simultaneously increasing protein synthesis by supplementing with BCAAs, you're going to maintain your lean muscle at the very least (and more likely experience growth).
A Word About Training Intensity
As if their direct effects on muscle preservation weren't enough, BCAAs can also help boost the intensity of your workouts. BCAAs will compete with tryptophan, another amino acid that converts into serotonin, for entry into the brain. The lower your serotonin levels during exercise, the less likely you are to feel fatigued and drained during your training session. By reducing the amount of tryptophan entering the brain and the amount of serotonin ultimately produced, you'll actually be able to train harder for longer periods of time.
What About Whey?
If you fancy yourself a supplement guru, you're probably thinking: "But wait! You can get BCAAs from whey protein. Why should I spend more money on some overpriced BCAA supplement when I can get what I need from my regular shake?"
The problem is that, although whey protein is rich in BCAAs, relying solely on your whey protein to supply BCAAs is not as effective. When you consume BCAAs through whey, they have to be freed up through digestion and then absorbed into your bloodstream. This process can last several hours, even though whey is a relatively fast-digesting protein.
By contrast, BCAAs in supplement form are free-floating, do not require digestion, and can be quickly absorbed into the bloodstream. Even a couple grams of a straight BCAA supplement can spike blood amino acid levels much more than 30 grams of whey protein. This shakes out to a faster, more immediate effect on protein breakdown and synthesis.
Another cool fact: BCAAs bypass the liver and gut when consumed, going directly into the bloodstream. This means that they're available to be used as an energy source virtually instantaneously during your training session (assuming you stock up pre- or intra-workout). Valine and isoleucine are what's called glucogenic amino acids, which means the body can convert them to glucose and use them as an energy source to prevent you from losing steam mid-workout.
How to Dose with BCAAs
Importantly, BCAA supplementation may be unnecessary if you consume enough solid protein sources in your diet - think lean meats, eggs, legumes, cottage cheese, etc. This is because BCAAs are present in the protein-rich foods we regularly consume.
If you're concerned you're not getting enough protein, however, supplementing with BCAAs is essential. How much you need depends on your goals, but a typical dosage ranges anywhere from 5-10 grams. Consider taking your BCAAs pre-workout, intra-workout, post-workout, or some combination thereof for best results. You may also wish to take a dose of BCAAs first thing in the morning to help reverse the muscle breakdown effects that occur overnight from the extended period of fasting.