If you've made the commitment to start investing time regularly in a weightlifting workout program, the next step that you must take is getting your nutrition and supplement protocol in line so that you are able to maximize the results you get from your workouts.
Failing to take into account this portion of the equation is a critical mistake. Not only will you not be as effective at changing your body composition, but you likely won't have the energy you otherwise would to put into those workouts.
Getting a full spectrum of amino acids tops the list of important "musts" that need to be covered, so that's where you should start off when planning your supplement program.
The following are some of the top reasons why investing in a BCAA supplement is a smart move.
1

BCAAS AND THE IMMUNE SYSTEM

The first thing you'll experience if you choose to supplement your diet with branched-chain amino acids (BCAAs) is immune system support. Every time you go into the gym and lift weights, you are placing an enormous amount of stress on the body. If the body is not able to fully tolerate this stress level, you're going to see problems develop regarding muscle recovery, and possibly an increased likelihood of illness.


EVERY TIME YOU GO INTO THE GYM AND LIFT WEIGHTS, YOU ARE PLACING AN ENORMOUS AMOUNT OF STRESS ON THE BODY.
Because the essential amino acids cannot be produced by the body and must be consumed directly, if you fail to get these in your body, it will not have everything it needs to maintain a normal, healthy immune system. Further, one study performed by the Laboratory of Human Nutrition for Athletes suggested that taking branched-chain amino acids around exercise also decreased the immune system response that is demonstrated.
3

PROTECTION AGAINST AMINO ACID DEFICIENCIES

The second big benefit you'll experience if you supplement your diet with branched-chain amino acids is that you can rest assured that you will not experience deficiencies in overall amino acid levels. Many of those who are on highly restricted diets such as those prepping for contests or those who adopt a vegetarian way of eating will run the risk of not taking in the essential amino acids, so this supplement helps make up for that.
Care must always be taken in terms of food selection when limiting protein-rich foods such as meat products, whole eggs, and dairy. Overlooking this on your diet could have very large consequences, so be sure it isn't a mistake you make.
As a working athlete, you're probably also concerned with the rate of protein synthesis taking place in your body. Since new muscle mass can only be built when protein synthesis takes place and old tissue is repaired while new tissue is built up, the faster this process progresses, the quicker you will see results.
Part of making sure this process starts up is providing the right nutrients: both the building blocks to build the tissue and the energy to get the job done. Glucose from carbohydrates will satisfy the latter need, while the amino acids you take in will help satisfy the former. Branched-chain amino acids appear to speed this rate even further when combined with the insulin response that comes from ingesting the glucose molecules.
3

PREVENTION OF LEAN MUSCLE MASS LOSS


Finally, any time your body is under stress or you are required to take a break from training and doing very little physical activity, you will be at a risk for lean muscle-mass loss. This is particular significant in those who are undergoing surgical procedures, so research has been conducted to determine what, if anything, can be done to prevent this catabolic effect.
One study suggested that when patients received a solution containing the three essential amino acids compared to those who were receiving only a dextrose solution, they did not move into a negative nitrogen balance during the recovery period, which is indicative of lean muscle tissue loss.
From this study we can also predict that if you're out because of a serious injury of any kind, that is the time it will be especially important to make sure you're supplementing with branched-chain amino acids as early as possible, as it's this quick treatment that helps to speed the rate of recovery in the body as well as maintain nitrogen balance.
Many individuals do a good job of making sure they are taking in enough protein and carbohydrates during the pre- and post-workout period. Often, they will even go to the extent of looking into other supplements that will help them take their results just that little bit further, such as creatine or glutamine, but yet still overlook the benefits of a good branched-chain amino acid product.
Don't be the person to let this hinder your goals. Although it may seem like a rather simple supplement, it's one that will really make a difference in your training, particularly if you are already running a deficiency.  
REFERENCES
  1. Atamian, S. et al. (1979). Infusion of the branched-chain amino acids in postoperative patients: Anticatabolic Properties. Annals of Surgery Journal. Vol 190(1):18-23.
  2. Bacurau, R.F.P. et al. (2002).athle Branched-chain amino acid supplementation and the immune response of long distance tes. Nutrition; Vol 18:Issue 5 (376-379).
  3. Garlick, P.J. & Grant, I. (1988). Amino acid infusion increases the sensitivity of muscle protein synthesis in vivo to insulin. Effect of branched-chain amino acids. Biochemistry Journal. V. 254(2).