Why do so many bodybuilders know so little about amino acids and protein, the differences in their form and the best times to ingest them? With nothing less that optimal muscle growth at stake, time invested in a little research can pay big dividends - both in terms of physical size and dollars saved.

Amino acids are the building blocks of proteins and muscle tissue. All types of physiological processes relating to sport - energy, recovery, muscle / strength gains and fat loss, as well as mood and brain function - are intimately and critically linked to amino acids. It's no wonder amino acids have become major players in athletes' supplementation, especially among bodybuilders.

The 23 or so amino acids are the molecular building blocks of proteins. According to one accepted classification, 9 are termed indispensable amino acids (IAA, sometimes called essential), meaning that they must be supplied from some food or supplement source; the others, which used to be classified simply as nonessential, are now more correctly termed dispensable amino acids (DAA) or conditionally indispensable, based on the body's ability to synthesize them from other amino acids.

You may not give it much thought when you sink your teeth into a chicken breast (or lentil stew), but the content and balance of amino acids, particularly the ratio of IAA to DAA, is what determines the body and health building value of a protein food or supplement. But that isn't all that matters.

In addition to being influenced by the carbohydrates, fats and total calories associated with it, protein quality is related to the amount of the specific aminos within both the IAA and DAA categories (for example, the amount of glutamine and branched chain amino acids, or BCAAs - leucine, isoleucine and valine). While the amount of IAAs are generally of greater importance, the DAAs are also significant because they're synthesized too slowly to support maximum growth. Even if a source has a perfect amino acid profile for a given individual and lifestyle, another important factor - to what extent these acids are actually delivered to the tissues when needed - must be considered. That, in turn, raises the issues of digestion, absorption, actual bioavailability and the potential value of supplementation.

Eating quality food is the most common way to get amino acids into the diet, especially high protein foods like lean meats and nonfat dairy products. Even some vegetables and legumes can offer high levels of most amino acids. For serious athletes and those on the run, protein powders and pure free form amino acids provide a convenient and effective means to supplement dietary needs.

Why would people pay relatively large sums of money for only a few grams of pure cheaply? Because of bioavailability.

Bioavailability gauges the extent to which an administered substance reaches its site of action or utilization in the body. Bioavailability is thus a measure of the efficiency of delivery - how much of what is ingested is actually used for its intended purpose.

Conceivably, two diets could contain exactly the same amount of particular amino acids (the same amino acid profile) but have significant differences in their absorption. A number of factors affect amino acid bioavailability (see Factors Affecting Amino Acid Bioavailability.

The most reliable way to deliver specific amino acids is to administer the particular amino acids themselves. The most bioavailable source for oral use is powdered free form amino acids.

A singular (unbonded) amino acids can specifically elevate its level in the general circulation within 15 minutes, making it readily available for metabolism at the site where it's needed. Hence, for example, the recommendation to use BCAAs before, during and after training both to prevent central / mental fatigue, as well as to provide a source of energy to help prevent muscle protein catabolism and to speed recuperation.

Muscle tissue will grow in the presence of a number of factors, including exercise, hormones (growth hormone, insulin, testosterone and thyroid) and nutrients. Nutrition science has advanced to the point where athletes who supplement with free form amino acids can get IAAs, high in BCAA content, to the muscles much more effectively.

The key is the window of opportunity that occurs immediately after exercise, when the muscle is especially receptive to nutrients and the blood flow to the exercised muscles remains high. The solution to optimizing recovery and growth in this case could include eating a small meal composed of protein with both simple and complex carbohydrates.

This isn't the current high tech approach, however. For one, if you trained hard, chances are - even if a convenient and light, nutritious meal was readily available - you wouldn't feel like eating. More important, a high protein meal won't put significant levels of amino acids into your bloodstream until a couple of hours after you eat it, especially if blood flow to the gastrointestinal tract has been diminished by a hard training session. The bottom line: Even if you eat the right foods soon after training, the nutrients will arrive at the muscle too late to take full advantage of the window of opportunity.

Supplement manufacturers recognized the potential value of free-form amino use was limited by their expense and a relative lack of convincing supportive research for a number of years, their popularity has recently increased dramatically. Prepackaged workout and recovery drinks containing hydrolyzed (predigested) proteins and often some free-form amino acids now fill gym refrigerators. Capsules and powdered free-form amino acids, although still somewhat expensive, are likewise being used by increasing numbers of top amateur and professional athletes.

The value of free-form amino acids is first and foremost that they don't require digestion. The term 'free-form' means exactly that: They are free of chemical bonds to other molecules and so move quickly through the stomach and into the small intestine, where they're rapidly absorbed into the bloodstream.

Upon absorption, amino acids are processed by the liver. When you eat a steak, for example, only relatively few amino acids escape the metabolic actions of the liver. Yet the liver can process only so many at one time, and taking a dose of 3-4 grams of rapidly absorbed amino acids exceeds the liver's capacity, resulting in the aminos being directed to the tissues that require them, such as muscle in the case of bodybuilder recovering from training. Thus, the concept of 'directed amino acids'.

While sound in theory, does it work in practice? As early as 1990, the Bulgarian national weightlifting team began trials to determine if free-form amino acids were a boost to muscular growth. The work was so successful that part of the study was replicated on the Colorado Springs Olympic Training Center. Since then, top bodybuilders and powerlifters around the world today - including Mr. Olympia Dorian Yates, and 'Mr. Powerlifting' Ed Coan - have benefited from this new research.

Many misconceptions exist about the muscle contraction and the use of energy substrates during heavy during heavy, high-intensity weight training. When you're engaged in a repetitive power workout, a substantial portion of your energy comes from noncarbohydrate sources. When muscle contracts, it uses its stores of adenosine triphosphate (ATP, a substance vital to the energy processes of all living cells) for the first few seconds. The compound used to immediately replenish these stores is creatine phosphate (CP). The recent explosion of creatine supplements in the market attests to its value to hard training bodybuilders and other strength / power athletes.

CP is made from three amino acids: arginine, methionine and glycine. To keep CP and ATP levels high, these amino acids must be elevated in the bloodstream. Traditionally, these proteins have been supplied by foods in the diet. Elevating levels of these amino acids or of CP with conventional foods takes a great deal of time (for digestion) and isn't specific, typically providing levels of fats and carbohydrates that may or may not be desired. The use of free-form amino acids, alone and in combination with creatine supplements, can provide directed source of energy for power and growth.

In fat loss, two major processes must occur: 1) the mobilization and circulation of stored fats in the body must increase; and 2) fats must be transported and converted to energy at the powerhouse site of cells, the mitochondria. Several nutrients can assist in the conversion of fat to energy, including lipotropic agents such as choline, inositol and the IAA methionine which, in sufficient quantities, can help improve the transport and metabolism of fat.

Supplementation with complete IAA mixtures, BCAAs and glutamine can also help keep calorie and food volume down while providing targeted support directly to the muscles, liver and immune systems so critical to optimizing body composition.

The human body has the innate ability to break down muscle tissue for use as an energy source during heavy exercise. This muscle catabolism can cause muscle soreness, shrinkage of muscle tissue and may even lead to injury.

This enemy to bodybuilders is part of a process known as gluconeogenosis, which means producing or generating glucose from noncarbohydrate sources. The part of this reaction that of importance to bodybuilders is known as the glucose - alanine cycle, in which BCAAs are stripped from the muscle tissue and parts of them are converted to the amino acid alanine, which is transported to the liver and converted into glucose.

If you consume supplemental BCAA's. the body does not have to break down muscle tissue to derive extra energy. A study conducted recently at the School of Human Biology, University of Guelph, Onterio, Canada, confirmed that the use of BCAA's (up to 4 grams) during and after exercise can result in a significant reduction of muscle breakdown during exercise.

In addition to BCAAs, arginine is another amino acid that may benefit bodybuilders. Though it did not live up to its early hype, which touted the amino acid's ability to raise growth hormone level, new data indicate that arginine - in large but safe and affordable doses - may be able to raise GH levels by up to 1,000%.

The form an amino acid takes has been a confusing subject for a number of years, partly because of research that demonstrated superior absorption of purified di- and tripeptides fragments. Di- and tripeptides are simply two and three amino acid molecules bound together, respectively, as opposed to the single molecules of free-form amino acids.

The fact is, pure, powdered free-form amino acids are absorbed from the small intestine into the bloodstream and are available to the tissues very quickly. The problem with pure di- and tripeptides isn't their bioavailability but �3Ü available to consumers. Moreover, hydrolyzed proteins such as whey and lactalbumin are not necessarily good sources of di- and tripeptides. They generally contain very few of these amino acid combinations, and what few they have may get lost in the general wash of longer chain peptides contained in these hydrolysates.

So while pure di- and tripeptides are efficient in their ability to be absorbed into the bloodstream, pure free-form amino acids are equal or superior for bodybuilders and other athletes and more important, are as close as your nearest health food store.

How fat you eat a protein source and the length of time it takes for the digested amino acids to be available for use by the body are determined by a number of factors, which include: