Amino Acids make up 75% of the human body, and are essential to almost every bodily function. It's important to know what they are to get a basic grasp of how they can benefit your nutrition. They're what make up proteins, and in fact proteins can also be called polypeptides, which are just long chains of various Amino Acids. There are over three hundred Amino Acids found in nature, but only 23 are know as "Standard". What makes them standard is the fact that they bond together to form proteins. Essential The most important Amino Acids fall into the essential category. The list includes Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan and Valine. They're essential, because the human body cannot synthesize them. It's important to consume complete proteins that contain all these essential Amino Acids so that the body doesn't start to cannibalize itself. BCAA's In particular the branched-chain Amino Acids (BCAA's) Leucine, Isoleucine, and Valine are very important. They have been proven to be useful for decreasing appetite, increasing metabolism and increasing muscle repair making them extraordinary useful for body builders. Non-Essential The remaining Amino Acids can be made in the body. They are Alanine, Arginine, Asparagine, Aspartic acid, Cysteine, Glutamic acid, Glutamine, Glycine, Ornithine, Proline, Selenocysteine, Serine, Taurine and Tyrosine. They're not considered essential, but can become so in certain high stress situations. Additional Functions Amino acids aren't always used up completely to make proteins. The remaining non-protein Aminos become synthesized into other useful molecules. In my opinion here are the three most important to take note of: For example Tryptophan is actually a precursor to Serotonin, the neurotransmitter that contributes to feelings of happiness and well-being. Serotonin also helps regulate mood, appetite, memory and sleep. Turkey is high in Tryptophan, so after Thanksgiving dinner it makes sense that people will feel happy and sleepy from all the Serotonin produced. In the same way Tyrosine acts as a precursor to the neurotransmitter Dopamine. Dopamine is produced in the brain and plays a major role in reward driven learning. Any positive reward will trigger a release of Dopamine in the brain. Dopamine is known as the feel good chemical. The last one I'd like to talk about is Arginine being a precursor to Nitric Oxide (NO). Nitric Oxide is beneficial for Athletes because it dilates blood vessels, which causes an increase in blood flow. More blood sending nutrients to your muscles makes them bigger and stronger. Supplement Recommendations: The amount you need depends on a few variables such as body weight, gender, diet and type of training. I'll start by saying that the best place to get Amino Acids from is your diet. This should cover most people's needs, but when times are tough there are easy inexpensive ways to supplement additional Aminos. Protein powder is perfect, because protein is made out of Amino Acids. Most powders you can buy even contain extra BCAA's, Glutamine or Taurine. Getting all the protein you need (1 gram per pound of body weight) should mean you're also fulfilling your Amino Acid requirements. There are times of high stress, when it can be beneficial to use Amino Acids supplements, because unlike protein the direct supplements can be absorbed without being digested. Find out what you need depending on your situation and how you're feeling. Some general advice I can give is BCAA's help in situations of low food like dieting. Glutamine and Taurine help give the body extra energy to help deal with overtraining. The two precursors I mentioned before Tryptophan and Tyrosine facilitate the production of neurotransmitters that help regulate mood, which makes them perfect for dealing with hard times at work, performance anxiety, and lack of sleep. Do your research and figure out what would benefit you the most.