A general health or dietary supplement is a preparation, usually in the form of a tablet, powder or shake, developed in order to provide nutrition specific to that which your body is lacking, whether due to insufficient dietary nourishment, or a natural deficiency. Supplements can provide nutrients like minerals, vitamins, fatty acids or amino acids.
Whether these supplements fall under the food category or the drugs category is something that has been internationally disputed. However, the Codex Alimentarius Commission, which is the UNs highest authority of food standards, agrees that any supplements containing dietary vitamins or minerals comes under the category of food.
Protein supplements are probably the most common, but there are many different types of protein supplement. Whey isolates for example are a type of protein that will usually contain L-Glutamine for recovery, amino peptides for muscle growth & recovery and, Taurine for improved energy output.
Bodybuilders often consume a powdered protein supplement, the essential tools for building muscle. Protein powder, generally speaking, is usually taken immediately before and after a workout, or instead of a meal. The theory behind taking this type of supplement is that having a regular intake of protein allows for optimum growth and repair of muscle tissue.
Whey proteins (as mentioned above) are the most commonly used kind of protein supplements. It gets absorbed into the body very quickly and provides you with high levels of all essential amino acids. Whey protein is a mixture of the globular proteins found in whey itself, which comes as a by-product of making cheese.
Casein (milk protein) is another kind of protein that has very high levels of Glutamine which aids the bodys recovery. It also contains a substance that lets the body absorb amino acids over a longer time period. This substance is called casomorphin.
You can also concentrate soy protein into a supplement as a vegetarian alternative. It contains all the essential amino acids. A substance in soybeans has weak estrogenic activity, which can improve testosterone levels.