Whey is what is known as a complete protein, hence why it tops this list, as well as many others in the supplement world. It's a kind of protein that is packed with branched chain amino acids such as leucine, isoleucine and valine and as such are the building blocks of muscle. It gets it's great reputation thanks to its ability to build mass quickly, its ready bioavailability, its cost, support of fat burning, decreasing appetite, boosting immunity and its accessibility to many. Along with this some studies have shown its ability to increase glutathione which is an important antioxidant.
Branch Chain Amino Acids (or BCAAs as they're known in the supp shop) are one of the most common and supported supplements available to those looking to increase muscle mass, particularly whilst dieting. By the very nature of dieting, you are putting your body into calorie deficit - burning more energy than you're bringing in. This can shave off volume from your muscles as once your body finished metabolising fat for energy.
Amino Acids are the building blocks for protein, and BCAAs are known to play a key role in protein synthesis, speeding up the process and even increasing the cells' capacity to create protein. Essentially, they'll ensure that your muscles are effectively synthesising protein for repair and growth.
Creatine is another widely used yet largely misunderstood supplement. In its natural state in the body, the chemical is responsible for the energy behind short-term high intensity efforts under 30 seconds, such as weight lifting or sprints. The way creatine does this is by recreating a chemical called adenosine triphosphate (ATP) once it's been used up by these maximal efforts. When creatine levels are low, ATP cannot be replenished, sending our energy level plummeting. Supplementing with creatine replenishes these ATP stores which in turn leads to muscle strength increases and power output.
In its natural environment, glutamine is an amino acid found in the bloodstream, that effects itself on the immune system. Medically used for patients recovering from a variety of body traumas, glutamine can be found in athletes gym bags for it's anabolic effects on the muscles. What does this mean to non-scientists? Basically, it promotes muscle growth by promoting fat burning for energy, rather than muscle fibres. Glutamine is also useful in safeguarding the immune system from the stress of workouts, and enhancing glycogen storage in the muscles.
You've probably heard of taurine thanks to epic marketing campaigns from energy drink powerhouses like RedBull and Mother. It's been shown to regulate water balance and nutrient absorption preventing dehydration, increase energy and alertness, muscle contractions and heartbeat. Unlike other amino acids, taurine doesn't actually aid in muscle growth (directly) as it doesn't bond with other aminos.