The science bit…
A branched-chain amino acid (BCAA) is an amino acid having aliphatic side-chains with a branch. There are three BCAAs: leucine, isoleucine and valine.
Amino acids are the building blocks of protein.
BCAA’s are also one of the most researched supplements on the market, along with creatine. As a supplement, they are especially helpful in maintaining mass while in a calorie-deficit diet which is because dieting is catabolic, which means it can lead to muscle breakdown.
BCAA’s shouldn't be needed if there is enough Protein within the body. There is a benefit if the body is fasted however as it delays fatigue, this is the same as taking after a high intensity workout. It may also allow you to work harder and for longer.
BCAA’s come in both powder and tablet form, there is no difference between the two, powder is usually the cheaper option and often takes more tablets to get the same dosage as from powder. If you are to take BCAAs you should take 10g-20g per day. The most effective time for you to take BCAA’s is at the time most suitable for you and that you can adhere too, often this is as part of an individual's pre workout.