BCAAs (branched-chain amino acids) are metabolized primarily in the liver, but also in muscle tissue and other organs. Once they are ingested, they are broken down into individual amino acids by digestive enzymes in the small intestine and absorbed into the bloodstream.
Once in the bloodstream, BCAAs are transported to the liver, where they are metabolized through a process called deamination. During deamination, the nitrogen-containing amino group is removed from the BCAA molecule and converted into ammonia, which is then converted into urea and excreted by the kidneys.
The remaining carbon skeleton of the BCAA can be used for energy by the body, or it can be used to synthesize other amino acids or proteins. In muscle tissue, BCAAs can also be used directly for energy during exercise or periods of fasting.
It's important to note that the exact metabolic pathway of BCAAs can vary depending on a variety of factors, including dietary intake, exercise, and overall health status.