If you are feeling sick, it's always best to speak with a healthcare professional to get specific advice for your situation. In general, when you are sick, it's important to stay hydrated and consume nutrient-dense foods that can help support your immune system.
BCAAs are typically taken as a supplement to support muscle growth and recovery, but they may not be necessary when you are sick. If you are following a balanced diet that includes protein-rich foods, you are likely already consuming enough BCAAs. It's also possible that taking BCAAs could irritate your stomach or interact with medications you may be taking while sick. So, it's always best to speak with a healthcare professional before taking any supplements when you are feeling sick.