WebMD states that the possible side effects of branched-chain amino acids include nausea, fatigue and loss of coordination. Additionally, BCAAs may adversely affect individuals who suffer from chronic alcoholism and Lou Gehrig's disease. Overall, however, BCAAs are generally considered safe to use for most people for a period of no longer than six consecutive months.
Branched-chain amino acids naturally occur in foods such as lentils, brown rice, pumpkin seeds, whey protein and beef. BCAAs are most commonly used by athletes to reduce muscle degradation after exercising. According to NYU Langone Medical Center, BCAAs are ideal exercise supplements due to the fact that they are able to pass through the liver directly into the bloodstream. This makes them much easier to burn for energy. It has been observed that BCAA levels in the body decline after muscular exertion, which means that supplementation of the nutrients post-workout is a sensible way of reinfusing the muscles with necessary protein building blocks.
BCAAs help regulate blood sugar levels, which is why WebMD advises that people who are diabetic and insulin dependent use them cautiously. NYU Langone Medical Center notes that BCAAs may also help improve appetite in cancer patients and treat the severity of mania symptoms in patients with bipolar disorder. WebMD advises anyone who is taking thyroid hormones, diazoxide and Parkinson's medications to discuss the use of BCAAs with a doctor prior to use.