Stable free radicals are molecules that have unpaired electrons but do not readily react with other substances. Unlike typical free radicals, which are highly reactive and can cause damage to cells, stable free radicals can exist in a more balanced state. They play important roles in various biological processes, including signaling and maintaining cellular health. One well-known example of a stable free radical is nitric oxide, which is crucial for regulating blood flow and immune responses. These radicals can also be found in certain antioxidants, which help protect cells from oxidative stress while maintaining their stability.