With anxiolytic properties, Phenibut is a popular anti-anxiety supplement that is also used to improve sleep quality. Phenibut also has nootropic effects, helping to improve concentration – which is ideal for the gym, sporting performance or even exams. Phenibut has both nootropic & anxiolytic (anxiety-reducing) properties. It is commonly compared to (), , & piracetam, & it has similarities to & differences from all of these substances.