Milk thistle extract has been shown in numerous studies to support healthy liver function. Antioxidants protect your healthy cells from damaging free radicals. Free radicals are molecules that can cause damage to healthy cells and make them unable. Standardized milk thistle extract is known as silymarin. Silibinin is the most active chemical and is hypothesized to function by displacing toxins trying to bind to the liver as well as by causing the liver to regenerate more quickly.