Revive - MultivitaminKey Ingredients N Acetyl L Cysteine What is N acetyl cysteine good for? NAC can relieve symptoms of respiratory conditions by acting as an antioxidant and expectorant, loosening mucus in your air passageways. As an antioxidant, NAC helps replenish glutathione levels in your lungs and reduces inflammation in your bronchial tubes and lung tissue. Malic Acid Proponents claim that malic acid can promote energy production, increase exercise endurance, and