NAC attack. Nac is a pretty harmless chemical that is a precursor to one of the most powerful anti-oxidants produced in our body, namely glutathione. 200mg of nac is a relatively low dose and would be fine to take. One word on nac; because it has a sulfur group, those with intestinal yeast should avoid it because of the potential of feeding the yeast. Consult an expert in functional GI health if unsure.