NAC (N-Acetyl Cysteine)

N-Acetyl Cysteine (NAC) is a derivative of the amino acid cysteine and the direct precursor to glutathione — the body's most important endogenous antioxidant. It has a long history in medicine as a treatment for acetaminophen overdose (where it replenishes liver glutathione) and as a mucolytic for respiratory conditions. Research has expanded to cover psychiatric conditions, fertility, and metabolic health.

NAC replenishes intracellular cysteine, the rate-limiting substrate for glutathione synthesis, boosting cellular antioxidant capacity. It also has direct antioxidant activity through its sulfhydryl group and modulates glutamate signaling by interacting with the cystine-glutamate antiporter — a mechanism relevant to addiction, OCD, and psychiatric applications. In the respiratory tract, NAC cleaves disulfide bonds in mucus proteins, reducing viscosity.

600–1,800 mg/day. 600 mg/day for general antioxidant/glutathione support. 1,200–1,800 mg/day used in clinical studies for PCOS, psychiatric applications, and COPD. Take with food to reduce GI side effects. Split dosing (600 mg twice or three times daily) is common in clinical protocols.

N-Acetyl-L-Cysteine: The standard, bioavailable form used in all clinical research | Liposomal NAC: Potentially enhanced bioavailability; less clinical data vs. standard form

GI side effects common at higher doses — take with food. Should not be taken with nitroglycerin (synergistic vasodilation). At very high doses, may promote oxidative stress paradoxically (glutathione system saturation). Generally well tolerated at 600–1,200 mg/day. This information is educational and is not medical advice.

SuppsBuddy validates the L-form specification and checks that dose is within the clinically studied 600–1,800 mg range. Products relying on non-L-form NAC or with unclear isomer specification receive lower ingredient quality scores.