NAC

Supplements · Antioxidants · Supplement, Typed Supps

A building block your body uses to make its main antioxidant.

Stage by stage

Intake (Capsule): Absorbed in the small intestine.
Small intestine (Absorbed): Absorbed in the small intestine.
Liver (Converted to cysteine): Converted into cysteine, then used to build glutathione, one of the body’s primary internal antioxidants.
Respiratory tissue (Thins mucus): Also thins mucus, which is why it’s used medically for respiratory conditions.

What the evidence supports

Treating paracetamol (acetaminophen) overdose — strong evidence. The definitive use, and it is genuinely life-saving — given intravenously in hospital, not bought in a shop.
Reducing exacerbations in chronic obstructive pulmonary disease — moderate evidence. Trials at higher doses show fewer exacerbations, particularly in people not on inhaled steroids.
Reducing symptoms in trichotillomania and some compulsive behaviours — limited evidence. A few small psychiatric trials with promising but preliminary results.
General detoxification or antioxidant support — insufficient evidence. The marketing claim. Its role in glutathione synthesis is real; the leap to "detox" is not supported.

Typical dose

600 mg twice daily is the dose the COPD question has been tested at. At that dose over one year, the PANTHEON trial in moderate-to-severe COPD found fewer exacerbations; the same dose over two years in mild-to-moderate COPD missed its primary endpoint, with benefit only in a subgroup. So it is the studied dose rather than a proven one. Psychiatric trials have used considerably more, but that is prescribing territory rather than self-experimentation.

Upper limit: No formal UL. 600 mg twice daily was well tolerated in trials running one to two years, with adverse events close to placebo rates.

Timing

Often taken away from other medications, since it can interact with some.

Time to effect

Days–wks: Antioxidant support builds.

Medication interactions

Nitroglycerin: Marked additive blood pressure drop and severe headaches. (high)
Anticoagulants: May add to bleeding risk. (moderate)

Common myth

“NAC boosts glutathione directly.” In reality: It’s a building block for glutathione, not glutathione itself — your body still has to do the converting.