SubEx

Amino acid

N-Acetylcysteine (NAC)

The hospital antidote to paracetamol poisoning, also sold as a supplement. As an antidote its window closes hours before the poisoning feels like anything.

Findings
1
Best evidence
★★☆
Open questions
0

At a glance

Myth check

NAC (N-acetylcysteine) helps your body make glutathione, one of the most powerful antioxidants it has, and a daily capsule keeps your liver's levels topped up so it can neutralise toxins and detox.

N-acetylcysteine (NAC) has one proven liver job, and it is in hospital: it is the antidote to a paracetamol (acetaminophen) overdose, and among people at risk of liver damage, injury developed in about 6% when it was started within 10 hours of the overdose against about 26% when it was started between 10 and 24 hours. Whether a daily capsule tops up glutathione is less clear. In one small trial of 36 people, 1,200 mg a day for a month restored glutathione only in the 12 who started with low levels, and changed nothing in those whose levels were normal or high. Outside overdose, a review of the two trials in hospital patients with liver failure from other causes found no clear effect on survival. None of these studies tested whether NAC helps a healthy liver detox.

NAC earned its liver reputation as a hospital antidote for overdose, and the daily detox capsule borrows it; the one small trial of everyday use raised glutathione only in people who started low.

The findingsStrongest first
1↓
Physical & bodyThe antidote works best hours before an overdose feels like anything

Liver injury followed in 6.1% of 2,540 treated patients when the antidote started within 10 hours, and in 26.4% when it started at 10 to 24 hours.

★★☆Single study — solid evidence, such as one good trial or a large observational dataset, but not replicated at the top tier.This was an open treatment series with partly historical comparisons, because withholding an antidote to build a control group was not available. It dates from 1988 and the regimens have changed since, most notably to a shorter two-bag drip. The time bands rest on when people said they took the tablets, which is unreliable after an overdose and missing altogether when doses were spread across days. What survives all of that is the steepness of the gradient, which later guidelines reproduce.Click to keep this openRelieve pain
Sources3 behind this page

Taken with something else

What the evidence says about combining N-Acetylcysteine (NAC) with each of these. The marker is how well established the interaction is; a caution is about the hazard, which is a different question.