NAC (N-Acetyl Cysteine)
Also known as: N-Acetyl Cysteine, N-acetyl-L-cysteine.
NAC has decades of clinical use as an acetaminophen antidote — a direct, proven ability to restore hepatic glutathione. That alone earns Tier 1: it is the one ingredient in the stack you cannot substitute when the protocol also includes acetaminophen. Secondary value is acetaldehyde scavenging via cysteine donation.
Where this fits in the system
What it does
NAC is the bioavailable precursor your liver uses to rebuild glutathione — the conjugation pathway it relies on to clear reactive aldehydes that escape ALDH2. Alcohol rapidly depletes hepatic glutathione. NAC refills it and is the reason any acetaminophen in the stack is safe.
How it works
Why NAC and not just cysteine
NAC's acetyl group protects the cysteine from oxidation and first-pass metabolism, so more of the dose reaches the liver intact. Once inside hepatocytes, the acetyl group comes off and the cysteine feeds directly into glutathione synthesis. This is why NAC is the standard of care for acetaminophen toxicity in emergency medicine — it's a glutathione delivery system, not just a cysteine source.
Buying guidance
600 mg capsules, unflavored. NAC has a strong sulfur taste that powder versions cannot hide — capsules are the only practical form. Store airtight; NAC oxidizes in humid conditions.
Deep science · NAC (N-Acetyl Cysteine) — deep dive
Two distinct roles
1. Glutathione restoration. The main act. NAC lets the liver keep quenching reactive oxygen species and clearing electrophiles for as long as the ethanol load keeps coming. 2. Acetaldehyde adduction. Secondary, because the protocol already uses L-cysteine for this. NAC is a backup because free cysteine becomes available once the acetyl group is cleaved.
Acetaminophen safety
Any protocol that includes even a conservative acetaminophen dose in the same 24-hour window as alcohol should include NAC. Alcohol-induced glutathione depletion is the exact mechanism that makes APAP dangerous. NAC neutralizes that risk.
Glutathione kinetics under alcohol stress
Hepatic glutathione (GSH) concentrations drop rapidly during ethanol oxidation, both because GSH is consumed conjugating reactive metabolites and because cysteine supply becomes rate-limiting. NAC raises cysteine availability, which restores GSH synthesis rate.
NAC as an APAP antidote
Sadowska 2012 and earlier emergency-medicine protocols establish NAC as the gold standard for acetaminophen overdose. The mechanism is identical to what the Afterburners protocol exploits: replenish glutathione, let the liver quench NAPQI (the toxic APAP metabolite) before it damages hepatocytes.
Timing across the protocol
NAC is dosed across all five stages because glutathione depletion is a persistent problem — it happens while you're drinking, continues overnight, and leaves you depleted the next day. The Debrief dose is smaller because by then the conjugation stress has passed and you are rebuilding the pool, not defending it.