N-Acetylcysteine (NAC)
NAC is a precursor to the antioxidant glutathione and an established antidote for paracetamol (acetaminophen) overdose. PED users take it as general liver and antioxidant support and, less well founded, for blood-pressure and lipid benefit. It has genuine clinical pedigree in overdose and as a mucolytic, but its value as a routine on-cycle hepatoprotectant is extrapolated rather than proven.
01 Overview
NAC is deacetylated to cysteine, the rate-limiting substrate for glutathione synthesis. By replenishing hepatic glutathione it protects hepatocytes from oxidative and reactive-metabolite injury — the basis of its life-saving role in paracetamol poisoning. It is also a licensed mucolytic and has been studied in NAFLD, contrast nephropathy and psychiatric conditions with mixed results.
In the PED community it is taken during cycles for presumed liver protection and antioxidant support. The overdose and mucolytic evidence is strong, but data specifically supporting NAC against anabolic-steroid liver strain are absent, and NAFLD trials are inconsistent. It is inexpensive and well tolerated, which sustains its popularity independent of hard evidence.
02 Mechanism
Supplies cysteine to raise intracellular glutathione, directly scavenges reactive oxygen species and reactive drug metabolites, and cleaves disulphide bonds in mucus (mucolytic action).
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Paracetamol overdose (label) | 150–300 mg/kg | IV | Hospital protocol dosing, reference only. |
| General antioxidant / liver support | 600–1200 mg/day | Oral | Typical supplement range, often split twice daily. |
| Higher supplemental use | 1800–2400 mg/day | Oral | Upper anecdotal range; GI upset becomes more likely. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Raised glutathione / antioxidant capacityReliably increases hepatic and systemic glutathione, the basis of its antidote and antioxidant roles. | measurable | Clinical | |
| Possible NAFLD marker improvementSome studies show improved transaminases in fatty liver disease, but results are mixed and not specific to AAS use. | modest / inconsistent | Observational |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Gastrointestinal upsetNausea, vomiting and abdominal discomfort, more likely with large oral doses. | Mild | Common at higher doses | Clinical | |
| Bronchospasm / hypersensitivityAnaphylactoid reactions, mainly reported with intravenous dosing; oral reactions are uncommon. | Moderate | Rare | Clinical |