Comparison
N-Acetyl Cysteine vs NMN
Side-by-side of N-Acetyl Cysteine and NMN. Every row below is pulled from the compound schema and will update as our data grows. For deeper reads, follow through to each compound page.
N-Acetyl Cysteine
NAC supplement benefits cover glutathione synthesis, liver and antioxidant support, and hangover recovery. Evidence strongest at 1200-2400 mg/day.
NMN
NMN supplements are oral nicotinamide mononucleotide capsules sold for longevity, energy, and metabolic health. They raise plasma NAD+ 30-90% at 250-1000.
Effects at a glance
N-Acetyl Cysteine
- •Replenishes intracellular glutathione by supplying cysteine, the rate-limiting amino acid for synthesis
- •First-line antidote for acetaminophen toxicity, restoring hepatic glutathione before fulminant injury occurs
- •Reduces sputum viscosity in chronic bronchitis and COPD at 600 to 1200 mg/day over months
- •Modest symptom reductions in OCD and trichotillomania at 1200 to 2400 mg/day across small RCTs
- •Mixed evidence for psychiatric adjunct use in bipolar depression and schizophrenia negative symptoms
- •Inhaled forms can trigger bronchospasm in active asthma; oral use is the standard biohacker route
NMN
- •Plasma NAD+ rises 30-90% at 250-1000 mg/day across human PK studies
- •Tissue NAD+ rise is inconsistent across human trials (Yoshino 2021, Igarashi 2022)
- •No human trials measure hard endpoints (mortality, CV events, cancer); evidence is biomarker-only
- •Most trials cluster at 250-500 mg/day; dose-response above 250 mg/day is poorly characterized
- •FDA position contested; widely sold as supplement but with regulatory uncertainty
- •Marketing claims for fertility and longevity outrun the human trial evidence substantially
Side-by-side
| Attribute | N-Acetyl Cysteine | NMN |
|---|---|---|
| Category | supplement | supplement |
| Also known as | NAC | nicotinamide mononucleotide, beta-NMN |
| Half-life (hr) ↗ | 5.6 | 4 |
| Typical dose (mg) ↗ | 1200 | 250 |
| Dosing frequency | 1 to 3 times daily, split dosing preferred | 1x daily, often morning |
| Routes | oral, iv | oral, sublingual |
| Onset (hr) | 1 | 1 |
| Peak (hr) | 2 | 3 |
| Molecular weight | 163.19 | 334.22 |
| Molecular formula | C5H9NO3S | C11H15N2O8P |
| Mechanism | Deacetylated to cysteine, the rate-limiting precursor for glutathione synthesis; also directly scavenges reactive oxygen species and modulates glutamate signaling. | Direct precursor in the NAD+ salvage pathway; converted to NAD+ by NMNAT enzymes in essentially every tissue. Raised NAD+ supports sirtuin and PARP enzyme activity. |
| Legal status | OTC in most jurisdictions; restricted periods in US history (FDA reclassified 2022) | Contested in US (FDA position 2022); widely sold as supplement; broadly available in EU, UK, Asia |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement (US, post-2022); Rx indications also exist (acetaminophen overdose, mucolytic) | Not scheduled |
| Pregnancy | Used clinically in pregnancy for specific indications; consult clinician | Insufficient data; precautionary avoidance |
| CAS | 616-91-1 | 1094-61-7 |
| PubChem CID | 12035 | 14180 |
| Wikidata | Q413299 | Q418972 |
Safety profile
N-Acetyl Cysteine
Common side effects
- sulfur-like taste or odor
- nausea
- flatulence
- diarrhea
Contraindications
- active asthma attack (inhaled form can trigger bronchospasm)
- known NAC hypersensitivity
Interactions
- nitroglycerin: potentiates vasodilation, risk of hypotension and headache(moderate)
- activated charcoal: reduces NAC absorption when used for acetaminophen overdose(moderate)
- anticoagulants: theoretical additive antiplatelet effect at high doses(minor)
NMN
Common side effects
- mild GI upset (rare)
- occasional headache
- flushing (rare)
Contraindications
- pregnancy and lactation (precautionary, no data)
- active cancer (theoretical concern, not evidence-based)
Interactions
- metformin: no clinically significant interaction documented; both modulate metabolism through different mechanisms(minor)
- chemotherapy agents: theoretical concern about supporting cancer cell proliferation; coordinate with oncology team(moderate)
- CD38 inhibitors: would amplify NMN-induced NAD+ rise; not clinically relevant for most users(minor)
Which Should You Take?
N-Acetyl Cysteine comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC, oral dosing, with a Tier-A outcome catalogued. NMN is the right call when one of the conditionals below applies.
- → If your priority is post-training recovery, pick N-Acetyl Cysteine.
- → If your priority is liver function, pick N-Acetyl Cysteine.
- → If your priority is energy and stamina, pick NMN.
- → If your priority is metabolic health and glucose control, pick NMN.
Edge case: If you want to avoid Contested in US (FDA position 2022); widely sold as supplement; broadly available in EU, UK, Asia, N-Acetyl Cysteine is the more accessible choice.
Default choice: N-Acetyl Cysteine. Wider use case, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for NMN only if your priority sits squarely in the goals it owns above.
This verdict is generated from each compound's schema (goals, legal status, evidence outcomes, dosing route). It updates automatically as our compound data evolves; the deeper read sits on each individual compound page.
Common questions
What is the difference between N-Acetyl Cysteine and NMN?
N-Acetyl Cysteine and NMN differ in category (supplement vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, N-Acetyl Cysteine or NMN?
N-Acetyl Cysteine half-life is 5.6 hours; NMN half-life is 4 hours.
Can you stack N-Acetyl Cysteine with NMN?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
Go deeper