Comparison
N-Acetyl Cysteine vs TUDCA
Side-by-side of N-Acetyl Cysteine and TUDCA. 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.
TUDCA
TUDCA is the taurine-conjugated form of ursodeoxycholic acid, a bile-acid molecule with replicated effects on liver function, ER stress, and bile flow.
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
TUDCA
- •Bile-acid molecule (taurine-conjugated UDCA) with chemical chaperone activity at the endoplasmic reticulum
- •Established pharmaceutical use for cholestasis and primary biliary cholangitis at 500-750 mg/day
- •Reduces ER stress and stabilizes misfolded proteins; the mechanistic basis for emerging ALS / retinal applications
- •Modest improvements in NAFLD markers and insulin sensitivity at 500-1,750 mg/day in small trials
- •Mitochondrial protection signal in animal models drives the longevity-supplement positioning
- •Generally well-tolerated; mild GI effects are the main dose-dependent issue
Side-by-side
| Attribute | N-Acetyl Cysteine | TUDCA |
|---|---|---|
| Category | supplement | supplement |
| Also known as | NAC | tauroursodeoxycholic acid, taurine-conjugated UDCA |
| Half-life (hr) ↗ | 5.6 | 4 |
| Typical dose (mg) ↗ | 1200 | 500 |
| Dosing frequency | 1 to 3 times daily, split dosing preferred | daily, divided into 2 doses with food |
| Routes | oral, iv | oral |
| Onset (hr) | 1 | 1 |
| Peak (hr) | 2 | 2 |
| Molecular weight | 163.19 | 499.7 |
| Molecular formula | C5H9NO3S | C26H45NO6S |
| Mechanism | Deacetylated to cysteine, the rate-limiting precursor for glutathione synthesis; also directly scavenges reactive oxygen species and modulates glutamate signaling. | Bile-acid signaling via FXR/TGR5 receptors; chemical chaperone reducing ER stress and unfolded protein response; mitochondrial protection through reduced outer-membrane permeabilization. |
| Legal status | OTC in most jurisdictions; restricted periods in US history (FDA reclassified 2022) | OTC dietary supplement (US); pharmaceutical in Italy and several Asian countries |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement (US, post-2022); Rx indications also exist (acetaminophen overdose, mucolytic) | OTC supplement |
| Pregnancy | Used clinically in pregnancy for specific indications; consult clinician | Insufficient data for supplement use; UDCA used in cholestasis of pregnancy |
| CAS | 616-91-1 | 14605-22-2 |
| PubChem CID | 12035 | 9848818 |
| Wikidata | Q413299 | Q418751 |
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)
TUDCA
Common side effects
- mild GI upset
- diarrhea (dose-dependent)
- constipation (rare)
- nausea
Contraindications
- complete biliary obstruction
- pregnancy / lactation (insufficient supplement-dose data)
- active GI disease without medical supervision
Interactions
- cyclosporine, oral contraceptives, fat-soluble vitamins: modest absorption changes via altered bile-acid pool(minor)
- phenylbutyrate: synergistic for ALS use (Relyvrio combination); consult clinician(moderate)
Which Should You Take?
TUDCA comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC dietary supplement, oral dosing, with a Tier-A outcome catalogued. N-Acetyl Cysteine 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 mitochondrial function, pick TUDCA.
- → If your priority is healthspan extension, pick TUDCA.
Default choice: TUDCA. Lower friction to source, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for N-Acetyl Cysteine 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 TUDCA?
N-Acetyl Cysteine and TUDCA 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 TUDCA?
N-Acetyl Cysteine half-life is 5.6 hours; TUDCA half-life is 4 hours.
Can you stack N-Acetyl Cysteine with TUDCA?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
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