Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| NAC (N-Acetyl Cysteine) | TUDCA (Tauroursodeoxycholic Acid) | |
|---|---|---|
| Category | Supplements | Supplements |
| Standard Dose | 600-1200mg daily | 250-500mg daily |
| Timing | On empty stomach for best absorption, 30 min before meals. Split doses if >600mg. | With meals for liver support. Some protocols recommend before meals to prime bile flow. |
| Cycle Duration | Cycle 8 weeks on, 2 weeks off (to avoid potential downregulation of endogenous GSH production) | Cycle 4-8 weeks for liver support; ongoing at low dose for chronic liver conditions under supervision |
| Evidence Level | strong_human | Moderate-Strong |
NAC is a precursor to L-cysteine, the rate-limiting substrate for glutathione (GSH) synthesis via glutamate-cysteine ligase. It directly replenishes intracellular GSH, the master endogenous antioxidant. NAC also modulates glutamatergic neurotransmission by stimulating the cystine-glutamate antiporter (system Xc-), influencing extrasynaptic glutamate levels. Additionally, it acts as a mucolytic by cleaving disulfide bonds in mucus glycoproteins.
600-1200mg daily
On empty stomach for best absorption, 30 min before meals. Split doses if >600mg.
Cycle 8 weeks on, 2 weeks off (to avoid potential downregulation of endogenous GSH production)
TUDCA is a water-soluble bile acid conjugate (taurine + ursodeoxycholic acid) with potent hepatoprotective and cytoprotective properties. It inhibits the mitochondrial pathway of apoptosis by preventing BAX translocation to mitochondria and cytochrome c release. TUDCA reduces endoplasmic reticulum (ER) stress by acting as a chemical chaperone, assisting protein folding and reducing the unfolded protein response (UPR). It protects hepatocytes by stabilizing cell membranes, displacing toxic hydrophobic bile acids (chenodeoxycholic, lithocholic) from biliary epithelium, and promoting choleresis (bile flow). Additionally, it has neuroprotective effects via reduction of ER stress in neurons and modulation of the TGR5 bile acid receptor.
250-500mg daily
With meals for liver support. Some protocols recommend before meals to prime bile flow.
Cycle 4-8 weeks for liver support; ongoing at low dose for chronic liver conditions under supervision
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