N-acetylcysteine (NAC)

NAC · N-乙酰半胱氨酸

Place · Level 3 · Supplement

FDA 批的对乙酰氨基酚解毒剂 · GSH 前体 · COPD 痰多有用 · 补 GSH营销陷阱

Connected to · 3

cofactor · 1

Glycine
GSH = γ-Glu-Cys-Gly; Cys is rate-limiting (NAC enters here), Gly closes the tripeptide. Both gate GSH synthesis.

contrast · 2

Milk Thistle
Both are sold as liver supplements, and both of their genuinely established clinical roles are intravenous and emergency — silibinin for Amanita poisoning, NAC for acetaminophen overdose — not at shelf doses.
Microplastics
Antioxidants address the oxidative stress particles cause, not the particles. Something like NAC may in theory buffer ROS, but it has no mechanism for clearing plastic — taking it to flush plastic out conflates two different things.

Identity

Stop 1/5

身份 · 半胱氨酸的稳定版

N-acetylcysteine (NAC) = cysteine (Cys) with an acetyl group on the amino nitrogen.

Why not just take cysteine? Because oral cysteine is metabolized rapidly in the gut and liver, has a short plasma half-life, and can oxidize into the more toxic cystine. Acetylation is a protective coat for cysteine: once inside the cell, amidases strip the acetyl group off and release free cysteine.

NAC has a single core identity inside the body: a cysteine supplier.

What is cysteine? The rate-limiting raw material for the glutathione (GSH) tripeptide.

GSH = γ-Glu-Cys-Gly (a tripeptide of three amino acids, with an unusual γ-peptide bond)

Glutamate (Glu) — never scarce in the bodyGlycine (Gly) — never scarce in the bodyCysteine (Cys) — the rate-limiting raw material, because Cys is relatively scarce in the diet and the GSH pool is heavily consumed during oxidative stress and detoxification
So every "mechanism story" about NAC ultimately converges on one thing: raise the intracellular Cys pool so that GSH synthetase (GCL) has substrate to work with.

Read story

Educational content, not medical advice — consult a clinician.

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N-acetylcysteine (NAC)

NAC · N-乙酰半胱氨酸

Place · Level 3 · Supplement

FDA 批的对乙酰氨基酚解毒剂 · GSH 前体 · COPD 痰多有用 · 补 GSH营销陷阱

Connected to · 3

cofactor · 1

Glycine
GSH = γ-Glu-Cys-Gly; Cys is rate-limiting (NAC enters here), Gly closes the tripeptide. Both gate GSH synthesis.

contrast · 2

Milk Thistle
Both are sold as liver supplements, and both of their genuinely established clinical roles are intravenous and emergency — silibinin for Amanita poisoning, NAC for acetaminophen overdose — not at shelf doses.
Microplastics
Antioxidants address the oxidative stress particles cause, not the particles. Something like NAC may in theory buffer ROS, but it has no mechanism for clearing plastic — taking it to flush plastic out conflates two different things.

Identity

Stop 1/5

身份 · 半胱氨酸的稳定版

N-acetylcysteine (NAC) = cysteine (Cys) with an acetyl group on the amino nitrogen.

Why not just take cysteine? Because oral cysteine is metabolized rapidly in the gut and liver, has a short plasma half-life, and can oxidize into the more toxic cystine. Acetylation is a protective coat for cysteine: once inside the cell, amidases strip the acetyl group off and release free cysteine.

NAC has a single core identity inside the body: a cysteine supplier.

What is cysteine? The rate-limiting raw material for the glutathione (GSH) tripeptide.

GSH = γ-Glu-Cys-Gly (a tripeptide of three amino acids, with an unusual γ-peptide bond)

Glutamate (Glu) — never scarce in the bodyGlycine (Gly) — never scarce in the bodyCysteine (Cys) — the rate-limiting raw material, because Cys is relatively scarce in the diet and the GSH pool is heavily consumed during oxidative stress and detoxification
So every "mechanism story" about NAC ultimately converges on one thing: raise the intracellular Cys pool so that GSH synthetase (GCL) has substrate to work with.

Read story

Educational content, not medical advice — consult a clinician.