What is N-Acetyl (3,4-Dihydroxybutyl) Cysteine (NADB)? And Why Does the Toxin Zoomer Test for It?

Glutathione-derived mercapturic acid

N-Acetyl (3,4-Dihydroxybutyl) Cysteine (NADB) is a urinary mercapturic acid formed when reactive chemical byproducts are conjugated to glutathione and N‑acetylated for excretion. Measuring NADB gives clinicians a window into recent exposure to certain volatile organic compounds (VOCs) and the activity of phase II detoxification pathways.

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N-Acetyl (3,4-Dihydroxybutyl) Cysteine (NADB)

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About N-Acetyl (3,4-Dihydroxybutyl) Cysteine (NADB)

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About N-Acetyl (3,4-Dihydroxybutyl) Cysteine (NADB)

Overview and History

NADB is a mercapturic acid — an N‑acetylcysteine conjugate produced when electrophilic metabolites are neutralized by glutathione, then processed and excreted in urine. Biochemically it reflects sequential detox steps: glutathione conjugation (often GST‑mediated) followed by enzymatic N‑acetylation. This compound has been used in occupational and exposure studies as a biomarker for parent compounds such as 1,3‑butadiene and related combustion or industrial VOCs. Rather than a biological “function” in itself, NADB serves as a traceable output of the body’s handling of reactive environmental chemicals and phase II clearance activity.

Interpreting Highs and Lows

Elevated urinary NADB may indicate higher recent exposure to parent VOCs or active conjugation of reactive metabolites; it can also reflect effective glutathione‑dependent clearance when interpreted alongside other markers. Low or undetectable NADB may indicate low recent exposure, rapid elimination before sampling, or limited formation of the specific conjugate — which can occur if glutathione availability or relevant enzyme activity is reduced. Interpretation is most informative when considered with other urinary toxicants, timing of collection, and detox‑related genetic results from the full panel.

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NADB is included in the Toxin Zoomer to detect exposure-related mercapturic metabolites and to assess glutathione‑dependent phase II conjugation. Paired with other toxicant measurements and detox genetics, NADB helps clinicians link exposure sources with individual clearance patterns to guide focused, capacity‑aligned assessment.

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N-Acetyl (3,4-Dihydroxybutyl) Cysteine (NADB) FAQs

What is N-Acetyl (3,4-Dihydroxybutyl) Cysteine (NADB) and why is it important?

NADB is a urinary breakdown product formed when reactive chemical metabolites are detoxified and prepared for excretion. It serves as a measurable trace of recent exposure to certain volatile organic compounds and of the body’s glutathione‑based conjugation activity. That information helps show whether exposures and detox processes are active, which can guide further testing and interpretation within a broader exposure profile.

What does it mean if my N-Acetyl (3,4-Dihydroxybutyl) Cysteine (NADB) levels are low?

Low NADB can mean you had little recent exposure to the specific parent compounds, or that the sample was collected after the metabolite was already cleared. It can also reflect reduced formation of the conjugate due to low glutathione or lower activity of conjugating enzymes. Clinical interpretation should use other toxicant results, collection timing, and detox genetics to clarify what low levels suggest.

What does it mean if my N-Acetyl (3,4-Dihydroxybutyl) Cysteine (NADB) levels are high?

Higher NADB suggests greater recent formation and urinary excretion of that mercapturic metabolite, which can be due to higher exposure to certain VOCs or active glutathione conjugation of reactive intermediates. Elevated levels are a signal to evaluate exposure sources and to interpret them alongside other panel measurements and genetic detox markers for full clinical context.

Why is this biomarker included in the Toxin Zoomer?

NADB provides a targeted readout of phase II glutathione conjugation for specific VOC‑derived metabolites. When combined with other urinary toxicants and detox genetics in the Toxin Zoomer, it helps clinicians connect exposure signatures with individual clearance capacity, improving precision in exposure assessment and follow‑up planning.

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