Porous carbon that grips organic molecules in the gut and leaves the body unchanged. Best supported for binding a swallowed poison before absorption, and for lowering the cholesterol fraction that drives artery plaque, though never against heart attacks. Harms follow the same undiscriminating binding: medicines and supplements swallowed nearby lose much of their effect. (Full Review)
| Marker | Target | Why |
|---|---|---|
| LDL cholesterol | 50–70 mg/dL | Tracks the best-replicated systemic effect |
| Apolipoprotein B | 50–80 mg/dL | Counts every plaque-forming particle |
| 25-hydroxyvitamin D | 40–60 ng/mL | The fat-soluble vitamin most exposed if charcoal is taken near meals |
| Vitamin B12 | 500–900 pg/mL | Water-soluble vitamin with documented binder sensitivity |
| Ferritin | 50–150 ng/mL (women), 75–200 ng/mL (men) | Iron reserve, which binders can erode silently |
| Potassium and magnesium | Potassium 4.0–4.5 mmol/L; magnesium 2.0–2.4 mg/dL | Detects the shifts seen with cathartic-containing charcoal preparations |
| Serum phosphorus | 2.5–3.5 mg/dL | Fell measurably on charcoal in dialysis patients |
| Estimated glomerular filtration rate | Above 90 mL/min/1.73 m² | Baseline kidney filtering for anyone using charcoal for gut-derived waste |
| Serum urate | 4.0–6.0 mg/dL | The target in the one positive flare trial |
| International normalized ratio | No charcoal-specific target exists; track deviation from the individual's own stable pre-charcoal value | Charcoal blunts warfarin absorption |
| Serum indoxyl sulfate | No established target; track the change from the individual's own baseline | The marker charcoal adsorbents lower most consistently |
Cadence: Narrow-margin drug markers repeat at 1–2 weeks after starting or after any change in timing; lipids and electrolytes at 6–8 weeks, then every 6–12 months while use continues; fat-soluble vitamins, vitamin B12 and ferritin annually, or at 3 months if daily multi-gram dosing is sustained.