A bitter East Asian bark, usually sold blended with magnolia or orange peel. Its active compounds barely enter the bloodstream, so much of the effect may stay in the gut. The best human signal is lower stress hormone output and better mood; weaker signals cover knee comfort, weight and blood fats. It raises blood levels of some prescription medicines. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Alanine aminotransferase | 10–26 U/L (men), 8–22 U/L (women) | Detects liver stress from alkaloid load or from a co-administered drug |
| Total and direct bilirubin | Total 0.3–1.0 mg/dL; direct below 0.3 mg/dL | Tracks the albumin-displacement mechanism behind the newborn warning |
| Potassium | 4.0–4.5 mmol/L | The transient severe event in the only bark-only trial was low potassium |
| Estimated glomerular filtration rate | Above 90 mL/min/1.73 m² | Rodent kidney tubular change at high doses makes filtration the relevant safety margin |
| High-sensitivity C-reactive protein | Below 0.5 mg/L | The inflammation marker that moved most in the joint trial; the main efficacy readout |
| Fasting glucose and glycated haemoglobin | Glucose 75–86 mg/dL; glycated haemoglobin 4.8–5.2% | Captures the glucose-lowering effect and any additive low-blood-sugar risk |
| Lipid panel | LDL below 100 mg/dL; HDL above 55 mg/dL; triglycerides below 80 mg/dL | The cardiovascular readout that improved most in the eight-week pilot |
| Morning salivary cortisol | 0.10–0.35 µg/dL at waking | The primary endpoint of the stress trials and the clearest efficacy signal |
| Prostate-specific antigen | Below 2.5 ng/mL, or stable against personal baseline | Relevant only where prostate intent applies; the bark may lower the reading |
| Cyclosporine or tacrolimus trough level | No established target; tracked against the individual's own pre-supplement trough | Direct measurement of the highest-consequence interaction |
Cadence: Liver enzymes and potassium at four weeks, the full panel at three months, then every six months; levels for interacting prescriptions at one and four weeks after any dose change