3HAA is a natural product of the body's breakdown of tryptophan, an amino acid in protein foods, studied for healthy aging and obtainable only as a laboratory chemical. Raising it lengthened life in worms and, in small early studies, in mice. No person has taken it in a controlled trial; tumor, bone and blood-vessel concerns remain unresolved. Sustained endurance exercise is the one tested human way of raising it. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Serum 3HAA | No established target; track change from own baseline | Confirms exposure |
| Plasma quinolinic acid | No established target; track change from own baseline | Downstream harm signal |
| Urinalysis (blood) | Negative; 0–2 red blood cells per high-power field | Bladder safety |
| Vitamin B6 (PLP) | ≥30 nmol/L | Supports 3HAA production |
| LDL-C | <100 mg/dL | Tracks lipid effect |
| Triglycerides | <100 mg/dL | Tracks lipid effect |
| hs-CRP | <1.0 mg/L | Inflammation response |
| CBC with differential (lymphocytes) | 1.5–3.0 × 10⁹/L | Immune suppression |
| eGFR (with cystatin C in muscular adults) | >90 mL/min/1.73 m² | Kidney clearance |
| Ferritin and serum copper | Ferritin 50–150 ng/mL; copper 80–120 µg/dL | Metal load |
| DXA bone density | T-score above −1.0 | Bone-loss signal |
Cadence: Baseline, then 4 weeks, 12 weeks and every 6 months. Urinalysis and CBC at each timepoint; serum 3HAA and quinolinic acid at 12 weeks, then every 6 months; lipids and hs-CRP at 12 weeks; DXA after 12 months.