3HAA is a natural molecule made as the body breaks down a dietary amino acid. Animal studies link higher levels to longer, healthier lives, likely by strengthening cells' stress resistance and calming inflammation. No human trial has tested it, its chemistry can turn damaging at high levels, and regular endurance exercise is the one proven way to raise it. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Serum 3-hydroxyanthranilic acid (3HAA) | No established range (low nanomolar, assay-dependent) | Direct level of the metabolite of interest |
| Kynurenine-to-tryptophan ratio | ~20–40 µmol/mmol | Reflects activity of the pathway that feeds 3HAA |
| Serum tryptophan | 45–80 µmol/L | Substrate availability for the whole pathway |
| Kynurenine | 1.4–2.5 µmol/L | Upstream precursor and marker of pathway flux |
| High-sensitivity C-reactive protein | <1.0 mg/L | Systemic inflammation that drives flux into this pathway |
| Ferritin | 50–150 ng/mL | Iron stores; excess iron amplifies 3HAA's pro-oxidant chemistry |
| Serum copper | 70–110 µg/dL | Copper can drive 3HAA-related free-radical damage |
| Vitamin B6 (plasma PLP) | 30–110 nmol/L | Cofactor for the enzyme making 3HAA's precursor |
| Bone mineral density (T-score) | ≥ −1.0 | Screens for the bone-loss risk suggested by animal data |
Cadence: Every 6–12 months; focused recheck 8–12 weeks after a change; bone density every 1–2 years