Ferrous bisglycinate is an oral iron used to refill empty stores, not a longevity tonic. In deficient people it rebuilds the oxygen-carrying protein as well as, sometimes better than, ordinary iron, often at lower dose with fewer gut symptoms. Extra iron is the risk when stores are full, in men after middle age, or with genes that store extra iron. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Ferritin | 50–150 ng/mL | Confirms stores; the treatment on/off switch |
| Transferrin saturation | 25–45% | Shows circulating iron available to marrow |
| Hemoglobin | No established target exists; track rise toward the person's own baseline | Confirms oxygen-carrying recovery |
| Mean corpuscular volume | No established target exists; track rise from low toward the lab mid-normal | Tracks iron-limited red-cell production |
| C-reactive protein | Low; ideally <1.0 mg/L | Interprets ferritin; high CRP can hide deficiency |
| Soluble transferrin receptor | No single functional target; track fall toward the lab mean | Separates true deficiency from inflammation |
Cadence: Baseline full iron panel plus C-reactive protein before the first capsule; 4 weeks if anemia is present (hemoglobin); 8–12 weeks for ferritin in non-anemic deficiency; then every 3–6 months if menstrual or training losses continue, or at the next annual panel if the course has stopped and stores are stable