Adenosylcobalamin is a ready-to-use form of vitamin B12 that reliably corrects deficiency — fatigue, anemia, sore tongue, and early nerve problems. These benefits come from supplying B12, not this specific form. Claims of extra energy and brain protection outrun human evidence. It is well tolerated; the strongest reason to use it is genuine or borderline deficiency. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Serum Vitamin B12 | >500 pg/mL | Confirms adequacy; screens for deficiency |
| Methylmalonic Acid (MMA) | <0.27 µmol/L | Most specific functional marker of B12 at the tissue level |
| Homocysteine | <7–8 µmol/L | Functional marker of B12/folate methylation status |
| Holotranscobalamin (active B12) | >35–50 pmol/L | Measures the fraction of B12 actually available to cells |
| Complete Blood Count / MCV | MCV 80–90 fL | Detects megaloblastic anemia and tracks recovery |
| Serum Folate | >10 ng/mL | Ensures the partner methylation nutrient is adequate |
| Serum Potassium | 4.0–4.5 mmol/L | Guards against hypokalemia during rapid anemia correction |
Cadence: Recheck at 4–8 weeks after starting, then every 6–12 months during maintenance