Iron/ferritin

By Nelson Vergel — chemical engineer, patient advocate, and 34+ years on TRT | Last updated: July 2026 You feel flat. Training that used to feel easy now drags. You're sleeping enough, your testosterone looks dialed in, and your doctor says your bloodwork is "normal." So why the fatigue? For a...

* The lack of standardization and harmonization among ferritin assays results in significant variability in clinical values. These assays have different reference ranges and numerous clinical cut-offs for interpreting anemia and iron toxicity. This inconsistency is due to manufacturers using...

* The current world health organization guidelines have the lower limit of normal for serum ferritin at 15 micrograms per liter, whereas we know from physiological studies… that a more appropriate threshold is probably 25-to-30, maybe even as high as 50 micrograms per liter Iron...