Curated insights • How it Works • Practical Pearls • Evidence Base
| Feature | Primary (Testicular) | Secondary (Pituitary/Hypothalamic) |
|---|---|---|
| Testosterone | Low | Low |
| LH / FSH | High | Low or "Inappropriately Normal" |
| Common Causes | Klinefelter syndrome, Trauma, Mumps | Prolactinoma, Weight loss, Opioids, Iron overload |
Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline.
Note: Testosterone should be measured between 8 AM and 10 AM on two separate occasions to confirm a diagnosis of hypogonadism.