An oral medication that raises a man's own testosterone by releasing a brake in the brain, keeping the testes active so sperm production is generally preserved — unlike testosterone gels or injections. The evidence that it raises testosterone is strong and consistent, but whether men actually feel better is less firmly established, and long-term safety data are limited. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Total testosterone | 500–800 ng/dL | Primary efficacy marker |
| Free testosterone | 100–200 pg/mL | Reflects usable, unbound hormone |
| Luteinizing hormone (LH) | Rising above baseline; mid-normal or above | Confirms the axis is being stimulated |
| Follicle-stimulating hormone (FSH) | Rising above baseline | Supports sperm production |
| Estradiol (E2) | 20–40 pg/mL | Detects excess estrogen from the testosterone rise |
| Hematocrit | 40–50% | Detects blood thickening |
| Sex hormone-binding globulin (SHBG) | 20–45 nmol/L | Interprets total vs. free testosterone |
| Prostate-specific antigen (PSA) | < 1.5 ng/mL (age-dependent) | Prostate safety before raising testosterone |
| Semen analysis (sperm concentration) | > 15 million/mL | Confirms fertility preservation |
Cadence: First recheck at about 4–6 weeks, again at 3 months, then every 6–12 months once stable