A standardised root extract taken to raise the body's own testosterone. Combined results from controlled trials support a rise, largest in men who start low. Trials also record fewer age-related male symptoms, less fatigue and stronger sexual desire. Claims of firmer erections, more strength and better fertility are thinner. Much supportive work was manufacturer-funded; product contents remain the main uncertainty. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Total testosterone | 600–900 ng/dL | The primary target of the intervention |
| Free testosterone | 15–25 ng/dL | The unbound fraction that reaches tissue; can move when total does not |
| Sex hormone-binding globulin | 20–40 nmol/L | The carrier protein; a fall here raises free testosterone without changing total |
| Oestradiol (sensitive assay) | 20–30 pg/mL in men | Detects excess conversion of testosterone, the step the extract is proposed to block |
| Luteinising hormone | 2–6 IU/L | Distinguishes a testicular from a pituitary or adrenal route of any rise |
| Haematocrit | 40–48% | Detects androgen-driven thickening of the blood before it becomes a clinical problem |
| Alanine and aspartate aminotransferase | Both below 25 U/L | The two enzymes that rise when liver cells are injured; the one serious reported event |
| Prostate-specific antigen | Below 1.0 ng/mL under 50; below 2.0 ng/mL from 50 | Baseline before any androgen-raising intervention in men from age 40 |
| Fasting glucose | 75–85 mg/dL | Insulin resistance suppresses testosterone and blunts any response |
Cadence: Baseline before the first dose, drawn fasting between 07:00 and 10:00 and a low first value confirmed on a second morning. Hormone panel repeated at 4 weeks and 12 weeks, then every 6 to 12 months while use continues. Liver enzymes and haematocrit rechecked once at 8 to 12 weeks and thereafter annually.