A lab-made copy of a natural growth-signal protein. Lab and animal work show it can nudge follicle cells to multiply and, paired with other signals, modestly regrow hormone-suppressed hair — but no human proof it works alone. The same signal can also shorten hair's growth phase; it penetrates skin poorly, and long-term safety is unstudied. Best seen as an unproven add-on. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Ferritin (iron stores) | 40–70 ng/mL | Low iron is a common, correctable cause of hair shedding |
| Vitamin D (25-OH) | 40–60 ng/mL | Deficiency is linked to hair-cycle disruption |
| TSH | 0.5–2.5 mIU/L | Thyroid imbalance causes diffuse hair loss |
| Total and free testosterone; DHT | Sex- and age-appropriate | Androgen excess drives pattern loss that a growth factor alone will not overcome |
| Zinc | 90–120 µg/dL | Deficiency can contribute to shedding and poor follicle function |
Cadence: Baseline, then at 3 and 6 months, then every 6–12 months