sh-Polypeptide-11 is a lab-made copy of a natural human growth protein, sold as an add-on to proven hair-loss treatments in scalp serums, clinic treatments and injection kits. Hair evidence rests mainly on mixed animal studies and one small human injection study of a multi-ingredient product without a comparison group; no human study with a comparison group has tested it alone for hair. Known risks come mostly from needling or injection. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Hair density (trichoscopy) | No established target; track increase from own baseline | Primary response measure |
| Hair shaft diameter | No established target; track increase from own baseline | Detects thickening before density changes |
| Ferritin | 50–100 ng/mL | Iron stores support follicle growth |
| TSH (thyroid-stimulating hormone) | 0.5–2.5 mIU/L | Thyroid disorders cause shedding |
| 25-hydroxyvitamin D | 40–60 ng/mL | Deficiency is linked to hair loss |
| Free testosterone and DHEA-S, an adrenal androgen (women) | Lower half of the laboratory reference range | Androgen excess drives female pattern loss |
| Standardized photographs | Visibly greater scalp coverage than baseline | Global response assessment |
Cadence: Baseline before starting; photographs and trichoscopy (magnified scalp imaging) at 3, 6 and 12 months, then every 6–12 months; blood tests repeated at 6–12 months only if baseline values were abnormal or shedding worsens; injection sites checked 1–2 weeks after each session