Sh-Polypeptide-9 for Hair Regrowth - Quick Reference Sheet
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Sh-Polypeptide-9 for Hair Regrowth

Created on 06/28/2026 – Quick Reference based on Evidence Review created using AI4L / Opus 4.8 – Audit

A lab-made copy of the body's main blood-vessel-growth signal, added to scalp serums and clinic injections to feed hair roots. The biology is sound, but nearly all human testing used mixtures, often by sellers, so its own effect is unclear. Best seen as a promising but unproven add-on. (Full Review)

Protocol

Topical Serum (most common)
Once or twice daily
Leave-on scalp serum, typically a multi-peptide formula; encapsulation emphasized to aid penetration
Intradermal Injection ("hair cocktail")
Every 2–3 weeks
Clinic growth-factor blends over a course of several sessions (pilot used eight sessions every three weeks)
Dosing Pattern
Repeated low-dose, not single
Applied to clean, dry scalp; consistency matters more than time of day, given short local persistence
Time to effect
Earliest Meaningful Effect
3–6 months
Hair interventions act over hair-cycle timescales; any topical effect judged over a minimum of 3–6 months, not weeks
Blend-Study Assessment
3–4 months
In the blended human studies, regrowth was assessed at three to four months
Full Reassessment
6 months+
Meaningful change cannot be judged sooner than one full hair cycle; reassess at 6 months, then every 6 months

Benefits

Contraindications
  • Psoriasis with active scalp plaques
  • Active or suspected scalp skin cancer
  • Sunburned scalp or recent high-UV exposure
  • Pregnancy or lactation
  • Systemic anti-VEGF cancer therapy
    •
Key Interactions
  • Strong scalp irritants or exfoliating acids
  • Other angiogenic hair actives (copper peptides / GHK-Cu, procyanidins, topical minoxidil)
    •

Risk & Side Effects

  • High: [risks_high]
    •
  • Medium: [risks_medium]
    •
  • Low: Local application and injection-site reactions
    •
  • Speculative: Theoretical concern in VEGF-sensitive conditions; uncertain long-term local effects of repeated VEGF signaling; allergic or hypersensitivity reactions to formulation components
    •

Monitoring

Marker Target Why
Ferritin (iron stores) 50–100+ ng/mL Low iron stores are a common, correctable cause of hair shedding
TSH 1.0–2.0 mIU/L Thyroid dysfunction causes diffuse hair loss that mimics or compounds other causes
Vitamin D (25-OH) 40–60 ng/mL Low vitamin D is associated with hair-cycle disturbance and alopecia areata
Zinc 90–120 µg/dL Zinc deficiency impairs hair-follicle function and protein synthesis

Cadence: Baseline before first application, then reassess at ~3 months, 6 months, and every 6 months thereafter

Qualitative Assessment

  • Subjective reduction in daily hair shedding (pillow, shower drain)
  • Visible new short regrowth or "baby hairs" along thinning areas or the hairline
  • Improvement in hair-pull test (fewer hairs extracted)
  • Perceived increase in overall density, coverage, or hair-shaft thickness
Not medical advice. Educational distillation of a single evidence review. Confirm any decision with a qualified clinician, especially in the presence of prescription drugs or chronic conditions.