sh-Polypeptide-1 for Hair Regrowth - Quick Reference Sheet
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sh-Polypeptide-1 for Hair Regrowth

Created on 09/27/2026 – Quick Reference based on Evidence Review created using AI4L / Opus 5.5 – Audit

sh-Polypeptide-1 is a cosmetic ingredient, a lab-made copy of a human skin-repair protein, sold in scalp serums and clinic treatments for thinning hair. Small, short human studies show modestly denser hair when it is added to standard treatment and delivered by microneedling or injection. Whether a plain leave-on serum works is unshown. Side effects are mild and mostly caused by the needling. (Full Review)

Protocol

Microneedle-assisted protocol
1 mL basic fibroblast growth factor (bFGF) spray, then needling once weekly
For 16 weeks, with twice-daily 5% minoxidil
Clinical topical protocol
3,500 international units (IU) bFGF twice daily
Plus 1 mL 5% minoxidil for 6 months; men with early pattern hair loss
PRP plus bFGF injections
3 sessions, 1 month apart
Platelet-rich plasma (PRP) enriched with bFGF, injected into the skin, alone or with minoxidil
Time to effect
Hair density (microneedle)
16 weeks
Assessment point of the microneedle protocol
Hair density (topical, PRP)
6 months
Topical and PRP combinations
Graft survival
12 months
After hair transplantation

Benefits

Contraindications
  • Active skin cancer on the scalp or face, or melanoma diagnosed within the past 5 years
  • Active cancer treatment, including fibroblast growth factor receptor (FGFR) inhibitors
  • Pregnancy and breastfeeding
  • Known hypersensitivity to the product or any component
  • Active scalp infection, open wounds, or flaring psoriasis or eczema at the application site (needling-assisted use)
  • Platelet count below 50,000/µL, or INR (a clotting-time measure) above 3.0 on anticoagulants (needling- or injection-assisted use)
  • History of keloids (needling-assisted use)
    •
Key Interactions
  • Anticoagulants and antiplatelet drugs (warfarin, apixaban, clopidogrel): Monitor
  • Topical minoxidil: Monitor; potentiating (additive)
  • Retinoids (oral isotretinoin, topical tretinoin): Caution
  • Immunosuppressants (methotrexate, tacrolimus, prednisone): Monitor
  • Heparins (heparin, enoxaparin, dalteparin): Monitor
  • Nonsteroidal anti-inflammatory drugs (aspirin, ibuprofen, naproxen): Monitor
  • Acidic or oxidizing scalp products (glycolic acid, salicylic acid, benzoyl peroxide): Caution
  • Bleeding-prone supplements (fish oil, vitamin E, ginkgo): Monitor
  • Additive topical hair actives (caffeine, rosemary oil, copper tripeptide GHK-Cu, sh-Oligopeptide-1): Monitor; potentiating in theory
  • Platelet-rich plasma and microneedling: Monitor; potentiating
    •

Risk & Side Effects

  • High:
  • Medium: Transient scalp redness, itching, and procedure pain
    •
  • Low: Blood-pressure drop with systemic exposure
    •
  • Speculative: Growth stimulation of existing skin cancers; allergic sensitization to the recombinant protein
    •

Monitoring

Marker Target Why
Hair density (trichoscopy, magnified scalp imaging) No established target; track change from own baseline (hairs/cm²) Primary efficacy readout
Hair shaft diameter (trichoscopy) No established target; track change from own baseline (µm) Detects thickening of shrunken hairs
Ferritin 50–150 ng/mL Iron stores for hair growth
TSH (thyroid-stimulating hormone) 1.0–2.5 mIU/L Rules out thyroid-driven shedding
25-hydroxyvitamin D 40–60 ng/mL Low levels are linked to hair loss
Serum zinc 90–120 µg/dL Deficiency causes shedding

Cadence: Baseline; photographs and trichoscopy at 3 and 6 months, then every 6 months during use; scalp skin check every 12 months; repeat blood tests at 6–12 months if any baseline value was abnormal

Qualitative Assessment

  • Daily shedding in the shower or hairbrush
  • Scalp visibility through the part line or crown in consistent lighting
  • Hair volume, texture, and styling ease
  • Scalp comfort: itching, redness, or flaking after application
  • Self-rated satisfaction at 3 and 6 months
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.