sh-Polypeptide-59 for Hair Regrowth - Quick Reference Sheet

sh-Polypeptide-59 for Hair Regrowth

Created on 08/24/2026 – Quick Reference based on Evidence Review created using AI4L / Opus 5 – Audit

A laboratory-made copy of a human repair protein the body uses to wake resting hair follicles. No trial has tested it on a human scalp, and the protein is far too large to cross unbroken skin. Known harms are minor and local; the real cost is a hair cycle spent finding out, at ten times the price. (Full Review)

Protocol

Single versus split dosing
1–2 mL, once daily
A single evening application is standard; splitting has no pharmacological rationale.
Best time of day
Evening, dry scalp
Allows 6–8 hours of undisturbed contact before washing.
Standard practitioner approach
Monthly, 4–6 sessions
Serum applied immediately after fractional or microneedling passes.
Time to effect
Continuing gains
To 12 months
Regenerative scalp studies report gains continuing to twelve months.
Measurable density change
3–6 months
Nothing meaningful can be judged before one hair cycle; assessment before 16 weeks is uninformative.
Assessing after stopping
6–18 months
Any gain would be expected to regress over one to two hair cycles.

Benefits

Contraindications
  • Current or prior scalp malignancy (basal cell carcinoma, squamous cell carcinoma, melanoma, dermatofibrosarcoma protuberans), absent dermatological clearance
  • Active, untreated actinic keratoses on the scalp (more than isolated lesions, or any thickened, tender or bleeding lesion)
  • Active scarring alopecia in the inflammatory phase (lichen planopilaris, frontal fibrosing alopecia, folliculitis decalvans)
  • Open scalp wounds, ulceration or active scalp infection
  • Known keloid or hypertrophic scarring tendency (if using microneedled delivery)
  • Pregnancy or breastfeeding
Key Interactions
  • Topical minoxidil (caution, additive irritation)
  • Topical tretinoin and other retinoids (caution, barrier disruption)
  • Microneedling and fractional laser (caution, potentiating)
  • Supplements with additive scalp or bleeding effects (caution)
  • Ketoconazole and salicylic acid shampoos (monitor, no direct interaction)
  • Corticosteroid scalp solutions (clobetasol, betamethasone) (monitor, opposing)
  • Supplements supporting the same endpoint (monitor for attribution error)
  • Topical or oral finasteride and dutasteride (no known interaction, mechanistically complementary)

Risk & Side Effects

  • High: Application-site skin reactions
  • Medium: Displacement of therapies with demonstrated regrowth
  • Low: Cancer and cancer-mortality signal; adverse events from microneedling-assisted delivery
  • Speculative: Fibrotic and scarring response in non-wounded scalp; aggravation of PDGFB-driven cutaneous lesions; immunogenicity to a bacterially expressed protein

Monitoring

Marker Target Why
Ferritin 70–100 ng/mL Iron stores gate entry into the growth phase
25-hydroxyvitamin D 40–60 ng/mL Receptor is required for follicle cycling
TSH 0.5–2.0 mIU/L Thyroid dysfunction causes diffuse shedding
Plasma zinc 90–120 µg/dL Deficiency produces brittle hair and shedding
High-sensitivity CRP <1.0 mg/L Flags scalp or systemic inflammation confounding response
Free testosterone and DHT No established target for topical growth-factor use; track against the individual's own baseline Establishes whether an androgen driver is present and untreated
Marked-area hair density ≥10% gain over baseline at 6 months The actual endpoint the serum claims

Cadence: Laboratory panel and standardised photographs at baseline; panel repeated at 3 months if any value was abnormal, otherwise at 6–12 months; photography at 4 and 6 months, then every 6 months; weekly scalp inspection for irritation through month one.

Qualitative Assessment

  • Shedding volume — hairs counted in the shower drain or on the pillow weekly, at a fixed day and time
  • Scalp comfort — itch, burning, tightness or flaking after application
  • Hair shaft feel — coarseness and body of regrowing hairs at the hairline and part
  • Styling behaviour — whether the part line narrows and the hair holds volume through the day
  • Confidence in appearance under bright overhead light, the condition that exposes density loss most