sh-Oligopeptide-4, a lab-made copy of the natural repair protein thymosin beta-4, is sold in scalp serums and clinic-injected mixtures for thinning hair. Animal results are promising, but the only test on human scalp follicles pointed the other way; human hair data come only from mixtures studied mostly by their developers. Short-term use looks well tolerated; a long-term cancer concern rests on laboratory work alone. It is banned for tested athletes. (Full Review)

Protocol

Topical cosmetic serum

Once or twice daily

Applied to the scalp; concentration rarely disclosed, so no dose can be specified for retail products

Injected mixture (QR678 Neo)

1.5 mL every 4 weeks

8 sessions injected into the skin layer; the parent QR678 formulation used 1.5 mL every 3 weeks

Research gel regimen

0.5 mg/mL every other day

Recombinant thymosin β4 gel applied for 4 weeks in the scalp trial

Time to effect

Scalp flaking

4-week gel course

Less flaking than placebo at every visit through 20 weeks after stopping

Shedding and hair density

3–6 months

Hair-cycle length means any change needs 3–6 months to judge; QR678 Neo trials assessed results after the fourth and eighth monthly sessions

Persistence after course

One year

Benefits of the 8-session QR678 Neo course reported to persist one year

Benefits

Medium: Less scalp flaking in seborrheic dermatitis

Low: Less shedding and denser hair with injected mixtures containing sh-Oligopeptide-4; faster skin wound healing

Contraindications

Current or former malignancy

Pregnancy or breastfeeding

Active scalp disease such as tinea (fungal infection) or psoriasis

Known hypersensitivity to product ingredients

Athletes tested under the World Anti-Doping Agency (WADA) code

Key Interactions

Angiogenesis inhibitors used in cancer care (bevacizumab, ramucirumab): avoid (theoretical)

Anticoagulants and antiplatelet drugs (warfarin, apixaban, clopidogrel): caution (theoretical) with injected or microneedled delivery

Supplements affecting bleeding (fish oil, Ginkgo biloba, vitamin E): caution (theoretical) with injections

Over-the-counter exfoliants and retinoids (salicylic acid, glycolic acid, retinol): caution (theoretical)

Topical minoxidil (over-the-counter): monitor (theoretical)

Oral 5-alpha-reductase inhibitors (finasteride, dutasteride): monitor (theoretical)

Supplements and cosmetics with additive growth effects (copper tripeptide-1, sh-Oligopeptide-1, sh-Polypeptide-1): monitor (theoretical)

Intralesional corticosteroids (triamcinolone): monitor injection sites

Other interventions (microneedling, platelet-rich plasma, laser therapy): monitor

Risk & Side Effects

Low: Injection and microneedling reactions; immune reactions and systemic effects

Speculative: Promotion of existing tumors; early hair-cycle regression and shedding

Monitoring

Marker	Target	Why
Trichoscopic hair density (hairs/cm²)	No established target; track change from own baseline	Expected to change (primary efficacy marker)
Terminal-to-vellus hair ratio	No established target; track change from own baseline	Expected to change (shift toward thick hairs)
Hair shaft diameter (µm)	No established target; track change from own baseline	Expected to change (thicker shafts)
Hair pull test (hairs released per pull)	No established target; track change from own baseline	Expected to change; a rise is also a safety signal for shedding

Cadence: Baseline, then at 3, 6 and 12 months, then every 6–12 months, using the same site, lighting and magnification

Qualitative Assessment

Visible shedding in the shower, on pillows or in brushes
Perceived hair volume, coverage of the scalp and styling ease
Scalp comfort: itch, redness, flaking or tenderness at treated sites
Satisfaction with appearance in standardized photographs

sh-Oligopeptide-4 for Hair Regrowth

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment