Understand the source comparison
TB-4 Hair Growth Protocol: Comparison of Administration Methods
Subcutaneous (abdomen) Twice weekly (2mg per dose) 90–120 minutes 18–24 hours Mild erythema in <2% of injections when sites rotated properly Preferred for research protocols. Stable AUC, minimal tissue trauma, allows small-gauge needles Intramuscular (deltoid
No winner is assigned.
This page preserves a source comparison for education. It does not add a rating, recommendation or clinical judgment.
- Subcutaneous (abdomen)
- Twice weekly (2mg per dose)
- 90–120 minutes
- 18–24 hours
- Mild erythema in <2% of injections when sites rotated properly
- Preferred for research protocols. Stable AUC, minimal tissue trauma, allows small-gauge needles
- Intramuscular (deltoid or thigh)
- 45–60 minutes
- 16–20 hours
- Soreness lasting 24–48 hours in 15–20% of injections
- Faster Cmax but no AUC advantage. Higher discomfort limits adherence in multi-week studies
- Topical (scalp application)
- Daily (variable concentration, typically 0.1–0.5mg/mL)
- Not systemically measurable
- Local tissue exposure only
- Scalp irritation in 5–8% of applications
- Ineffective for systemic follicular signaling. TB-4 molecular weight (4963 Da) prevents dermal penetration
- Subcutaneous administration is the standard in follicular regeneration research because it balances bioavailability, injection site tolerability, and adherence feasibility across 12–16 week protocols. Topical formulations fail to deliver TB-4 past the stratum corneum barrier. The peptide's molecular size prevents transdermal absorption, and localized concentrations insufficient to activate dermal papilla cells systemically.