Ingredient or product comparison
Hair Growth Peptides 2026 Update: Clinical Evidence Comparison
Thymosin Beta-4 (TB-4) Binds G-actin in dermal papilla cells, promotes cellular migration and anagen extension 4,963 Da Subcutaneous injection (500 mcg 2×/week) 43% increased dermal papilla proliferation in vitro; 6.2-week mean anagen extension in 32-week tria
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- Thymosin Beta-4 (TB-4)
- Binds G-actin in dermal papilla cells, promotes cellular migration and anagen extension
- 4,963 Da
- Subcutaneous injection (500 mcg 2×/week)
- 43% increased dermal papilla proliferation in vitro; 6.2-week mean anagen extension in 32-week trial (Stanford, 2025)
- Strongest evidence for anagen extension. Requires injectable administration due to molecular size
- Copper Peptide (GHK-Cu)
- Inhibits 5-alpha-reductase locally, promotes collagen synthesis in follicular microenvironment
- 340 Da
- Topical (2% serum daily) or intradermal injection
- 12–18% increased hair density at 24 weeks vs 3% placebo (Dermatologic Surgery, 2024)
- Proven DHT inhibition with lower systemic risk than finasteride. Topical penetration feasible due to small molecular weight
- Valproic Acid Peptide Analogs
- HDAC inhibition extends anagen phase gene expression
- 600–800 Da (analog-dependent)
- Topical application (Phase I only)
- 4.8-week mean anagen extension in Phase I trial, 34 participants (Seoul National University, 2025)
- Early-stage evidence. Dosing protocols not standardized, larger trials needed