GHK (Glycine-Histidine-Lysine Tripeptide) vs Thymosin Beta-4 Fragment (TB4-Frag 17-23)
A neutral, side-by-side comparison of two healing & recovery peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
GHK (Glycine-Histidine-Lysine Tripeptide)
The free tripeptide component of GHK-Cu before copper complexation. GHK naturally occurs in human plasma, saliva, and urine and promotes wound healing, collagen synthesis, and anti-inflammatory activity. While it readily chelates copper to form GHK-Cu in vivo, research distinguishes the independent effects of free GHK from the copper-complexed form on gene expression and tissue remodeling.
Full profileThymosin Beta-4 Fragment (TB4-Frag 17-23)
The heptapeptide fragment (amino acids 17–23) of full thymosin beta-4, sequence Ac-LKKTETQ. This sequence is the active actin-binding domain responsible for TB-500's tissue repair properties. Shorter molecular weight than TB-500 enables more targeted delivery while retaining identical mechanism of action on G-actin regulation and tissue repair signaling.
Full profile| GHK (Glycine-Histidine-Lysine Tripeptide) | Thymosin Beta-4 Fragment (TB4-Frag 17-23) | |
|---|---|---|
| Category | Healing & Recovery | Healing & Recovery |
| Also known as | GHK tripeptide, Gly-His-Lys, copper chelating tripeptide, GHK free tripeptide | TB4 fragment 17-23, TB-500 active peptide, LKKTETQ, thymosin beta-4 fragment, Ac-LKKTETQ |
| Evidence | Research-stage | Research-stage |
| Dosing range | 0.5mg–2mg mg, Daily or every other day (topical or SC) | 250mcg–1mg mcg–mg, 2–3x weekly |
| Administration | Subcutaneous injection, Topical (cream/serum) | Subcutaneous injection, Intramuscular injection |
| Key side effects | Minimal reported side effects, Mild injection site irritation, Rare topical sensitization, No significant systemic effects at research doses | Injection site irritation, Mild fatigue (transient), Potential headache, Generally well-tolerated in research applications |
| Cited sources | 2 references | 2 references |
Key differences
- Administration: GHK (Glycine-Histidine-Lysine Tripeptide) — Subcutaneous injection, Topical (cream/serum); Thymosin Beta-4 Fragment (TB4-Frag 17-23) — Subcutaneous injection, Intramuscular injection.
- Dosing units differ: GHK (Glycine-Histidine-Lysine Tripeptide) is dosed in mg, Thymosin Beta-4 Fragment (TB4-Frag 17-23) in mcg–mg — they operate at different scales.
- Frequency: GHK (Glycine-Histidine-Lysine Tripeptide) is typically Daily or every other day (topical or SC); Thymosin Beta-4 Fragment (TB4-Frag 17-23) is 2–3x weekly.
How each works
GHK (Glycine-Histidine-Lysine Tripeptide)
Free GHK directly upregulates collagen, elastin, and laminin synthesis in fibroblasts through TGF-β pathway activation and metalloproteinase modulation. Loren Pickart's decades of research identified GHK as a potent tissue remodeling signal whose plasma concentrations decline with age. At physiologic concentrations, GHK resets approximately 31% of dysregulated gene expression associated with aging back toward a younger phenotype.
Thymosin Beta-4 Fragment (TB4-Frag 17-23)
The LKKTETQ sequence was identified in 1994 as the minimum active fragment of thymosin beta-4 responsible for its actin-sequestering and tissue repair activity. This heptapeptide competes with actin monomer binding proteins, promoting cell migration, angiogenesis, and wound healing. Studies confirm it recapitulates the key bioactivity of full TB4 in cell migration and collagen deposition assays.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.