BPC-157 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.
BPC-157
BPC-157 is a synthetic 15-amino-acid peptide derived from a protective protein found in human gastric juice. It has been extensively studied in animal models for tissue repair, gastroprotection, and tendon/ligament/muscle healing. Important: essentially all efficacy data are preclinical (rodent), there are no completed published human efficacy trials, and it is prohibited in sport by WADA.
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| BPC-157 | Thymosin Beta-4 Fragment (TB4-Frag 17-23) | |
|---|---|---|
| Category | Healing & Recovery | Healing & Recovery |
| Also known as | Body Protection Compound 157, PL 14736, Pentadecapeptide BPC 157 | TB4 fragment 17-23, TB-500 active peptide, LKKTETQ, thymosin beta-4 fragment, Ac-LKKTETQ |
| Evidence | Preclinical only | Research-stage |
| Dosing range | 200mcg–1000mcg mcg, once or twice daily | 250mcg–1mg mcg–mg, 2–3x weekly |
| Administration | Subcutaneous injection (most common), Intramuscular injection, Oral (reduced bioavailability — used for gut-specific protocols) | Subcutaneous injection, Intramuscular injection |
| Key side effects | Nausea (rare, typically at higher doses), Dizziness / lightheadedness shortly after injection (uncommon, anecdotal), Injection site redness or irritation, Human safety profile is not established — no controlled human trials | Injection site irritation, Mild fatigue (transient), Potential headache, Generally well-tolerated in research applications |
| Cited sources | 6 references | 2 references |
Key differences
- Evidence level differs: BPC-157 is preclinical only, while Thymosin Beta-4 Fragment (TB4-Frag 17-23) is research-stage.
- Administration: BPC-157 — Subcutaneous injection (most common), Intramuscular injection, Oral (reduced bioavailability — used for gut-specific protocols); Thymosin Beta-4 Fragment (TB4-Frag 17-23) — Subcutaneous injection, Intramuscular injection.
- Dosing units differ: BPC-157 is dosed in mcg, Thymosin Beta-4 Fragment (TB4-Frag 17-23) in mcg–mg — they operate at different scales.
- Frequency: BPC-157 is typically once or twice daily; Thymosin Beta-4 Fragment (TB4-Frag 17-23) is 2–3x weekly.
- Research depth: this profile cites 6 sources for BPC-157 vs 2 for Thymosin Beta-4 Fragment (TB4-Frag 17-23).
How each works
BPC-157
Preclinical rodent and in-vitro studies — predominantly from the Sikiric group in Zagreb, with mechanistic angiogenesis work from Pang's group in Taiwan — report accelerated healing of tendon, ligament, muscle, and gut tissue. Proposed mechanisms include modulation of the nitric oxide (NO) system, promotion of angiogenesis via the VEGFR2–Akt–eNOS pathway, upregulation of growth factor signaling, and effects along the gut–brain axis. Despite a large and internally consistent animal literature, BPC-157 has no completed human clinical efficacy trials and is an unapproved drug.
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.