TB-500 Fragment (17-23)

TB-500 Fragment 17-23 is a seven-amino-acid stretch (LKKTETQ) corresponding to the actin-binding region of thymosin beta-4. Researchers have proposed that much of TB-500's tissue-repair activity is concentrated in this short fragment. It is sold strictly for laboratory research as a simplified, lower-cost alternative to full-length TB-500.

TB-500 Fragment 17-23 is the short 'business end' of TB-500. The idea is that researchers can use just this seven-amino-acid stretch — the part that binds actin and drives cell migration — instead of the full 43-amino-acid thymosin beta-4 sequence. It is cheaper to synthesize and easier to handle. Whether it produces the same downstream effects as full-length TB-500 is an open question in the research community.

The LKKTETQ stretch is the primary actin-binding motif within thymosin beta-4. By binding G-actin and supporting actin filament dynamics, it underlies cell migration to injury sites and tissue remodeling — the same mechanism researchers attribute to full TB-500's repair effects.

• •Wound healing in animal models
• •Cell migration assays
• •Cardiac tissue repair
• •Comparative pharmacology with full-length TB-500
• •Hair follicle research

TB-500 Fragment 17-23 is discussed on r/Peptides as a budget alternative to full TB-500. Most experienced users prefer full-length TB-500 for systemic protocols, but the fragment has a niche for users running localized topical or cosmetic research.

“The actin-binding business end of TB-500.”

Sometimes combined with BPC-157 in localized repair protocols, similar to the classic BPC-157 + TB-500 'repair pair.'

TB-500 Fragment 17-23 is the seven-amino-acid actin-binding stretch (LKKTETQ) of thymosin beta-4, studied as a simplified alternative to full-length TB-500 for tissue-repair research.