TB-500 Fragment
PreclinicalThe actin-binding engine of TB-500 sold as a substitute at a sixth of the cost, where the engine works but the missing parts matter.
What it is
TB-500 fragment is a seven-amino-acid sliver of the larger peptide thymosin beta-4, matching the region of that protein that grabs onto actin, a building block of every cell's internal skeleton. The rest of the parent molecule is stripped away, leaving a cheaper-to-make research chemical.
How it works
The fragment genuinely keeps the capability to bind actin, the protein that gives cells their shape and lets them move. That binding is how the full thymosin beta-4 is thought to support tissue repair and recovery. The question nobody has answered is whether actin binding alone reproduces all the healing effects, which likely also depend on how the cell takes the protein up and other wider signals.
What people report
- ✦Costs about six times less to make than full thymosin beta-4, which shows up in the vial price
- ✦A meaningful minority of community users report results comparable to the full peptide
- ✦Minimal side-effect profile, like its parent
- ✦The actin-binding core is real, characterized biochemistry
Typical use
Community protocols mirror full TB-500, typically a few injections per week over several weeks, but no validating trials exist for the fragment specifically.
Dosing reference
No approved dose. Community users often run it like the parent peptide, but the fragment has no clinical study backing equal outcomes. Verify any product and dosing, especially that you are getting the fragment rather than something else.
Reference only — not a recommendation. Verify via primary sources.
Watch for
The scientific literature on this family is overwhelmingly about the full peptide, not this fragment. Community reports are bimodal and tend to favor the full peptide when people have tried both at matched doses. The fragment is real biology riding on extrapolation.
Notes
For users priced out of full TB-500, the fragment is the obvious move, but the evidence and track record still favor the full peptide.
Educational content — not medical advice.