A synthetic fragment of thymosin beta-4; the full protein has small eye-drop and wound trials, while the fragment itself has no published human data.
BPC-157 has about 30 people in small uncontrolled reports. TB-500 has none yet, though full-length thymosin beta-4 has randomised trials, mostly in eyes. Neither has a controlled injury trial.
One rat study has tested the pair head to head, and the combination did no better than either peptide alone. There are no controlled human data.
Thymosin beta-4 has been through randomised human trials, mostly as eye drops, with a clear win in neurotrophic keratopathy and flat results in the two large dry-eye studies. TB-500 is the seven-amino-acid fragment built on the actin-binding motif that started this work, and its first human trial began recruiting in February 2026.
Neither primary outcome improved in the larger of two published phase 2 trials. Some secondary measures did, and the drops looked safe for 28 days.
