Skip to reading Consultation desk Questioning claims about a protein fragment Start desk Research notes Check · The evidence # What did the studies actually test? The first question is not whether a paper sounds hopeful. It is whether the paper studied the same thing being offered to you. A path for your questions Which substance? Which people or animals? Which result? A paper becomes more useful when these questions have clear answers. Read this first ## The human-study gap comes first. In the FDA review checked in September 2026, no published study had given TB-500 to people. The Food and Drug Administration, or FDA, found no published account of giving it to a patient either. Proteins are chains of small parts that do jobs in the body, such as helping cells move. Thymosin beta-4 is a protein found in the body; studies in people used its full chain, which is different from TB-500. Chapter notes FDA’s search for human evidence ## What hopeful claims rest on ### Cells and mice do not answer the human question. FDA recorded online claims about healing and recovery, but found no TB-500 study in people to support them. In a 2003 mouse study, skin wounds closed better with full thymosin beta-4 and a small piece of it. The piece used on the mice lacked the small extra chemical piece attached to TB-500, so it was a different substance. For TB-500 itself, FDA found no animal study testing wound healing as of the September 2026 review. In a lab test reviewed by FDA, researchers scratched a gap in a layer of cells grown in a dish. Adding TB-500 did not make the cells close that gap faster. That TB-500 test was on cells in a dish, not an injury in a person. It does not prove that TB-500 can never work, but it did not support the healing claim. Chapter notes The mouse wound study The mice received a piece without TB-500’s added chemical piece. FDA’s reading of the cell and animal work ## Human research on the full protein ### Eye-drop results were mixed. The human eye-drop trials used full thymosin beta-4, not TB-500. In a 2015 study of 72 people with dry eyes, full thymosin beta-4 drops did not clearly beat drops without that protein on either main check. The main checks for the thymosin beta-4 drops were eye discomfort and signs of surface damage seen with a coloured liquid on the eye. Some smaller checks in that 2015 thymosin beta-4 trial improved, but the main goals were not met. In a later study of 700 people, the average results for these checks were about the same with full thymosin beta-4 drops and drops without that protein. As of September 2026, the checked results for that larger thymosin beta-4 study lacked a calculation showing whether any difference was more than chance. These findings concern the full protein used as eye drops, not TB-500 for an injury. Chapter notes The smaller eye-drop trial The larger trial’s posted results ## When a trial listing looks convincing ### Read what the study summary says. At the September 2026 check, the only TB-500 record found on ClinicalTrials.gov called itself a fictional example in its own summary. ClinicalTrials.gov is the US government’s website for listing studies in people. That entry cannot serve as evidence of a real TB-500 trial. Ask for a published paper, the exact substance and the actual result. A trial listing alone is not that answer. Chapter notes The trial record and its own summary Back a desk US rules Next learning step Finding care Use these desks to sort out care questions; this guide shares information, offers no clinic care and sells no medicines. All desks Word help Read as text Start Care Costs Cautions Words