Different origins, overlapping research interest
BPC-157 is a synthetic peptide fragment derived from a protein found in gastric juice, studied in animal models largely for its effects on tissue repair and the gut-brain axis. TB-500 is a synthetic version of a fragment of Thymosin Beta-4, a naturally occurring protein studied for its role in cell migration and actin regulation, which is relevant to wound healing and angiogenesis.
They're frequently discussed together because both appear in recovery-focused research and are sometimes studied in combination, but they're structurally unrelated compounds with different proposed mechanisms.
Why vendors sell them as a blend
Several vendors in our comparison (see the BPC-157 + TB-500 listing) sell a pre-mixed blend rather than two separate vials. This is a convenience/packaging choice on the vendor's part — it doesn't change what either compound is individually, and the same verification questions apply to a blend as to either compound alone: is there a COA, and does it cover this specific blended batch or just the individual ingredients separately?
Comparing prices between them
Because the two are priced differently across vendors — TB-500 tends to run somewhat higher per mg than BPC-157 in our data — it's worth checking each one's own comparison page rather than assuming a vendor that's cheap on one is cheap on both.
For research use only. This guide is general background information, not medical or dosing advice.