bpc-157 vs tb-500

updated October 25, 2026

bpc-157 (tier A) vs tb-500 (tier A): what each is, why each got its grade, half-life and source counts side by side.

the difference

checked October 25, 2026

tb-500 names N-acetyl-LKKTETQ, a seven-amino-acid fragment of thymosin beta-4, and FDA's July 2026 review identified no clinical studies or human exposure data for tb-500.

• FDA presentations, Pharmacy Compounding Advisory Committee, July 23, 2026 (BPC-157, KPV, TB-500)
• Esposito S et al. Drug Test Anal 2012 (PMID 22962027)

human trials of thymosin beta-4, including phase 3 eye-drop trials, tested the full-length protein.

• Sosne G. Expert Opin Biol Ther 2018 (PMID 30063853)
• Sosne G, Ousler GW. Clin Ophthalmol 2015 (PMID 26056426)
• ClinicalTrials.gov NCT03937882, ARISE-3
• ClinicalTrials.gov NCT02600429, SEER-1

in July 2026, FDA proposed that neither bpc-157 nor tb-500 be added to the 503A bulks list for pharmacy compounding, and its review says neither is a component of an FDA-approved drug. FDA's advisory committee then voted on both; news reports put the vote on each at 8-6-1 in favor of adding it, and the committee's recommendations are non-binding.

• FDA presentations, Pharmacy Compounding Advisory Committee, July 23, 2026 (BPC-157, KPV, TB-500)
• FDA meeting page, Pharmacy Compounding Advisory Committee, July 23-24, 2026

bpc-157 · tier A

the contested repair peptide. strong animal data, thin human trials, huge community gravity.

tier rationale

A-tier because the preclinical evidence is extraordinary and the community signal is persistent. Not S-tier because drug-grade human evidence does not exist, long-term human safety is not characterized, and the single-lab concentration matters. If independent controlled trials ever hold up, the tier can move. Until then, A is the ceiling.

tb-500 · tier A

names a 7-amino-acid fragment of thymosin beta-4, but the vial you buy is a coin toss: fragment, full-length protein, or mislabeled. the COA mass is the only thing that knows.

tier rationale

not actually thymosin β-4. it's a 7-amino-acid fragment of it, the actin-binding LKKTETQ sequence at positions 17-23. sold in the 2000s through the Australian equine veterinary market before crossing into human gray-market use. now widely discussed as BPC-157's companion in the "wolverine stack." the name refers to the actin-binding LKKTETQ fragment, but vendor vials frequently contain the full 43-amino-acid protein instead, and only the COA mass resolves which. either way the grade is the same. the preclinical base across skin, cornea, heart, and brain is large and reproducible, which keeps it above the lower tiers. but the human program has missed its pivotal phase 3 trials (SEER-1, ARISE-3, and SEER-3 in june 2026) and nothing is approved anywhere, which keeps it below S. A-tier: real biology, unfinished proof.

at a glance

reptides grades the research record and cites the literature behind every call. research reference only; not medical advice.