Compare prices and buy TB-500 Thymosin Beta-4 from 43 research peptide vendors - also called suppliers or sources. Updated daily.
The full 43-amino-acid peptide Thymosin beta-4 (Tbeta4, CAS 77591-33-4), a ubiquitous G-actin-sequestering protein present in nearly all human cells. By binding actin monomers it regulates cytoskeletal assembly, and in laboratory models it promotes cell migration and angiogenesis. It has been tested in placebo-controlled trials, furthest as an eye drop for dry eye disease. Commonly marketed as "TB-500" by research-peptide vendors but not FDA-approved.
For research purposes only. Not medical advice.
This row is full-length thymosin beta-4: a 43-amino-acid protein, CAS 77591-33-4, present in nearly all human cells, where it binds monomeric G-actin and so regulates cytoskeletal assembly, cell migration and angiogenesis. Vendors label it "TB-500," "TB-4 Full Chain," "TB-500 (TB4 - long chain)" and "Thymosin Beta-4."
It is not the only compound sold under that name. TB-500 Frag 17-23 is a seven-amino-acid fragment of this protein (N-acetyl-Leu-Lys-Lys-Thr-Glu-Thr-Gln, CAS 885340-08-9) carrying the actin-binding motif at residues 17-23. The label "TB-500" originally referred to that fragment and migrated to the full chain as vendors moved to it, which is why one name now covers both. Reference sources have not settled it either: PubChem files "TB500" under the fragment, while the full protein sits under its own International Nonproprietary Name, Timbetasin.
PeptideScouter keeps the two as separate rows because a price per milligram on a 43-residue protein is not comparable to one on a seven-residue fragment. The CAS number or the molecular formula on a certificate of analysis is the only reliable way to tell which one a listing is selling.
In July 2026 the Pharmacy Compounding Advisory Committee voted to recommend adding "TB-500," evaluated for wound healing, to the 503A bulk drug substances list. That vote was about the fragment, not this row. FDA's briefing document defines the nominated substance as the N-acetylated heptapeptide of residues 17-23, in free base and acetate forms. Full-length thymosin beta-4 was not before the committee.
The distinction was part of the argument rather than incidental to it. FDA's reviewers objected that the TB-500 forms are not physically and chemically well characterized, citing inconsistent naming that follows no INN, USAN or IUPAC standard, and recommended against adding the substance. The committee voted the other way, as it did on five of the other six substances heard that week.
Full-length thymosin beta-4 is in none of the three categories of FDA's 503A nominations list (May 2026 update). Nor was it ever in Category 2: the entry the FDA added on September 29, 2023 and removed by its April 15, 2026 notice is "thymosin beta-4, fragment (LKKTETQ)," the seven-residue TB-500. In any case a PCAC recommendation is advisory: the list changes only through notice-and-comment rulemaking. Our writeup of the July 2026 PCAC vote covers all seven substances, including BPC-157, with which TB-500 is frequently co-marketed.
Thymosin beta-4 has a clinical history the fragment lacks. RegeneRx Biopharmaceuticals developed synthetic full-length peptide under several designations: RGN-259 (a preservative-free ophthalmic solution taken through the ARISE trials in dry eye disease), RGN-137 (a topical gel studied in epidermolysis bullosa) and RGN-352 (an injectable formulation whose Phase 2 heart-attack trial was withdrawn before it began). Beijing Northland Biotech has completed two Phase 2 trials of its recombinant version, NL005, in acute myocardial infarction. None produced an approval, and thymosin beta-4 is not approved by the FDA for any indication.
It also appears as an unspecified "TB-500" component in multi-peptide blends including Wolverine, GLOW and KLOW. PeptideScouter computes a per-milligram price for this row's vials and verifies identity against its molecular formula (C212H350N56O78S, CAS 77591-33-4). Material sold by peptide vendors, at either chain length, is offered for laboratory research use only and not for human consumption.
No. FDA's briefing document for the July 2026 Pharmacy Compounding Advisory Committee meeting defines the nominated substance as the N-acetylated seven-amino-acid fragment of thymosin beta-4, residues 17-23, CAS 885340-08-9, in free base and acetate forms. That is the separate TB-500 Frag 17-23 row on this site. Full-length thymosin beta-4, CAS 77591-33-4, was not on the agenda. The committee's July 2026 vote applies to the fragment, and is advisory rather than binding in either case.
They are two different substances sold under one name. Thymosin beta-4 is the full 43-amino-acid protein, CAS 77591-33-4, also known by the International Nonproprietary Name Timbetasin. TB-500 Frag 17-23 is a seven-amino-acid fragment of it, N-acetyl-Leu-Lys-Lys-Thr-Glu-Thr-Gln, CAS 885340-08-9, containing the actin-binding motif. The name TB-500 originally meant the fragment and later attached to the full chain as well, so a product labelled TB-500 could be either. Check the CAS number or molecular formula on the certificate of analysis. PeptideScouter lists them separately because a per-milligram price on one is not comparable to the other.
TB-500 Thymosin Beta-4 is sold by 43 research peptide vendors indexed on PeptideScouter, with 78 tracked listings compared per vendor in the table above. Pricing is normalized and refreshed daily.
41 of the 43 indexed vendors currently have TB-500 Thymosin Beta-4 in stock. The comparison table marks out-of-stock listings, and stock state is refreshed daily.
Studz Peptides currently lists TB-500 Thymosin Beta-4 at $2.75/mg, the lowest listed price across 43 tracked research peptide vendors. With current vendor discount codes applied, the lowest effective price is $2.48/mg.
Discount codes are issued per vendor rather than per peptide, so any code applies across that vendor's whole catalog. All 43 vendors listing TB-500 Thymosin Beta-4 publish a PeptideScouter code, worth 5% to 50% off. Applied, the lowest effective price falls from $2.75/mg listed to $2.48/mg at Studz Peptides. Each vendor's code is shown beside its price in the table above.
TB-500 Thymosin Beta-4 ranges from $2.75/mg to $13.90/mg across 78 listings from 43 research peptide vendors, normalized to USD per milligram and refreshed daily.
43 research peptide vendors currently list TB-500 Thymosin Beta-4 on PeptideScouter, with 41 in stock right now. We track 78 listings across size and kit variants.
TB-500 Thymosin Beta-4's CAS Registry Number is 77591-33-4. It is also sold as TB-4 Full Chain, TB-500(TB4), TB-500.
