> ## Content Index
> Fetch the complete content index at: https://curo.ghost.io/llms.txt
> Use this file to discover other available public pages before exploring further.

# TB-500 Peptide: Matching a Listing Name to FDA, PubChem and WADA Records
- URL: https://curo.ghost.io/tb-500-peptide-name-records/
- Published: 2026-10-15T19:54:53.000Z
- Updated: 2026-10-15T19:54:53.000Z
- Author: Romio
- Tags: Peptide research

TB-500 peptide listings rarely agree on what the name covers. This note walks through the public records that tie the name to a specific molecule and shows what each record confirms. The [TB-500 peptide guide](https://sites.google.com/view/tb-500/?ref=curo.ghost.io) gives the same material question by question.

### Step 1: the sequence

The reference sequence is N-acetyl-Leu-Lys-Lys-Thr-Glu-Thr-Gln, seven amino acids. PubChem holds it as CID 62707662, with the formula C38H68N10O14 and a molecular weight of 889.0 g/mol. FDA's Substance Registration System holds the same molecule as UNII QHK6Z47GTG, preferred name TB-500, and lists the N-terminal acetylated 17-23 fragment of thymosin beta 4 among its mappings. Sources: [PubChem record for TB-500](https://pubchem.ncbi.nlm.nih.gov/compound/62707662?ref=curo.ghost.io) and [FDA UNII record for TB-500](https://precision.fda.gov/uniisearch/srs/unii/QHK6Z47GTG?ref=curo.ghost.io).

### Step 2: the neighbors

Two other records sit close to TB-500 and are easy to confuse with it. Thymosin beta-4, the protein from which TB-500 was copied, has its own UNII and 43 amino acids. The acetate form of TB-500 appears in FDA's 2026 briefing document with a different formula and weight. The list keeps them apart.

- PubChem CID 62707662: TB-500\. C38H68N10O14, 889.0 g/mol.
- FDA UNII QHK6Z47GTG: TB-500\. CAS 885340-08-9.
- FDA UNII 549LM7U24W: thymosin beta-4\. 43 amino acids.
- FDA briefing, Table 1: TB-500 acetate. C38H68N10O14·CH3COOH, 949.1 g/mol.

Sources: [PubChem](https://pubchem.ncbi.nlm.nih.gov/compound/62707662?ref=curo.ghost.io), [FDA UNII for TB-500](https://precision.fda.gov/uniisearch/srs/unii/QHK6Z47GTG?ref=curo.ghost.io), [FDA UNII for thymosin beta-4](https://precision.fda.gov/uniisearch/srs/unii/549LM7U24W?ref=curo.ghost.io) and the [FDA briefing document](https://www.fda.gov/media/193349/download?ref=curo.ghost.io).

### Step 3: the printed CAS number

A CAS number looks like proof of identity, and FDA's briefing shows why it is not always one. A footnote to its comparison table states: "On several suppliers' websites, the CAS number for TB-500 (free base) (885340-08-9) is used for TB-500 Acetate." A listing that pairs that number with the acetate's weight gives two records that do not match.

### Step 4: the sport list

The WADA Prohibited List names "Thymosin-ß4 and its derivatives e.g. TB-500" in section S2.3\. The entry names a substance family and gives no sequence, so the entry alone does not say which molecule a listing contains. WADA's research page for a 2013 TB-500 project records that the original product was presented without an amino acid sequence or molecular weight. Sources: [WADA 2026 Prohibited List](https://www.wada-ama.org/sites/default/files/2025-09/2026list%5Fen%5Ffinal%5Fclean%5Fseptember%5F2025.pdf?ref=curo.ghost.io) and [WADA project page](https://www.wada-ama.org/en/resources/scientific-research/investigation-vitroex-vivo-tb-500-metabolism-synthesis-relevant?ref=curo.ghost.io).

### Step 5: the lot

Records name molecules, and a lot report describes a vial. FDA's briefing reviewed a representative public certificate for TB-500 (free base) and reported that it covered appearance, identity and purity, while assay, impurities, bacterial endotoxins and aggregates were not tested or controlled. The [TB-500 for sale listing checks](https://sites.google.com/view/tb-500/tb-500-for-sale?ref=curo.ghost.io) go through the report fields. One supplier defines its fields on [Curo's testing page](https://curo.you/u/google-sites?to=%2Ftesting&utm%5Fsource=ghost&utm%5Fmedium=referral&utm%5Fcampaign=tb%5F500&utm%5Fcontent=ghost%5Ftesting), publishes lot reports in [Curo's lot-certificate library](https://curo.you/u/google-sites?to=%2Fcoa&utm%5Fsource=ghost&utm%5Fmedium=referral&utm%5Fcampaign=tb%5F500&utm%5Fcontent=ghost%5Fcoa) and lists the 5 mg material as [Curo's TB-500 5mg listing](https://curo.you/u/google-sites?to=%2Fproducts%2Ftb-500-5mg&utm%5Fsource=ghost&utm%5Fmedium=referral&utm%5Fcampaign=tb%5F500&utm%5Fcontent=ghost%5Fproduct).

Sources checked October 15, 2026\. Reference information for laboratory research.