This is a summary of a few posts from Roundtable. It’s a bit complicated so I tried to break it down in understandable pieces.
TB-500 and TB4 are often used interchangeably by vendors to mean the same peptide but they are distinctly different.
When Jano tests the peptide, the report will either read as TB-500 (TB4) or TB-500 (889Da).
CAS 77591-33-4: Thymosin Beta-4 (TB4) is a naturally occuring peptide in the body, primarily involved in tissue repair and regeneration. It consists of 43 amino acids.
TB-500 refers to a specific fragment of TB4 consisting of amino acids 17-23 (TB4 17-23 frag), particularly effective for wound healing, angiogenesis, and tissue repair.
There are (2) versions of TB4 17-23 frag:
CAS 885340-08-9: This refers to TB-500, a synthetic peptide comprising the amino acid sequence LKKTETQ with an N-acetylated leucine at the N-terminus. Its molecular formula is C₃₈H₆₈N₁₀O₁₄, and it has a molecular weight of 889.01 g/mol - what Jano refers to as TB-500 (889 Da).
CAS 476014-70-7: This refers to fequesetide, also known as TB4 Fragment 17-23, which includes the same amino acid sequence LKKTETQ but without the N-acetylation. Its molecular formula is C₃₆H₆₆N₁₀O₁₃, and it has a molecular weight of 846.97 g/mol - I have not come across this.
The primary distinction between these two peptides lies in the N-acetylation of the leucine residue in TB-500, which is absent in fequesetide. This modification can influence the peptide's stability, bioavailability, and biological activity (improves it). Therefore, while both peptides share the same core sequence, the N-acetylation in TB-500 differentiates it from fequesetide.
So TB-500 is the TB4 frag you want. When sourcing, be sure to verify the CAS number because much of what is sold as TB-500 is really the full sequence TB4 (CAS 77591-33-4).
Why does this matter? Because it takes a much smaller dose of TB-500 (889Da) to equal the potency of amino acids 17-23 in 1mg of the full sequence TB4. 1mg of TB4 = 0.18mg of TB-500 (889Da).
What I don’t know is if the GLOW blend was intended to be formulated with TB-500 (TB4) or TB-500 (889Da) and I have no knowledge of the impact of the increased potency of TB-500 (889Da) if the former was the intent.
