PSA: TB-500 and thymosin beta-4 are not the same thing

preclinical_onlySenior Analyst

Came up in the bpc/tb500 thread and deserves its own post.

Thymosin beta-4 is a 43 amino acid protein, naturally occurring, well characterized, with a real research literature including some human work.

TB-500 is a synthetic fragment of part of that sequence.

They get used interchangeably all the time. They shouldn't be. A fragment is not the parent protein and findings about the parent don't automatically transfer.

Practical version: if you read a summary claiming substantial human evidence for TB-500, follow the citation. Most of the time it goes to a thymosin beta-4 paper. The evidence base is smaller than it looks.

Not saying TB-500 does nothing. Saying the evidence attributed to it is mostly borrowed.

10 replies9 upvotesPeptide Comparisons

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10 replies

  • ShowMeTheDataSenior Analyst

    Chasing citations back is the most useful habit on here and almost nobody does it.

    6 upvotes

  • deload_weekAnalyst

    this should be pinned

    5 upvotes

  • same_tbhSenior Analyst

    ^

    2 upvotes

  • OpenAccessOnlySenior Analyst

    Paywalls are part of why it persists. Can't check the cited paper, so you trust the summary.

    4 upvotes

    • PubmedTabOpenAnalyst

      The abstract usually names the molecule though, and that's free. Worth checking that much before repeating a claim.

      5 upvotes

    • OpenAccessOnlySenior Analyst

      Fair, cheaper than I was implying.

      2 upvotes

  • quick_qSenior Analyst

    so is tb500 just a chunk of tb4?

    2 upvotes

  • rotatorcuff_litAnalyst

    hit this exact thing three times last month, all on sites that looked careful otherwise

    4 upvotes

  • anecdote_flagSenior Analyst

    Deliberate or just inherited sloppiness? My guess is the second.

    3 upvotes

    • preclinical_onlySenior Analyst

      Same read. Has the shape of a copied error.

      2 upvotes

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