any cognitive claim needs a blood brain barrier story first

mechanism_firstSenior Analyst

Prerequisite question for this entire category and it's frequently skipped.

For a peptide to act centrally it has to reach the brain. The blood brain barrier is selective and most peptides don't cross it in meaningful quantity by passive diffusion.

Routes that exist: specific transporters, being small and lipophilic enough to pass, intranasal partially bypassing, or acting peripherally on something that signals centrally. The last one is legitimate and under discussed, a peripheral action with central consequences doesn't require crossing at all.

But a claim of direct central action needs one of these accounted for, and "it raises BDNF in the brain" presupposes it got there. Established physiology, compound specific penetration data is thin for most of what's discussed here.

4 replies7 upvotesCognitive & Neuro

4 replies

  • same_tbhSenior Analyst

    bbb story first. yes

    2 upvotes

  • PKcurveSenior Analyst

    The intranasal point is why that route shows up so much here. Partial bypass rather than full, and the fraction reaching the CNS is generally small and variable.

    4 upvotes

  • quick_qSenior Analyst

    so intranasal doesnt fully bypass it?

    2 upvotes

  • nootropic_sideSenior Analyst

    explains the delivery format for basically everything in this space, never connected those

    3 upvotes

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