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Hairmetry

Encyclopedia

Every molecule that touches your hair

From proven medicines to kitchen-cupboard oils, with the studies behind each one.

5 entries

B

  • supplement

    Biotin

    A B vitamin that restores hair only in the rare people who are deficient, and that can scramble thyroid and heart blood tests at the doses sold for hair.

M

R

  • pathway modulator

    Rapamycin (sirolimus)

    The longevity-world favourite is a hair paradox: one 2019 mouse study found it starts hair growth, while older and 2013 mouse work found it does not or even delays it, and mTOR-pathway cancer drugs can cause hair loss.

S

  • protein or peptide

    SCUBE3

    A protein released by the hair follicle's command centre only while hair is growing; injecting it into mouse skin was enough to start new growth, with no human data yet.

  • supplement

    Spermidine

    A natural compound sold as a longevity supplement lengthened human hair follicles grown in a dish at tiny concentrations, but nobody has shown it grows hair on a head.