Gaia Guy
Gaia Guy builds its toothbrushes specifically to avoid the nylon trap: the bristles are natural boar (or horsehair), anchored with metal staples and no glue, and the brand says so directly. It publishes a bristle explainer that distinguishes real animal-hair bristles from "plant-based" nylon.
How clear are their specs?
States the bristles are natural boar/horsehair (not nylon), the staples are metal, and no glue is used - and explains the difference from castor nylon in its own content.
