I read Colgate's complaints and built my own brush: Puneet Nanda

GuruNanda founder-CEO Puneet Nanda said on the podcast that one-star reviews of Colgate Wisp showed users disliked its gelatin sheath, hard bristles and bulk packaging. The gelatin alienated vegans, Jews and Muslims, he noted. His xylitol alternative with Teflon floss is now a top-three seller. He actively worked on producing a better product.