The first toothbrushes hit the U.S. in the mid-1800s, made from wood and boar bristles. But in the 1930s, when plastic became widely available, brands started mass producing cheap, disposable brushes. When curbside recycling became mainstream 50 years ago, the toothbrush was excluded: The shape and mix of plastic used for toothbrushes means they can’t be processed by municipal recycling centers. Colgate has partnered with recycling platform TerraCycle to collect and recycle toothbrushes, but in the last decade has managed to recycle only 5 million, less than 1% of the brushes it manufactured during this period.

The convenience of plastic has come at an enormous cost to the planet: Some 9.1 billion tons of plastic have been produced since the material was first mass produced in the 1950s, and 91% of it isn’t recycled. The material doesn’t biodegrade, so it will remain in our environment for hundreds of years, breaking into tiny particles that can get swept into the ocean and end up in our food chain. Consumers are waking up to how problematic plastic is, and this growing aversion presents a threat to consumer goods conglomerates like Colgate’s parent company, Colgate-Palmolive, which continues to rely on plastic for the majority of its products.

Even if individuals wanted to lower their plastic footprint, there haven’t been many sustainable options for packaged goods. But over the past five years, startups have begun developing personal care products that don’t use as much plastic. By Humankind makes refillable deodorant, dental floss, and dissolvable mouthwash tablets. Bite makes compostable bamboo toothbrushes and toothpaste bits that foam up in your mouth. The Keep is most similar to a brush designed by startup Goodwell that hit the market in 2016, which also has a metal base and replaceable head, although its handle is made from recycled aluminum and its head is made from a biodegradable bioplastic. (Goodwell costs more than twice the price of Keep.) While these brands have found an audience of eco-friendly customers willing to change their behaviors, they make up a tiny fraction of the market.”