Question: are nylon toothbrush bristles biodegradable?
Answer: Verdict: The Environmental Toothbrush bristles are made from Nylon-6, not Nylon-4 as claimed. Nylon-6 is not biodegradable, so the claim that they will biodegrade into soil without pollution is not true. ... Be skeptical of toothbrush manufacturers that claim their bristles are made from Nylon-4 and ask to see the proof.