What it is: An antibacterial and antifungal agent found in some antibacterial soaps, cleaners and toothpastes.
How it might harm: Studies on triclosan are limited to animals, but in mice and frogs it’s been shown to affect hormone function. For example, one 2012 study at UC Davis exposed mice and fish to small amounts of triclosan – similar to what humans would be exposed to through products – and found the presence of the chemical reduced muscular strength. Another study by Caren Helbing, a professor of biochemistry at the University of Victoria, found tadpoles exposed to triclosan developed into frogs faster than those not exposed to the chemical.
How to avoid it: Because it only comes under one name, this one is easy to spot on the label.