Fluoride is an endocrine chemical

A recent, comprehensive scientific review, published in Endocrine Reviews (2012), lists water fluoridation as endocrine-disrupting chemicals (EDCs), with reported low-dose effects in animals or humans.
The report documented that fluoride inhibits insulin secretion, inhibits parathyroid hormone secretion, and reduces thyroid hormone output. Furthermore, a subsequent study, submitted by a group of international experts assessing EDCs for the World Health Organisation and the United Nations Environment Programme, also listed fluoride as a low-dose EDC.