What is a chemical that helps organisms maintain a stable temperature?

Question

What is a chemical that helps organisms maintain a stable temperature?

Answer 1

Water is the governing temperature controller in as much that, when overheated, the body sweats and the evaporation of the sweat causes cooling.

Lack of water causes dehydration and elevation of body temperature as sweat production decreases.

Answer 2

I agree.  H2O does the trick.

Answer 3

H2O