This post from LHCF
mentions that Triethanolamine can be drying. I don't know where she got this info from though:
"Diethanolamine (DEA), Triethanolamine (TEA) — Often used in cosmetics as emulsifiers and/or foaming agents. They can cause allergic reactions, eye irritation and dryness of hair and skin. DEA and TEA are "amines" (ammonia compounds) and can form cancer-causing nitrosamines when they come in contact with nitrates. Toxic if absorbed into the body over a long period of time."