A reversely thermo-reversible hydrogel composition comprising a water soluble block copolymer comprising at least two blocks of polyethylene oxide and at least one block of polypropylene oxide, and at least one associative gelling adjuvant having water solubility less than 0.5 g/100 ml, preferably less than 0.3 g/100 ml at 20° C., and being capable of forming water soluble inter-molecular complexes with the water soluble block copolymer in water. The hydrogel composition exhibits improved gelling efficiency, enhanced solubility and/or stability for water sparely soluble and insoluble pharmaceutical agents. The hydrogel compositions are useful in a variety of pharmaceutical and cosmetic products and applications, such as esophageal, otic, vaginal, rectal, ophthalmic, treatments of disorders and imperfections of the skin, and treating and/or preventing alopecia and restoring and/or promoting hair growth.