This disclosure relates to controlled-release melatonin compositions and related methods. In one embodiment, a controlled-release medicament composition comprises melatonin dispersed in a controlled melatonin release portion comprising a polymer matrix, the polymer matrix adapted to encapsulate the melatonin in a melatonin solubility enhancing pH environment and to maintain the melatonin solubility enhancing pH environment when the composition is located in a melatonin solubility diminishing pH environment for allowing an effective amount of melatonin to be released into the melatonin solubility diminishing pH environment.
