The present invention generally relates to the use of cyclic Prolyl Glycine (“cyclic PG” or “cPG”) and analogues and mimetics thereof, as neuroprotective agents for the treatment and or prevention of cognitive impairment and neurological disorders including but not limited to cerebral ischemic or cerebral infarction, status epilepticus, perinatal asphyxia, anoxia, and cerebral trauma, as well as to the treatment and prevention of chronic neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and Huntington's disease, and as anticonvulsants. The present invention also generally provides manufacturing methods to prepare of dosage forms. The present invention further generally relates to the use of cyclic Prolyl Glycine and analogues and mimetics thereof, as neuroprotective and neuro-regenerating agents for the treatment and or prevention of depression and other psychological disorders.