This invention provides compounds, compositions and methods for treating Autism Spectrum Disorders (ASD) using glycyl-2-methylprolyl-glutamic acid (G-2-MePE) and analogs thereof. Autism Spectrum Disorders include Autism, Autistic Disorder, Asperger Syndrome, Childhood Disintegrative Disorder, Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), Fragile X Syndrome, and Rett Syndrome. Compositions containing compounds include water-soluble formulations, water-in-oil micro-emulsions, water-in-oil coarse emulsions, water-in-oil liquid crystals, nanocapsules, tablets, and orally administered gels. The compounds and compositions of this invention can be administered intravenously, intraventricularly, parenterally, or orally, and can be effective in treating neurodegeneration, promoting neurological function, treating seizure activity and other symptoms of ASD, and can prolong life in animals including human beings having Autism Spectrum Disorders.