A composition for administration to a subject, such as oral administration to a subject, for example, has been provided. Such a composition may comprise at least one magnesium-counter ion compound. A magnesium-counter ion composition described herein may be useful for any of a variety of applications provided herein, such as maintaining, enhancing, and/or improving health, nutrition, and/or another condition of a subject, and/or cognitive, learning, and/or memory function. A magnesium-counter ion composition provided herein may be useful for administration to a subject presenting magnesium deficiency, mild cognitive impairment, Alzheimer's disease, attention deficit hyperactivity disorder, ALS, Parkinson's disease, diabetes, migraine, anxiety disorder, mood disorder, and/or hypertension. A kit, method, and other associated technology are also provided.