A scalable vitamin composition unit dosage adapted to treat a fat-soluble vitamin deficiency in a subject is provided herein, the unit dosage consisting essentially of vitamin D, vitamin E, vitamin K, and vitamin A, wherein the unit dosage is substantially free of additional vitamins and wherein the unit dosage is scalable based on the weight, age, and condition of a subject without inducing toxic effects. Also provided are methods of treating a fat-soluble vitamin deficiency in a subject in need thereof by administering to the subject an effective amount of a unit dosage as described herein.