Functional foods are those wholesome fortified, enriched or enhanced foods that provide health benefits beyond the provision of essential nutrients when they are consumed as part of the diet. Scientists, today are identifying physiologically active components of food that can reduce the risks of the variety of diseases and optimize health. The consumer self-care phenomenon has increased and hence there is a rapid growth in the market for health and wellness products. A functional food containing pink guava, whey and walnut were developed. The formulation was evaluated for its health benefits like antioxidant, probiotic, immune modulatory and antimicrobial activity. The formulation was freeze-dried for stability. Standardization was done using UV spectroscopy and high-performance liquid chromatography methods. The formulation showed distinct probiotic and antimicrobial activity. Immunomodulatory activity was evaluated using animal models. The formulation also showed significant values for protein, total fat content, vitamin C, pectin, and energy value. The product is a novel, holistic and economical combination and thus it can be used as the rejuvenator for an efficient, effective and healthy lifestyle.