What is Rasayana and what does it do?

Rasayana is the rejuvenation branch of Ayurveda. Charaka states that Rasayana yields longevity, memory, intelligence, freedom from disease, youthfulness, excellent complexion and voice, and optimum strength of body and senses; it nourishes the rasa (nutrient essence) and all subsequent tissues [Charaka Samhita, Chikitsasthana 1, Rasayana Pada]. It works partly by preserving ojas, the essence of all seven dhatus and the seat of immunity and strength [Ashtanga Hridayam, Sutrasthana 11]. Rasayana is central to Karkidaka monsoon therapy. Based on classical texts; consult a doctor for personal advice.