Androgenetic alopecia. And regrow hair.

From the details given your BMI doesn't fall under good category. So its better to check whether the body metabolism goes in proper way. Which includes proper nourishment, digestion and absorption. Causes: Ageing, Pregnancy, Genetic Illness, Some medications such as chemotherapy,  An underactive thyroid gland or any other hormonal disturbance such as PCOS and Diabetes, Malnutrition, Stress, A fever or any severe illness, Autoimmune disorder  etc can cause alopecia or hair fall. Ayurveda believes hair to originate from the “Asthi” or bone tissue, and therefore, to treat hair loss, medicines to strengthen bone should be given orally on a long-term basis. In terms of Dosha involvement, vitiation of Pitha dosha in the body can be the main cause of hair disorders but in some conditions other doshas may also be involved. Irregular bowel movement and constipation can indirectly affect the health of hair. Understanding the causative factor and treating that first is of prime importance. Types: Ayurveda uses three terms to describe the symptoms of hair loss which are Indraluptham, Khalithyam and ruhyam. Indraluptham can be correlated to alopecia areata (circular hair loss). Khalithyam is the general hair fall as a long continuous process and Ruhya is a hair loss condition which affects the entire body. Treatment: Ayurvedic treatment is aimed to treat local and systemic conditions resulting in hair loss, by achieving proper absorption and assimilation of nutrients intaken, immuno modulation, correction of the local scalp conditions and reducing stress. Treatment may involve SHIROABHYANGA, SHIRO DHARA, PRACHANNA, RASAYANA DRUGS etc after proper cleansing treatment. Dosha analysis is important in any ayurvedic treatment. Always consult an ayurvedic practitioner before taking any kind of the ayurvedic medication.

Best to consult a doctor and take medication after proper diagnosis

Have adequate nutrition, good sleep patterns and take plenty of water