I will keep my answer simple because of lack of details of the problem. A lot of patients I have seen in your age group were doing extreme dieting and suffering from Malnutrition. Anemia,
Thyroid disorder, Hormonal imbalance etc are main reasons for this problem. And there can be Genetic Pre-Disposition also.
Next Steps
Please take good Nutrition and enroll yourself for an Exercise Program.
Health Tips
Stop applying Chemicals that give Silky look to Hair.