When your hair doesn't get enough moisture, it becomes dry and dull. Dry hair affects men and women at any age, but it is more likely to develop as we age. Our hair consists of three layers. Healthy hair contains natural oils in the outer layer that protect the other two layers. Dry hair doesn't have the same protective oils. This makes them appear frizzy and lifeless.
Health problems can affect hair's ability to keep moisture. Anorexia nervosa, for example, causes dry and brittle hair, along with other complications. Hypoparathyroidism can also result in dry hair due to its decrease of calcium in the body.
If your hair is quite dry and it doesn't get better with changes in hair products, make an appointment with a doctor. They can refer you to a specialist who will find the problem. They can also refer you to a dermatologist who specializes in hair conditions.