To wash or not to wash your hair every day

I've heard that washing your hair every day can strip it of its natural oils, making it dry and brittle and causing scalp irritation.

- Jancee Dunn

Is that true? And what if I exercise regularly?

Whether you should lather up daily depends on a number of factors, said Dr. Murad Alam, vice-chair of the department of dermatology at the Northwestern University Feinberg School of Medicine. Among them, he said, are your hair's texture, how oily it gets, how processed it is, your lifestyle habits and your age.

Shampoo cleanses your scalp and hair by removing environmental contaminants such as dirt and pollen, as well as dandruff, sweat and haircare products.

It also dissolves sebum, an oily, waxy substance produced by the sebaceous glands near your hair follicles. Sebum keeps your scalp from becoming too dry, said Dr. Rosemarie Ingleton, an assistant clinical professor of dermatology at Mount Sinai Hospital in New York City, and protects the skin from infection.

But if sebum builds up, she said, it can cause problems.

WHEN TO WASH DAILY

Using shampoo every day, Dr. Alam said, can be the right choice for people with oilier scalps where sebum can accumulate, making the hair limp, greasy and possibly smelly.