Your hair can get dry because your scalp doesn’t make enough oil to moisturize your hair, or your hair lets moisture escape.
Your scalp isn’t making enough moisture. Hair has no natural lubrication. It relies on oils made in the hair root to keep your hair moisturized and looking lustrous.
Sometimes, hair doesn’t make enough oil, which leads to dry hair. (Likewise, roots in overdrive lead to oily and greasy hair.) As you age, your hair naturally makes less oil. Since the roots are under your skin, dry scalp goes along with dry hair. Dry scalp peels and sheds, leading to dandruff flakes on your shoulders.
The moisture you have is escaping. Each strand of healthy hair has a protective layer called the cuticle. Just as shingles shield your home from rain and sun damage, the cuticle shields your hair from heat and sun damage. In a healthy cuticle, the layers lie tightly together and keep moisture in. When a cuticle’s layers separate and peel away from hair, its ability to hold moisture is compromised - some oil escapes.
Several things can damage your hair:
- Over-washing or using a harsh shampoo strips away your hair's natural oils
- Blow drying your hair too often -- especially when you apply alcohol-based styling products first
- Using heated hair straighteners or curling irons
- Exposing your hair to lots of sun, wind, or dry air
- Applying chemical treatments, including dyes, perms, and relaxers
- Wash your hair less often. You may be able to get away with washing once or twice a week instead of every day (many people can). As a bonus, when you shampoo less frequently, you won't need to blow dry and heat-style it as much.
- Use a mild shampoo made specifically to help dry hair because it will have fewer drying detergents.
- Use hair products that don’t have alcohol because it is drying.
- Follow the shampoo with a moisturizing conditioner. It will keep cuticles lying flat so they hold in natural oils.
- Massage jojoba oil or coconut oil into your scalp to replenish moisture.
After you've tried these techniques, if your hair is still dry and brittle, ask your stylist about a professional deep conditioning treatment. If your dry hair occurs with fatigue, intolerance to cold, weakness, or hair loss, see your doctor to make sure you don’t have a health problem.