Sleeping with wet hair poses a higher risk of bacterial or fungal infections of the scalp. Fungi, such as Malassezia, can cause dandruff or even dermatitis. Additionally, moisture from the hair transfers to the pillow, creating ideal conditions (moist and warm environment) for fungal growth.

Sleeping with wet hair not only affects the scalp but also the hair itself. The scalp is weakest when the hair is wet, so it's not surprising that wet hair and hair ends are more prone to breakage during movements on the pillow compared to when they are dry.

When hair is still wet, avoid tight hairstyles (such as braids or tight buns), as wet hair is more elastic than dry hair and can inadvertently cause hair damage. If you use hair styling tools that create curls overnight, make sure to dry your hair before use to prevent damage and breakage.

If you prefer not to blow-dry your hair, wash it at least 2 hours before bedtime to allow it to air dry before sleeping. This will prevent damage and maintain the health of both hair and scalp.