Greasy hair can be frustrating, especially when it occurs the morning after washing. If you are experiencing this issue, you may be wondering why your hair seems excessively oily after sleeping.

Waking up with greasy hair can have various causes. One reason is that the scalp produces sebum (1) at night, leading to oily hair in the morning. Read on to learn more about why your body might be producing excess sebum, as well as some tips on how to tackle the issue so you wake up looking fresh.