Why is my skin oily during the day and then feels tight and dry at night?

One of my patients this week asked me a very good question: ‘why is my skin oily during the day and then feels tight and dry at night?’

She was concerned about using an ointment at night, that it would make her skin more oily during the day. This highlights a key point about skin: hydration and oiliness are not the same things. This can get into quite a complicated discussion about how skin ‘works’ but for the sake of clarity and Instagram caption character limits I will focus on the ‘headlines:’ ‘Hydration’ refers to the amount of water in your epidermis.

The best way to increase hydration is by reducing transepidermal water loss and the best way to do that is by using an occlusive moisturiser (the best occlusive moisturiser is plain old Vaseline). ‘Oiliness’ is due to the amount of sebum (oil) secreted by your skin oil glands (sebaceous glands).

This is regulated primarily by hormones and genetics. Skin surface oil can also act as an occlusive so the two concepts are of course related. But using an ointment at night won’t increase oiliness during the day but it will increase hydration which will make your skin generally look and feel better.