You probably thought we tell you to just use retinol products at night because they are inactivated by sun (true), but there are specific differences in your skin in the daylight vs the night time hours.
Your skin has a biological clock.
The biological clock of your skin determines when the cells replicate, when the cells repair DNA aging damage, and how effectively toxins can be neutralized.
Your skin barrier permeability is higher at night, so you should use the thicker products that have less water and more oil to occlude the skin more at night
Sebum production is higher during the day, so if you are using products that control your sebum, put them on in the morning.
During the day the sebum production also causes your skin to have it’s highest pH. So products during the day that are most effective take this into account and absorb best at high skin pH levels.
At night, the skin is repairing, the blood flow is the highest, and medical grade products take this into effect.
So next time you ask for a moisturizer, be sure to ask what time of day it is formulated for!