The reasons why our face feel greasier throughout the day is due to several factors as mentioned below:
Sebaceous glands - Highest concentration of sebaceous glands on our face, especially in the "T zone," that caused the increased in production of sebum during the day is one of the main reason why our face feel greasier during the day. Besides, sebaceous gland activity also increases in response to hormonal changes, stressors and irritants.
Product we used on our face and in our hair – It is good to know that the heavier the product we used, the more likely it is to be occlusive and cause buildup of sebum on our skin.
Sweat glands on our skin – In times of increased heat or stress, our sweat glands will increase production of sweat which, when combined with sebum will make our skin look shinier and feel oilier.
Menstrual period (i.e. the monthly, cyclical bleeding cycle women experience when they are not pregnant, irregularities in this cycle signal hormonal imbalance that can be an aggravating factor in acne) - For women, sebum production will tend to increase approximately 1 week before the menstrual period, this will make the women face feel oilier. It is suggested to carry some blotting pads that are specifically designed to absorb this oily mixture off our skin, though the relief is said to be temporarily.
What are the solutions then?
It is of great help if we could address the underlying issue by controlling our body temperature as much as possible, managing stressors well and try using products that will not substantially increase the sebum production whenever possible. These shall include products that contain salicylic acid (i.e. ingredient that helps exfoliate the upper layers of our skin, and is commonly found in over the counter acne treatment products) or retinols (i.e. Vitamin A).