Why does my face feel greasier during the day?

Sebum production is lowest at night and increases throughout the day. Since the highest concentration of sebaceous glands is on the face, especially in the “T zone,” this increased production of sebum during the day can make your face feel greasier. Sebaceous gland activity also increases in response to hormones, stressors, and irritants. The face can also feel greasier throughout the day depending on products used on the face and in the hair. The heavier the product, the more likely it is to be occlusive and cause buildup of sebum on the skin. There are also sweat glands on the skin, and in times of increased heat or stress, these glands increase production of sweat which, when combined with sebum, makes the skin look shinier and feel oilier. For women, increased sebum production begins approximately 1 week before the menstrual period, which also makes the face feel oilier.