Insufficient secretion of skin sebum leads to dullness, tightness, peeling and dryness.
Normal skin has elastic and firm skin, even skin tone, and the skin is neither oily nor dry.
The sebaceous glands are overactive and the whole face is obviously oily, often with blackheads, acnes, and enlarged pores.
The level of water and sebum is imbalanced on different part of the face, mainly oily on the T-zones (forehead, nose and chin), and dry on the cheeks.
Mainly due to excessive sebum secretion, hormonal imbalance and stress, which can cause acnes, blackheads and enlarged pores, and even form papules, pustules, nodules and cysts.
Sensitive skin allergens are mainly genetic or caused by skin care products' preservatives or fragrances, which leads to dryness, tightness and eczema. The most common are rosacea, seborrheic dermatitis and atopic dermatitis.