How are dry, normal, oily, and combination skin types classified?
Skin types are classified based on the distribution of sebum in the T-zone and U-zone (the number of sebum units per unit area):
1. Dry: Both T-zone and U-zone are dry, or a mix of normal and dry.
2. Normal: Both T-zone and U-zone are neutral.
3. Oily: Both T-zone and U-zone are oily, or a mix of normal and oily.
4. Combination: A mix of oily and dry skin types.
1. Dry: Both T-zone and U-zone are dry, or a mix of normal and dry.
2. Normal: Both T-zone and U-zone are neutral.
3. Oily: Both T-zone and U-zone are oily, or a mix of normal and oily.
4. Combination: A mix of oily and dry skin types.