Final answer:
For combination skin, emollients, exfoliants, and humectants can be beneficial, while oil-balancing ingredients may not be necessary and could over-dry certain areas.
Step-by-step explanation:
To treat combination skin, one must carefully select ingredients that address both dry and oily areas without exacerbating either condition. Ingredients that are commonly found in moisturizing creams include water, oil, emulsifiers, and thickening agents. Emollients, such as oils, help to smooth and soften the skin by filling in the gaps between skin flakes, which is great for dry areas of combination skin.
Exfoliants help in the removal of dead skin cells, which can be beneficial for the oily and acne-prone areas. Humectants draw moisture into the skin from the environment or deeper layers of skin, which can be beneficial in dry environments or for the dry areas of the skin. However, an oil-balancing ingredient would generally not be necessary in a moisturizer for combination skin, as it is specifically aimed at controlling excess oil, which could potentially over-dry the already dry areas of combination skin.