An oily hair and scalp treatment should be used when there is __________.

An oily hair and scalp treatment is specifically designed to address the issue of excessive oiliness that results from overactive sebaceous glands. When these glands produce oil in excess, it can lead to a greasy appearance and potentially disrupt the health of the hair and scalp, causing issues such as dandruff or scalp irritation.

The purpose of an oily hair and scalp treatment is to balance the oil production, remove excess oil, and cleanse the scalp. This treatment often contains ingredients that help control oil production and offer a fresh feeling to the hair and scalp.

In contrast, dry hair and scalp conditions require different treatments that focus on adding moisture rather than removing oil. Therefore, options highlighting dryness, lack of moisture, or normal oil production are not appropriate for this specific treatment approach.