What is the primary cause of excessive oiliness on the scalp?

The primary cause of excessive oiliness on the scalp is overactive sebaceous glands. These glands are responsible for producing sebum, which is an oily substance that helps to keep the scalp and hair moisturized. When these glands become overactive, they produce an excessive amount of sebum, leading to an oily scalp. This can result in various conditions such as greasy hair, dandruff, or even acne on the scalp.

While factors like poor diet, heavy hair products, and infrequent hair washing can contribute to scalp conditions, they do not primarily cause excessive oiliness. Poor diet may affect skin and scalp health overall, but it is not the direct cause of increased oil production. The use of heavy hair products may lead to buildup, which can make hair look greasy but doesn't change the underlying production of sebum. Similarly, infrequent hair washing can lead to an accumulation of oil and dirt, but the core issue of excessive oiliness stems from the sebaceous glands' activity. Thus, an overabundance of oil on the scalp directly relates to these glands working more than normal.