The secretion of sebaceous glands which causes acne in adolescents is known as:
sebum
The sebaceous glands are microscopic exocrine glands in the skin that secrete an oily or waxy matter called sebum to lubricate and waterproof the skin and hair of mammals. Acne is a very common problem, particularly during puberty in teenagers and is thought to relate to an increased production of sebum due to hormonal factors.