Various tetracyclines and erythromycins have been used rather empirically for the systemic treatment of acne vulgaris for more than a decade. It has been impossible to accurately evaluate clinically the numerous derivatives and to compare their effectiveness with other antibiotics such as clindamycin. As a substitute for this approach, this present study ranks these antibiotics, when given orally, as to their effectiveness in suppressing the fatty acids in sebum in normal volunteers. As a group, the tetracyclines were more effective than the erythromycins in decreasing the fatty acids, but clindamycin was significantly more potent than either.
Pablo GM, Fulton JE. Sebum: Analysis by Infrared SpectroscopyII. The Suppression of Fatty Acids by Systemically Administered Antibiotics. Arch Dermatol. 1975;111(6):734-735. doi:10.1001/archderm.1975.01630180062006