Androgens are the root trigger — testosterone and DHT bind to sebaceous glands and crank sebum production, which clogs follicles and feeds C. acnes bacteria. Four amplifiers stack on top: the luteal phase of the menstrual cycle (the week before your period), cortisol from chronic stress, dairy (especially skim milk, which raises IGF-1), and high-glycemic foods like white bread and sugary drinks. PCOS is the strongest underlying driver in women under 35 — jawline and chin cysts are the tell. Treatment that addresses the cause rather than the spot: spironolactone, combination oral contraceptives with drospirenone, or a 0.025% to 0.1% tretinoin nightly. A microneedle patch like ZitSticka manages individual cysts.