The over-cleansing rebound cycle
Removing surface sebum below a threshold triggers keratinocyte signalling that upregulates 5-alpha reductase and androgen-sensitive lipid synthesis in sebocytes. Sebometry studies show that skin stripped to <0.5 mg/cm² sebum will "rebound" to elevated sebum levels 2–3× baseline within 48 hours — a measurably worse starting point.