I use my Mia just once per week, as a deeper cleaning/exfoliating treatment. I use the white brush (sensitive?) and get shiny skin as well. I also assumed it was due to the effective cleansing and removal of dead skin cells on the surface. The shine is gone a few hours later, and I haven't had it show through my makeup.
Location: Texas
Type: 3b/3c (i), below shoulder length.
CO wash: A-O GPB LYY, Desert Essence Coconut, Oribe Silverati
Leave-ins: Curl Junkie Beauti-Curls, KCKT, cno overnight
Styling: BRHG, MGA Sculpting Gel, A-O Mandarin Magic Gel, LOTD AVG, LALSG, CJ Pattern Pusha
DT: Curl Junkie Deep Fix, Briogeo Don't Despair Repair!