YSL Rose Loulou (124) is a warm coral with a luminous finish that is permanent and retails for $38.00. In comparison, YSL Nude Avant-Garde (91) is a warm pink with a luminous finish that is limited edition and retails for $38.00.
YSL Nude Avant-Garde (91) is 90% similar — it is more shimmery, darker, glossier.
