In addition to the brand's proprietary Protida complex that contains skin-soothing probiotics, the new Aurelia London Resurfacing Serum (£64) also contains bakuchiol (the plant-based ingredient that has similar effects on the skin as retinol, i.e. stimulate collagen production and smooth the surface of the skin) and 5% niacinamide, which in this formula helps reduce spots, regulate sebum production, and even out skin tone over time. The combination of the bakuchiol and niacinamide with the probiotics ensures the former two ingredients do their thing without causing your skin barrier to totally freak out.