Biologique Recherche Quintessential Serums are highly concentrated, targeted treatments designed to address specific skin concerns with pure, active ingredients. These serums penetrate deeply to replenish, repair, and restore the skin at a cellular level. Whether you need hydration, brightening, firming, or soothing, each serum is formulated to deliver precise, powerful results without unnecessary fillers. Mix, layer, or use alone, these serums are the ultimate custom addition to any skincare routine for a healthier, more radiant complexion.