Facial serum with hyaluronic acid and ectoine. It moisturises your skin on several levels. Its light texture also makes it suitable for oily skin. And as hyaluronic acid is an endogenous and well-tolerated substance, sensitive skin also benefits.hyaluronic serum is a 360° skincare product. This is because long and short-chain hyaluronic acid molecules accumulate at different depths in the skin and develop their effect there in the short and long term: Apply a few drops to cleansed skin in the morning and evening and massage in gently.