Hyaluronic Acid

Hyaluronic acid (HA) is a naturally occurring molecule in the skin that can hold up to 1000 times its weight in water. This exceptional water-binding capacity makes it the gold standard hydrator in skincare. HA exists naturally in the dermis where it cushions and lubricates, but production declines with age, leading to dryness and loss of volume.

Japanese brands pioneered the use of multi-molecular-weight hyaluronic acid in a single product. Different molecular weights target different skin layers: high molecular weight HA (large molecules) hydrates the surface and forms a moisture-retaining film, medium molecular weight penetrates the epidermis, and low molecular weight (nano HA) reaches deeper layers for plumping from within.

Hada Labo, one of the most popular drugstore brands in Japan, built its entire line around this multi-weight HA philosophy. The brand helped popularize the layering hydration approach that is now a hallmark of Japanese skincare. You will find HA in nearly every Japanese moisturizer, serum, and toner, often labeled as sodium hyaluronate.