Refers to sodium hyaluronate with a molecular weight of less than 1000 Da (tiny in size, powerful in effect). With an average molecular weight of around 1000 Da, this form primarily consists of disaccharides, tetrasaccharides, and hexasaccharides. Each sugar unit in a hyaluronic acid molecule has a molecular weight of approximately 397, measuring about 1 nm in size. Therefore, the particle size of 1000 Da hyaluronic acid is roughly 6 nm.