I found information on several products that contain hyaluronic acid, including HDM Serum Facial Ácido Hialurónico, Idraet Serum Hialuronico, and Hyaluronic Acid Serum. The ingredients for these products are listed below:

• HDM Serum Facial Ácido Hialurónico: Deionized Water, Propylene Glycol, Glycerin, Urea, Sodium Hyaluronate.
• Idraet Serum Hialuronico: Water, Propylene Glycol, Calcium Carboxymethyl Cellulose, Diazolidinyl Urea.
• Hyaluronic Acid Serum: The ingredients for this product are not listed in the search results, but it is described as a vegan, paraben and sulfate-free serum with gentle and effective clean ingredients.

In addition, I found the ingredients for a hyaluronic acid serum sold on Amazon:

• Hyaluronic Acid Serum for Face & Skin: Demineralized Water, Vegetable Glycerin, Sodium Hyaluronate (Hyaluronic Acid), Citric Acid, Polysorbate 20, Potassium Sorbate, Sodium Benzoate.

Hyaluronic acid is a natural polysaccharide found in connective tissues such as cartilage. It is commonly used in skincare products as a hydrator, moisturizer, and to reduce the appearance of wrinkles.