Medical Encyclopaedia › Hyaluronic acid (short definition)
In brief: Hyaluronic acid is a sugar molecule produced by the body that can bind large amounts of water. It occurs in the skin, connective tissue, synovial fluid and the vitreous body of the eye, where it provides moisture, elasticity and lubrication.
Function in the body
In the skin, hyaluronic acid stores water and contributes to plumpness and firmness. In joints, it acts as a lubricant and shock absorber. With increasing age, its content in the skin decreases, which contributes to dryness and wrinkles.
In skincare and eye drops
In creams and serums, hyaluronic acid binds moisture on the skin surface and can make the skin appear temporarily smoother and plumper. Deeper wrinkles are not removed by this. In eye drops, it relieves the symptoms of dry eyes.
As a filler
Cross-linked hyaluronic acid is injected under the skin as a filler to build volume or fill wrinkles, for example on the lips, cheeks or nasolabial folds. Depending on the product and area, the effect lasts about six to 18 months. Fillers are medical devices; treatment should only be carried out by a doctor after detailed information.
Risks of fillers
Swelling, redness and bruising are common. Less often, nodules, inflammation or migration of the material occur. A rare but serious complication is the blockage of a blood vessel, which can lead to tissue damage and, in the face, in the worst case to blindness. Warning signs are severe pain, blanching or bluish discoloration of the skin and visual disturbances – immediate medical help is then necessary. Hyaluronic acid fillers can be dissolved with the enzyme hyaluronidase.
Joint injections and food supplements
In knee osteoarthritis, hyaluronic acid is sometimes injected into the joint; according to current evidence, the benefit is small. There are no authorised health claims in the EU for hyaluronic acid as a food supplement.
Related terms in the encyclopaedia
Filler, Hyaluronidase, Vascular occlusion after filler, Lip filler, Skin booster, Skin ageing, Dry eye, Knee osteoarthritis, Medical device
Sources
- Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM): Informationen zu Medizinprodukten
- Deutsche Gesellschaft für Orthopädie und Unfallchirurgie (DGOU): S2k-Leitlinie Gonarthrose
- Europäische Kommission: EU-Register für nährwert- und gesundheitsbezogene Angaben
Note: This article is for general information and does not replace advice, diagnosis or treatment from a doctor or pharmacist. Last updated: October 2026.