Medical Encyclopaedia › Collagen (short definition)
In brief: Collagen is the most abundant protein in the human body. As a structural protein, it gives skin, tendons, cartilage, bones and blood vessels strength and tensile stability.
Structure and types
Collagen consists of three intertwined protein chains that are particularly rich in the amino acids glycine, proline and hydroxyproline. To form it, the body needs vitamin C, among other things. There are numerous types of collagen: type I dominates in skin, bone and tendons, type II in articular cartilage, type III in vessels and elastic tissue.
Collagen and ageing
From about the age of 25, collagen formation gradually decreases while breakdown increases. UV radiation, smoking and high blood sugar levels accelerate this process. The result is thinner, less elastic skin and wrinkles. Hereditary disorders of collagen formation lead to diseases such as Ehlers-Danlos syndrome or osteogenesis imperfecta.
Collagen supplements – what do studies show?
Collagen hydrolysates are offered as food supplements. Some studies report slight improvements in skin elasticity and moisture or less joint discomfort in athletes. However, many of these studies are small, short or funded by manufacturers; their overall validity is limited. Ingested collagen is broken down into fragments in the gut and is not incorporated into the skin unchanged. There are no authorised health claims for collagen in the EU.
Collagen in aesthetics
Aesthetic medicine attempts to stimulate the body’s own collagen formation – for example with retinoids, microneedling, laser or so-called biostimulators. The effects are usually moderate and side effects are possible; individual counselling is important.
Related terms in the encyclopaedia
Connective tissue, Fibroblasts, Elastin, Skin ageing, Vitamin C, Ehlers-Danlos syndrome, Biostimulators, Microneedling, Food supplements
Further reading on Medizin Aktuell
Sources
- Verordnung (EG) Nr. 1924/2006 über nährwert- und gesundheitsbezogene Angaben über Lebensmittel und EU-Register der zugelassenen Angaben
- Verbraucherzentrale: klartext-nahrungsergaenzung.de – Kollagen
Note: This article is for general information and does not replace advice, diagnosis or treatment from a doctor or pharmacist. Last updated: October 2026.