Collagen Types · Epidermal stem cells and hemidesmosomes
Type XVII collagen: holding stem cells in place.
Type XVII is unusual. It is a transmembrane collagen in the outer skin’s anchoring structures, and reviews tie its decline to aging. Human evidence on restoring it is, in the reviewers’ words, scarce.
In short
- A 2025 review says type XVII collagen regulates the homeostasis of epidermal stem cells.1
- A 2026 review reports that collagen XVIIα1 levels decline with aging, and that these changes weaken junction integrity and are associated with photoaging and impaired repair.2
- The same review lists a shortage of rigorous human studies as a key gap.2
01
What it is
Collagen XVIIα1, encoded by COL17A1 and historically known as BP180 or BPAG2, is a type II transmembrane collagen enriched in hemidesmosomes of basal keratinocytes. Through interactions with integrin α6β4 and laminin-332 it links the keratin cytoskeleton to the basement membrane.2
It is also the major autoantigen in the blistering skin disease bullous pemphigoid, and recent work describes functions in cell proliferation, differentiation and aging.3
02
Aging and stem cells
The 2026 review says the anchorage supports epidermal homeostasis by preserving stem cell adhesion, polarity and regenerative capacity. During aging, collagen XVIIα1 levels decline and proteolytic processing increases, including ectodomain shedding.2
A 2022 review says stem cell self-renewal significantly decreases during skin aging but increases during wound repair, and focuses on collagen XVII as a niche component in both.4
In hair follicles, collagen XVIIα1 is required for follicle stem cell maintenance, and its reduction is linked to stem cell exhaustion and hair aging phenotypes.2
03
Can it be restored?
The 2026 review summarizes translational approaches that target collagen XVIIα1 and proposes in vivo readouts. It names key gaps: mechanism attribution, durable functional restoration at the junction, persistence in the skin and hair niche, and a shortage of rigorous human studies.2
What we could not confirm
The gaps, stated plainly.
- Whether any skincare product raises collagen XVII in human skin and keeps it raised. The reviewers list durable restoration and human studies as open gaps.
- How much of visible aging is caused by collagen XVII loss. The reviews describe association and mechanisms.
Questions
Common questions.
What is collagen XVII (COL17A1)?
A transmembrane collagen in hemidesmosomes of basal keratinocytes that links the keratin cytoskeleton to the basement membrane, according to a 2026 review.2
Does collagen XVII decline with age?
A 2026 review reports that levels decline and proteolytic processing increases during aging, which weakens junction integrity and is associated with photoaging and impaired repair.2
Keep reading
Back to the full guide: Collagen Types.
More in this guide
- Type I collagen: mechanical support of the dermis.
- Type III collagen: elasticity and barrier repair.
- Type IV collagen: the basement membrane’s scaffold.
- Type VII collagen: anchoring the epidermis to the dermis.
Related research
Sources
Where every claim comes from.
Numbers in brackets link to these entries. Journal entries were read as their PubMed record, and study details come from PubMed, the US National Library of Medicine. See every source on the Research Desk, organised by page.
- [1] Chinese Journal of Biotechnology (Li and colleagues), via PubMed. Roles of different types of collagen in skin aging and their research progress.
- [2] Journal of Dermatological Science (He and Zhuo), via PubMed. Collagen XVIIα1 in skin and hair aging: mechanisms, stem cell niche regulation, and translational strategies.
- [3] International Journal of Molecular Sciences (Tuusa and colleagues), via PubMed. BP180/Collagen XVII: a molecular view.
- [4] Theranostics (Liu and colleagues), via PubMed. Targeting the stem cell niche: role of collagen XVII in skin aging and wound repair.
This page is general information drawn from published reviews and studies. It is not medical advice and makes no claim about any Vanu Health product. The image is an AI-generated illustration, not a study image. Last updated October 30, 2026.