In short
- Facial ligaments anchor the skin and soft tissue to bone. The long-held view was that ligaments stretch and loosen with age, causing sagging.1
- A 2023 animal study compared the zygomatic (cheekbone) ligament in young, middle-aged and older rats. The ligaments did not become more lax with age.2
- Instead, they became stiffer, with thicker collagen bundles, better-aligned fibres and fewer blood vessels.23
- This fits the view that the ligaments hold, while the fat, skin and soft tissue around them descend, alongside gradual bone loss.34
- It is an animal study and still needs confirming in people.
What facial ligaments are
Facial retaining ligaments are bands of fibrous tissue that run from bone up through the facial layers to the underside of the skin. They work like pins that hold skin and soft tissue in place.1 Key ligaments include:
- The zygomatic ligament, which holds the tissue over the cheekbone
- The mandibular ligament, at the front of the lower jaw near the end of the marionette line
- Ligaments around the eyes and in the temple
They are not equally strong. A 2025 cadaver study measured the force needed to push a cannula through each ligament. The zygomatic ligament took about 9.2 newtons, compared with about 3.6 newtons for the mandibular ligament, roughly 2.5 times as much.5
The old belief: stretched ligaments, sagging face
Drooping cheeks, deeper folds and more visible jowls with age were long explained by ligaments stretching and loosening until they could no longer support the tissue.1 That belief shaped treatment too, with an aim of "pulling ligaments back" or "tightening ligaments".
Clues that raised doubts
Facial anatomist Professor Sebastian Cotofana pointed to clinical observations that do not fit the old view:3
- Jowls usually stop at the mandibular ligament rather than spreading to the chin. If the ligament were slack, tissue would slide past it.
- The lower end of the marionette line stays indented, even in older or heavier patients, showing the anchor point is still holding the skin.
This led to a new hypothesis: the ligaments stay stable, and it is the tissue around them that loosens and moves down.
How the study was done
The Department of Plastic and Reconstructive Surgery at Guangdong Second Provincial General Hospital, China, working with Cotofana, published the study in Aesthetic Surgery Journal in 2023.23
- It examined the zygomatic ligament complex in rats of three ages: young, middle-aged and older
- Methods were histology, collagen immunohistochemistry and electron microscopy
- The authors describe it as the first study to use an ageing rat model specifically for facial ligaments3
What it found: not looser, but stiffer
| Measure | With age | What it means |
|---|---|---|
| Ligament laxity | Did not increase2 | The ligament did not stretch, as was long assumed |
| Stiffness | Increased, with thicker collagen bundles3 | The ligament holds more firmly and gives less |
| Fibre alignment | More aligned, less disorganised3 | Similar to tissue under constant tension |
| Blood vessels | Fewer, with signs of small-vessel decline3 | Consistent with age-related changes elsewhere in the body |
This helps explain the clinical clues. If ligaments stiffen with age, the mandibular ligament holds the jowl back from the chin even more, and the indent at the end of the marionette line stays visible as people get older.3
So why does a face sag?
If the pins hold firm, what changes is the fabric stretched between them. A review of the ageing face describes changes happening in several layers at once:4
- Facial fat: some deep compartments lose volume, while superficial fat moves down and folds over anchor points
- Skin becomes thinner and less elastic
- Facial bone gradually recedes, changing the base the ligaments attach to
Together, tissue between the ligaments descends and folds over the anchor points, creating the folds and jowls we see, with the ligaments marking their borders. Read more about the facial layers in the 5-layer facial anatomy article.
Limitations to keep in mind
- It is a rat study. Facial structure, tissue weight and the effect of gravity differ from humans, so results cannot be applied directly to people.
- It focused mainly on the zygomatic ligament. Other ligaments may change differently.
- Linking the findings to human jowls and marionette lines is the author's interpretation. It fits what is seen in clinic but has not been measured directly in people.3
What it means for treatment planning
If ligaments do not loosen, the goal shifts from "tightening ligaments" to caring for the tissue around them.
- Use ligaments as landmarks. Many folds sit along ligament lines. Filling only the fold without looking at the surrounding tissue can make the face heavier without addressing the cause.
- Restore deep support. As deep fat and bone recede, rebuilding support in the right places helps carry the tissue above, rather than adding a lot of superficial volume.
- Treat skin quality and the layers that have descended, for example with lifting or collagen stimulators, in the layer that has actually changed.
- Take care around very firm ligaments. Ligaments that stiffen with age affect how a cannula passes and how gel spreads, so knowing where they are is also a safety matter.5
This is the same principle as The Filler Architect approach: read the face layer by layer, from bone to skin, and decide which layers have truly changed before choosing a treatment. For a simpler summary, read Do "ligament lift" injections really work?
References
- Alghoul M, Codner MA. Retaining ligaments of the face: review of anatomy and clinical applications. Aesthetic Surgery Journal. 2013;33(6):769–782. PubMed 23855010
- Zhang et al. Age-Related Changes of the Zygomatic Ligament: An Experimental Animal Study. Aesthetic Surgery Journal. 2023. doi:10.1093/asj/sjad235 (with Commentary: doi:10.1093/asj/sjad291)
- Cotofana S. Do Facial Ligaments Age? Cotofana Anatomy Blog. cotofanaanatomy.com
- Cotofana S, Fratila AAM, Schenck TL, Redka-Swoboda W, Zilinsky I, Pavicic T. The Anatomy of the Aging Face: A Review. Facial Plastic Surgery. 2016;32(3):253–260. doi:10.1055/s-0036-1582234
- Hong GW, Kim SB, Chua D, et al. Quantifying the Strength of the Facial Ligaments and Its Clinical Implications. Aesthetic Plastic Surgery. 2025;49(22):6227–6233. doi:10.1007/s00266-025-05060-y
This article is for general information and is not personal medical advice. Results vary from person to person. Please see a doctor for a facial assessment before choosing a treatment.