Nasolabial folds are caused by a combination of underlying facial anatomy, age-related volume loss, bone resorption, repetitive muscle movement, and external factors like sun exposure and smoking. Everyone has some degree of nasolabial folding because the lines mark a natural boundary between the cheek and upper lip. But several processes, some within your control and some not, determine how deep and prominent those folds become over time.
The Anatomy Behind the Fold
The nasolabial fold isn’t a wrinkle in the traditional sense. It’s a structural crease formed where several facial muscles insert directly into the skin. The muscles responsible for lifting your upper lip, including those that pull upward when you smile, attach to the skin right along the fold line. Every time these muscles contract, they tug on the skin in a way that reinforces the crease.
Two ligaments on either side of the fold anchor the deeper tissues to the skin’s surface. The one on the outer side of the fold connects the underlying connective tissue to the skin, while the one on the inner side is a sturdier structure that attaches directly to bone. Together, these ligaments act like tethering points. The skin on either side of them can sag or shift, but the fold line itself stays put, which is exactly why the crease becomes more visible as surrounding tissue changes with age.
How Facial Fat Loss Deepens the Crease
Your face contains distinct pockets of fat arranged in layers, and these compartments don’t all age at the same rate. The deeper fat pads in your midface deflate first. When they shrink, they stop supporting the more superficial fat that sits on top of them. That surface-level fat then slides downward under gravity, a process sometimes called pseudoptosis, piling up along the nasolabial fold and making it look deeper and more prominent.
This isn’t just a surface problem. As the deep fat in the inner cheek area deflates, it creates a chain reaction: the overlying cheek fat descends, the transition between your lower eyelid and cheek becomes harsher, and the nasolabial fold sharpens. The fold deepens not only because tissue is accumulating above it but also because the structural support beneath it is disappearing.
Bone Loss in the Midface
For decades, sagging skin and shifting fat got all the blame for deeper nasolabial folds. But the facial skeleton itself changes significantly with age, and the upper jaw (maxilla) is one of the most vulnerable areas. The maxilla loses projection over time, retreating backward. Measurements from CT imaging show the maxillary angle decreases by about 10 degrees between people under 30 and those over 60, representing a meaningful loss of the bony scaffolding that holds the midface forward.
The opening of the nasal cavity also enlarges as its bony edges recede, with the greatest bone loss occurring at the lower rim. This weakens support for the base of the nose and the upper lip, pulling the nasolabial crease further back and making the fold more pronounced. What looks like sagging soft tissue is partly the face losing the skeleton it was draped over. The development of a prominent nasolabial fold and groove can, to a significant degree, be traced to this loss of maxillary projection.
Repetitive Facial Expressions
Every smile, laugh, or grimace activates the muscles that pull along the nasolabial fold. Over years, this repetitive contraction has a cumulative effect. Research on similar facial muscles, specifically those between the eyebrows, has shown that repeated activation creates a low-level residual tension that persists even during relaxation. The muscle doesn’t fully “turn off,” and over time this baseline tension increases, producing visible creases even when the face is at rest.
The same principle applies to the nasolabial area. People who are especially expressive or who frequently engage their smile muscles may develop more prominent folds earlier. Everyday activities like animated conversation, concentrating, or reacting emotionally all contribute small amounts of cumulative muscle activation that gradually etch the fold deeper into the skin.
Weight Fluctuations and Facial Volume
Significant weight loss is one of the fastest ways to deepen nasolabial folds. A systematic review of facial changes after bariatric surgery found that midface volume loss was the most common change, appearing in 88% of cases. Fat loss from the cheeks and lips accelerates nasolabial folding, and the resulting pseudoptosis, where deflated tissue droops downward, directly deepens the crease.
You don’t need to lose a massive amount of weight for this to matter. Even moderate weight fluctuations over the years reduce the fat volume in your cheeks. The midface is particularly sensitive because the fat compartments there are relatively thin and sit over bone. Once that volume is gone, the skin has less to drape over, and the fold becomes more noticeable. Repeated cycles of gaining and losing weight can compound this effect by stretching the skin and then leaving it without adequate support.
Sun Damage and Smoking
Ultraviolet radiation breaks down collagen and elastin, the two proteins responsible for keeping skin firm and elastic. The cheeks receive substantial cumulative sun exposure over a lifetime, making the nasolabial area especially vulnerable to photoaging. As the structural proteins in the skin degrade, the tissue becomes less resilient and folds more easily under gravity and muscle tension.
Smoking compounds this damage through a different mechanism. Smokers have fewer collagen and elastin fibers in the deeper layers of their skin, and smoking actively suppresses the body’s ability to repair and rebuild these proteins. The result is skin that becomes slack, hardened, and less elastic. When smoking and sun exposure overlap on the cheeks, the combined effect is particularly significant, accelerating the structural breakdown that deepens nasolabial folds well beyond what normal aging alone would produce.
Why Some People Have Deeper Folds Than Others
Clinicians grade nasolabial fold severity on a six-point scale, from no visible wrinkle to a very deep, redundant fold. Where you fall on that spectrum depends on how many of the above factors apply to you, and how strongly. Genetics determine your baseline facial structure: the size and position of your fat compartments, the density of your bone, and how quickly your collagen breaks down. Ethnicity and skin type influence how your skin responds to sun exposure and gravity.
Lifestyle factors layer on top of that genetic foundation. Someone with naturally robust midface volume, minimal sun exposure, and a stable weight may not develop noticeable folds until their 50s or 60s. Someone with thinner facial fat, a history of smoking, and significant weight fluctuations might see pronounced folds in their 30s. The fold itself is a normal anatomical landmark. Its depth is the variable, and that depth reflects the interaction between your unique facial structure and everything it’s been exposed to over time.