What Causes Wrinkles: Collagen, Sun, and Time

Wrinkles form when the scaffolding under your skin breaks down faster than it rebuilds, and the surface starts folding along the lines your face already uses. What causes wrinkles is therefore two forces working at once: time, which slows the rebuild, and ultraviolet light, which speeds up the breakdown.

Of those two, only one is negotiable. You cannot pause the first. You have quite a lot of say over the second, and sun exposure is the largest single modifiable driver of visible skin aging. That is settled ground in dermatology, and it is the most useful sentence in this article.

Here is what is actually happening under the surface, in order.

What causes wrinkles at the structural level

Collagen is the scaffolding

The dermis, the thick layer beneath the surface, is mostly collagen. Collagen fibers give skin its tensile strength and hold it taut against the shape underneath. Fibroblasts, the cells living in the dermis, build and maintain that network continuously.

Two things happen with age. Fibroblasts produce less new collagen, and the existing collagen sits around longer, accumulating damage. The network gets sparser and more disorganized. Skin loses the internal tension that kept the surface smooth, so the surface starts recording every fold it makes.

Elastin is the recoil

Elastin fibers are the reason skin snaps back after you pinch it. There is far less elastin than collagen, and the body is poor at replacing it in adult skin. Once elastin is degraded it largely stays degraded.

Sun-damaged skin does something specific here. Abnormal elastic material accumulates in the upper dermis instead of proper fiber, a change dermatologists call solar elastosis. It is why heavily sun-exposed skin develops a thickened, leathery, deeply creased quality that is different from the fine crepiness of skin that has been kept covered.

The water in between

Between the fibers sits a gel of glycosaminoglycans, hyaluronic acid among them, which holds water and gives the dermis its volume. That water content falls with age. Less volume under the surface means the surface has more slack, and slack skin folds.

Dynamic lines and static lines are not the same problem

This distinction decides what will and will not help you, so it is worth getting straight.

	Dynamic lines	Static lines
What they are	Folds that appear when the muscle moves and vanish when it relaxes	Folds visible on a still, relaxed face
Where they show first	Forehead, between the brows, outer corners of the eyes	Anywhere a dynamic line has been repeating for years, plus the cheeks and neck
Cause	Repeated muscle contraction against skin	Structural loss in the dermis, so the fold no longer springs out
Direction of travel	Becomes a static line over time as the dermis thins	Does not go back to being dynamic
What acts on it	Reducing the movement. This is a doctor's territory, not a serum's.	Anything that supports the dermis: sun protection first, retinoids, in-office resurfacing

The practical takeaway: a topical product acts on the second column, slowly. Nothing you apply relaxes a muscle. Any product implying otherwise is describing an outcome it cannot deliver.

Sun is the driver you can actually control

Ultraviolet light does two things to the dermis simultaneously. It damages existing collagen directly, and it prompts skin cells to produce enzymes called matrix metalloproteinases, which break collagen down. So UV raises the demolition rate at the same time age lowers the construction rate. That combination is the engine of visible facial aging.

The classic demonstration of this is not a study you need to look up, it is your own body. Compare the skin on your inner upper arm, which has spent your entire life covered, to the skin on the back of your hand. Same age, same genes, same person. The difference between them is accumulated light.

UVA penetrates deeper than UVB, passes through window glass, and is present all day and all year. It is the wavelength range most associated with the dermal changes described above. That is why daily broad-spectrum sunscreen is boring advice that happens to be the highest-value thing on any anti-wrinkle list, and why it beats every serum in the drawer.

The other accelerators

• Smoking. It restricts blood supply to the skin and is associated with degraded collagen and elastin. The pattern is recognizable enough that dermatologists can often spot it.
• Glycation. Sugars in the bloodstream bond to collagen fibers and cross-link them. Cross-linked collagen is stiffer and less able to spring back. This is ordinary biochemistry, not a diet fad, and it is one reason blood sugar control shows up in skin conversations.
• Sleep position. Pressing the same side of your face into a pillow for decades creates sleep lines, usually vertical on the cheek. They start as creases that fade by noon. They stop fading.
• Repeated expression. Squinting counts. If you are outdoors without sunglasses, you are running the muscle and taking the UV at the same time.
• Dryness. Dehydrated skin does not cause wrinkles, but it exaggerates every line you already have. This is why a good moisturizer appears to work overnight and then appears to stop working. It never worked on the dermis at all.
• Hormonal change. Estrogen influences collagen content and skin thickness, and the menopause transition brings a measurable shift in both. This is a conversation for a physician, not a shopping decision.

What happens at the surface, too

Wrinkles get written in the dermis, but they get read at the surface. Epidermal turnover slows with age, so dead cells linger and the surface gets rougher. The junction between the epidermis and dermis, which is corrugated in young skin, flattens out, which reduces the mechanical grip between the two layers.

Underneath all of it, the facial fat pads shift downward and lose volume, and the bone underneath remodels. Some of what reads as wrinkling is really the skin above having more area than the structure below needs. No cream addresses that. Being told otherwise is how people end up disappointed by products that were never in a position to help. The wider version of that structural picture, and which parts of it you can influence, is in what causes skin aging, and what you control.

What actually slows it, ranked honestly

1. Broad-spectrum sunscreen, daily, all year. Nothing else on this list is close. It works on the demolition side of the equation, which is the side you can influence.
2. Not smoking. Second on the list and not a close third.
3. A retinoid. The most studied topical category for lines and texture. It works on epidermal turnover and on the dermis over months. Prescription strengths are stronger and so are their side effects.
4. Consistency over intensity. Three years of a simple routine outperforms three weeks of an elaborate one, every time.
5. In-office procedures. Lasers, energy devices, professional microneedling and injectables act more directly on the dermis or the muscle. A dermatologist is the right person to scope these.
6. Sleep, blood sugar, alcohol. Real, slower, and harder to see in isolation. Worth doing for other reasons anyway.

Note what is not on that list: any single ingredient sold as the answer. If you want the plain-language version of what each active category is aimed at, skincare actives explained covers it without the marketing.

Why a good formula still may not reach the dermis

There is an obstacle sitting between every anti-wrinkle product and the layer it is written about. Collagen lives in the dermis. The outer layer of your skin is a barrier, and its job is to keep things out. It does not care what your serum cost. Most of what you pat on stays on top, dries, and ends up on your pillow.

That is the whole reason people conclude their skin is broken after a year of doing everything right. It was never your skin. It never got in. We set out the barrier argument in full on our page on how the barrier works and what crosses it, and in shorter form in why your serum is not absorbing.

Microneedling opens temporary channels through that outer layer, which gives a formula a route rather than a surface. Depth is the whole variable: shallow settings sit near the surface, deeper settings reach toward the dermis where collagen actually lives. The microneedling depth guide explains how that dial maps to layers, and what microneedling is is the right starting point if this is new.

Our deep-setting ampoule, the 03 wrinkle ampoule, carries Acetyl Hexapeptide-8 at 500 ppm, which is 0.05 percent, plus adenosine at 0.04 percent. Those are concentrations. They are not predictions. We will describe what is in the vial and what the device does at the moment the needle meets skin, and we will leave the outcome claims to brands willing to make them. If you want help matching a concern to a position on the dial, the ampoule finder does that in about a minute.

Frequently asked questions

At what age do wrinkles start?

Collagen production begins declining in most people during their twenties, long before anything is visible. The first lines usually appear as dynamic lines in the areas with the most repeated movement, the forehead and the outer eye corners, in the late twenties or thirties. Sun exposure moves that timeline forward. Genetics and skin tone move it in both directions.

Can wrinkles be reversed?

Dynamic lines respond to reducing the movement, which is a medical procedure. Static lines are structural, and topical products act on them slowly and partially at best. In-office resurfacing goes further. Anyone promising to erase a static line with a cream is describing something the category cannot do. The honest framing is slowing the rate, not reversing the state.

Does drinking water prevent wrinkles?

No. Dehydrated skin makes existing lines more visible, so hydration improves how your face looks today. It does not change collagen density in the dermis, which is where wrinkles are actually determined. Drink water because your body needs it, not as a wrinkle strategy.

Is sunscreen really more important than a retinoid?

For prevention, yes. Sunscreen reduces the ongoing damage, and a retinoid works on skin that is still being damaged every day if you skip it. The sequencing is simple: sunscreen is the foundation, and everything else is built on top of it. Doing both is better than choosing.

Do sleep lines really become permanent?

Repeated compression against a pillow creates creases that fade less and less as dermal support thins. Many people notice them first in their thirties as a vertical line on one cheek that lasts until midmorning. Sleeping on your back avoids the mechanism. Whether you can retrain your sleep position is a separate question.

What about the pores and dark spots that show up at the same time?

They share a cause. The same loss of dermal support that lets a fold set also lets a pore rim slacken, which is covered in what causes large pores. The same UV exposure that drives collagen breakdown also drives pigment production, covered in why pigment clusters into dark spots. Sun protection is the one intervention that appears in all three articles, which should tell you something.