You’ve probably heard it a hundred times: sun exposure ages your skin and breaks down collagen.
But how, exactly?
Most people picture collagen loss like a fuel tank slowly emptying — a little less collagen with every summer.
The reality is more aggressive than that.
Sun exposure doesn’t just use up your collagen. It switches on enzymes that actively shred it — while also shutting down your skin’s ability to make more. Here’s what’s really happening under the surface.
1. It doesn’t wait for a sunburn — or even a tan
You don’t need to burn, or even tan, for the damage to start.
Here’s what happens when UV hits your skin:
- Within hours, your skin cells go into a stress response
- Part of that response is releasing enzymes called MMPs (matrix metalloproteinases)
- Normally, MMPs help recycle old collagen in small amounts
- Under UV stress, they go into overdrive — switched on by the hundreds, sometimes thousands, within 24 hours
- At the same time, your skin’s production of new collagen drops sharply, and can stay suppressed for several days
In short: one afternoon in the sun can cause a short-term collagen deficit. Breakdown goes up. Production goes down. Both at once.
2. The enzymes don’t dissolve collagen — they shred it
It’s tempting to picture collagen “melting away” in the sun.
What actually happens is more like scissors:
- MMP-1, the main collagen-cutting enzyme, makes one precise cut through a collagen fibre¹
- That single cut is enough — the fibre unravels
- Once unravelled, it’s easy prey for further breakdown by other enzymes
The result isn’t an even, gradual thinning. It’s fragmentation — frayed, disorganised, weaker collagen sitting right alongside healthy collagen in the same patch of skin.
3. Those fragments then sabotage new collagen production
This is the part that surprises most people — and it’s arguably the most important mechanism of all.
- Fibroblasts are the cells that produce your collagen
- They need to physically anchor to intact collagen fibres to keep producing more²
- Surrounded by broken fragments instead, they lose that anchor — and slow down
That creates a self-reinforcing cycle:
- Sun damage creates collagen fragments
- Fragments discourage fibroblasts from making replacement collagen
- Less new collagen means the skin relies more on old, damaged fibres
- Repeat
It’s a feedback loop, not a simple leak.
4. UVA plays a bigger role than most people realise
Sun-safety advice usually focuses on UVB, the ray behind sunburn. But for collagen specifically, UVA matters just as much — arguably more.
- UVA makes up most of the UV radiation that reaches the earth’s surface
- It penetrates deeper into skin than UVB, reaching the dermis, where collagen actually lives
- It passes through window glass and cloud cover far more easily than UVB
That means collagen-degrading pathways can be triggered by:
- Driving with the sun on one side of your face
- Sitting near a window at work or at home
- Overcast days, when UV feels lower than it actually is
- Everyday walking, gardening or exercise outdoors — not just beach days
If sun protection only happens on obviously sunny beach days, the exposure that matters most for collagen may be getting missed entirely.
This matters even more if you live in Melbourne.
Melbourne’s weather is famously changeable — cool mornings, grey skies, “four seasons in a day.” But UV doesn’t follow the temperature. SunSmart Victoria’s own guidance is that UV sits at 3 or above (the level requiring protection) from September right through to April, regardless of how mild or overcast it feels. A cool, cloudy Melbourne day in October can still be quietly triggering the same collagen breakdown as a hot, clear one.
5. Collagen isn’t the only casualty — elastin takes a hit too
Collagen gets most of the attention, but it isn’t alone.
UV exposure also activates a separate group of enzymes (including cathepsin K) that break down elastin — the protein responsible for skin’s ability to spring back into place.
This is why sun damage often shows up as a combination of things at once:
- Fine lines — from collagen fragmentation
- Looser, less resilient skin — from elastin damage
- Leathery texture and patchy pigmentation — from other UV pathways
6. The damage is measurable years before you can see it
Perhaps the most sobering finding: reduced collagen activity has been detected in the sun-exposed skin of young adults, well before any visible signs of ageing appear.
That means this process isn’t something that switches on later in life once wrinkles start. It’s active every time skin meets significant UV — quietly building up long before it shows in the mirror.
It’s also why two people the same age, with similar genetics, can look noticeably different. Compare skin that’s rarely seen the sun (like the underside of your upper arm) with your face, neck or hands. One reflects the passage of time. The other reflects years of this cycle repeating.
So — can sun-damaged collagen come back?
To an extent, yes. And this is exactly where laser treatment comes in — because it works directly on this cycle, not just around it.
Why laser treatment targets this specific problem
Remember the trap: fragmented collagen discourages fibroblasts from making new collagen, which leaves more fragments in place, which suppresses production even further. Left alone, that cycle doesn’t reverse itself.
Laser treatments like Laser Genesis and Laser Facial Rejuvenation (using the Excel V laser) work like this:
- Laser energy is delivered into the dermis — the exact layer where the fragmentation is happening
- This creates a gentle, targeted thermal response
- That response prompts fibroblasts to switch back on and lay down new, organised collagen
Put simply: sunscreen stops the cycle getting worse. Laser treatment gives fibroblasts a reason to start rebuilding — which is what’s needed to make progress against collagen that’s already fragmented.
A few things worth knowing:
- Non-ablative. Both treatments work without breaking the skin’s surface, so there’s typically little to no downtime.
- Done as a course. Collagen remodelling takes time, so sessions are usually scheduled at monthly intervals to keep fibroblasts active over several weeks.
- More than just collagen. The same treatment often improves redness, enlarged pores, fine lines and skin laxity too — because these issues tend to occur together.
- Can be combined with other treatments. Skin needling and chemical peels can also support collagen and texture. If pigmentation is also a concern, it’s worth reading how laser and chemical peels compare for pigmentation.
- Sunscreen still matters. It won’t undo existing damage, but it stops new rounds of breakdown from outpacing what a laser course is helping to rebuild.
- Results build gradually. Improvements tend to appear progressively over a course of treatment, not after one session.
Understanding the damage is the first step to treating it
Sun exposure ages skin through a coordinated attack: collagen-cutting enzymes switched on within hours, new collagen production suppressed at the same time, and the leftover fragments actively blocking repair. UVA adds to this on cloudy days and through glass — not just at the beach. And it’s happening well before it’s visible.
The good news: this process is well understood, and laser treatment works directly on it. Laser Genesis and Laser Facial Rejuvenation prompt fibroblasts back into action right where the damage is happening — paired with daily sun protection, that’s how real progress is made.
Curious how much sun damage is affecting your skin, and whether laser treatment could help rebuild your collagen? DermaCare can assess your skin at our Melbourne clinic and talk you through the right treatment for you.
Book a complimentary consultation.
