Skin Physiology 101: What's Actually Happening Under the Surface

Last night my boyfriend was helping his daughter cram for her sophomore physiology test, and I had one of those total girl-brain moments where the word just would not come to me. I knew what physiology was — twenty-two years into this career, it's basically my whole world — I just blanked trying to explain it out loud and ended up quietly double-checking myself. We've all been there.

But it got me thinking. I've spent 22 years working with skin. I see physiology every single day, I just don't always stop to name it. So I started thinking about how I'd explain it back — the skin's physiology, in plain terms. Because once you understand what's actually happening at the cellular level, skincare stops feeling like guesswork and starts feeling like science you can trust.

The Layers: Your Skin Isn't One Thing, It's Three

Your skin has three main layers, and each one has a different job.

The epidermis is the outermost layer — your skin's security team. It's made mostly of keratinocytes, cells that are constantly cycling: born at the base, pushed upward, and shed at the surface roughly every 28 days (a little slower as we age). This is the layer dermaplaning and gentle exfoliation work with — helping that turnover happen smoothly instead of getting sluggish and dull.

Below that sits the dermis, where the real structural work happens. This is home to fibroblasts, the cells responsible for producing collagen and elastin — the proteins that keep skin firm, bouncy, and resilient. This is the layer we're talking to every time we do microneedling or thermal rejuvenation.

Underneath it all is the hypodermis, a layer of fat and connective tissue that cushions and insulates.

The Cells: Tiny Factories with a Job to Do

Every one of those cells — keratinocytes, fibroblasts, melanocytes (your pigment producers) — is essentially a tiny factory. And like any factory, it needs power to run.

That's where mitochondria come in. You might remember them from biology class as "the powerhouse of the cell," and that description holds up. Mitochondria take nutrients and oxygen and convert them into ATP — usable cellular energy. Every bit of collagen a fibroblast produces, every bit of repair a keratinocyte performs, runs on that energy supply.

Here's the part I find genuinely fascinating: when cells have abundant energy, they do their jobs well — steady collagen production, efficient turnover, faster repair. When that energy is compromised — by UV damage, stress, inflammation, or just time — everything downstream slows down. That's the cellular story behind fine lines, sluggish healing, and tired-looking skin. It's not that your skin "gives up." It's that the factories are running low on fuel.

How This Shows Up in the Treatment Room

This is exactly why I've always believed that protecting skin on a cellular level is the real key to longevity — not chasing a quick fix on the surface.

LED red light therapy, like what we use in studio, works directly with this process. Specific wavelengths of light are absorbed by the mitochondria themselves, supporting that energy production so cells have more fuel to do their repair work. It's one of the few treatments that's genuinely working with your biology, not just on top of it.

Microneedling works with the dermis and those collagen-producing fibroblasts — creating a controlled signal that tells them to get back to work. Lymphatic drainage supports the whole system by helping the body clear out waste and inflammation so those cells aren't working in a congested environment. Every treatment I offer is really a conversation with a different part of this cellular process.

The Takeaway

Healthy tissue isn't random. It's the sum of billions of individual cells, each one powered and supported enough to do its job well. When I say healthy skin is a journey, this is what I mean — we're not chasing overnight change, we're supporting a system that's working for you every single day, whether you think about it or not.

Turns out, I didn't need a physiology textbook to understand this. I've been reading it in skin for 22 years.

Alicia