Your skin carries cells that stopped working but never left

Some of the cells in your skin are no longer doing their job — and they are not going anywhere. Researchers call them senescent cells. The beauty press calls them zombie cells.

A healthy skin cell divides, works, and eventually makes way for a new one. A senescent cell does something different. It stops dividing, resists the signal to clear itself, and stays put.

That would be harmless if it stayed quiet. It does not. A senescent cell keeps secreting signalling molecules — inflammatory messengers that tell neighbouring healthy cells to behave badly too.

They accumulate slowly. In young skin they are cleared efficiently. From roughly the mid-thirties onward, clearance slows and the population builds.

Why this matters for how skin looks

The visible signs we treat as ageing are downstream of cellular housekeeping. Three consequences stand out.

Collagen breaks down faster than it is built. Senescent fibroblasts stop producing collagen and start producing the enzymes that degrade it. The result is loss of density and definition rather than surface lines.

Low-grade inflammation becomes constant. The inflammatory signalling is persistent and mild — not redness you would notice, but a background state that keeps the skin from settling.

The barrier repairs more slowly. Cell renewal depends on healthy cells being available to divide. When a growing share of them cannot, recovery after sun, cold or a treatment takes longer.

This is why a routine that worked at 35 can stop delivering at 50. The actives have not become less effective. The tissue responding to them has changed.

Senolytics work on a different question

Conventional anti-ageing actives ask healthy cells to do more. Senolytics ask dysfunctional cells to leave.

Retinol accelerates renewal. Vitamin C protects against oxidative damage. Peptides signal for collagen. All three are addressed to cells that are still capable of responding.

Senolytics take the opposite approach. They aim to selectively clear the cells that have stopped responding, so the healthy population has room and quieter conditions to work in.

The term came out of longevity research, not cosmetics. It moved into skincare because skin is the most accessible tissue in the body — and the one where the results are visible.

In practice the two approaches are complementary. Clearing dysfunctional cells does nothing on its own if there is no collagen stimulus alongside it.

The plant compounds behind the category

Most senolytic ingredients in cosmetics and supplements today are plant flavonoids. Two names come up repeatedly.

Fisetin is a flavonoid found in strawberries, apples and persimmons. It has been studied for its selective effect on senescent cells and is now a standard inclusion in longevity supplement formulations.

Quercetin appears in the same conversation, usually in combination rather than alone.

Alongside them sit two adjacent mechanisms that often share a formula:

• NAD⁺ support. NAD⁺ is the coenzyme that powers cellular energy production and DNA repair. Levels decline with age, and replenishing precursors is a parallel strategy to clearing senescent cells.
• Plant exosomes and stem-cell extracts. These carry signalling molecules intended to stimulate the skin's own regenerative activity once the dysfunctional cells are reduced.

A word on evidence. Much of the senolytic research is preclinical — cell culture and animal models. Human trials exist but are early, and results in a supplement do not transfer automatically to a topical. The mechanism is well characterised; the size of the cosmetic effect is still being established.

Where to find this approach in our selection

Three products in our range work on senescent cells or the mechanisms around them. Two are Swiss.

NIANCE Epigen9 is the most direct expression of the category we carry. It is sold as a defined course rather than an open-ended jar — four sealed airless vials used over 28 days. That format suits the mechanism: a concentrated intervention, then a return to maintenance care.

NIANCE Epigen12 takes the same thinking oral. NAD⁺ precursors and resveratrol target cellular energy and DNA repair rather than the skin surface.

Clinique La Prairie ENERGY is not a skincare product, and we would not position it as one. It is worth knowing about here because fisetin — the most studied plant senolytic — sits inside its formula, alongside beta-glucans for immune support.

Building a routine around it

A senolytic course is an intervention, not a replacement for daily care. It works best with a stable routine on either side of it.

1. Before. Establish a routine you can keep. Cleanser, a treatment serum, day protection, night repair. If your barrier is compromised, settle that first — ceramides and beta-glucans, not actives.
2. During the course. Run Epigen9 over its 28 days alongside your usual cleanser and creams. Do not start a second new active in the same month, or you will not know what did what.
3. After. Return to maintenance. This is where encapsulated retinol, vitamin C and multi-weight hyaluronic acid earn their place — the healthy cell population now has better conditions to respond in.

The pairing that makes sense for most people is one course, then six months of consistent maintenance, rather than continuous high-intensity treatment.

If you are over 45, or you have noticed that a routine which used to work no longer does, this is the point in the year to consider it. Autumn is when Swiss skin recovers from summer and before winter demands more.

What we can and cannot tell you

Senolytics are a genuinely new direction, and that is worth saying plainly rather than overselling.

What is established: senescent cells exist, they accumulate with age, and they secrete inflammatory signals that affect the tissue around them. This is well-documented biology.

What is still developing: how much of the laboratory effect translates to a cosmetic product applied to the face, and over what timescale. Manufacturer studies are encouraging but are not independent trials.

These are cosmetic and supplement products. They support the appearance and comfort of the skin. They are not medical treatments, and nothing here is a substitute for advice from a doctor or dermatologist.

If you would like help deciding whether a senolytic course fits what your skin is actually asking for — or whether your money is better spent elsewhere in your routine — write to us. Our team in Lausanne answers personally, and we will tell you when the answer is no.

Ask a BeautyLion Expert