“The greatest obstacle to knowledge is not ignorance, but the illusion of knowledge,” wrote American historian Daniel J Boorstin. It’s a phrase I return to often, a reminder of the importance of questioning what we think we know, especially useful when your job revolves around health and beauty.

Because even after years of writing, I still make skincare mistakes. Sometimes I combine the wrong actives. Other times, I copy a viral routine that clearly wasn’t designed for my skin. All of which has taught me that cosmetics aren’t entertainment; they’re part of our health and that knowledge, not novelty, should guide them.

If you’re someone who loves beauty as much as I do, you’ve probably had moments when your skin just… stalls. The products promise results, yet nothing seems to change. According to Arkaitz Felices, cosmetologist and director of Care, representatives of Reviderm in Spain, this isn’t always the fault of your products. Sometimes, it’s your skin. “If you notice that a product that works on people with a skin type and needs similar to yours has no effect on you, it is a clear clue that there may be an imbalance in the dermal extracellular matrix (ECM),” that is, the structural framework that facilitates cellular communication and the effectiveness of cosmetic active ingredients.

Felices suggests learning to distinguish between routines that simply need time and those that have hit a dead end. Some effects, such as hydration, are visible in a few days: the skin recovers volume, fine wrinkles due to dehydration are attenuated and the tissue appears more elastic and fresh.” Others, such as collagen production, cell turnover, or fading hyperpigmentation, are slower and depend on internal metabolic processes. “Results in these areas can take several weeks and vary by person.”

When a routine is genuinely off, the clues are obvious. “Irritation, redness, itching or inflammation are unmistakable signs that the skin is stressed or assaulted.” In those cases, stop, focus on repairing the barrier and restore balance before reintroducing actives. “When it comes to caring for our body’s most extensive and sensitive organ, the shortest route is not to ask ChatGPT, but to rely on qualified professionals who understand the science behind each skin.”

Skincare mistakes you may be making

Skipping proper cleansing“Pretending that a cosmetic acts on uncleaned skin is like serving dinner on dirty breakfast dishes,” says Felices, who considers cleansing the foundation of any routine. He recommends a thorough evening cleanse that removes oil-based impurities such as makeup and sunscreen, then water-soluble residue. A gentle enzymatic exfoliation can follow to clarify, smooth texture and improve receptivity, without aggressive renewal.

Forgetting photoprotection

Skipping SPF—or applying it in the wrong order—undoes progress. UV exposure drives pigmentation and premature ageing. Felices points out that applying sunscreen before other treatments have absorbed reduces its effect. A broad-spectrum filter should sit at the end of the daytime routine.

Layering products out of order

Texture hierarchy matters. Lightweight toners, serums and water-based treatments should be applied before creams or richer textures. “This is because thicker products act as a barrier and impede the penetration of subsequent cosmetics.”

Lacking consistency

This is non-negotiable. “Continuous and disciplined use is needed for weeks or months for the skin’s biological processes to respond,” says Felices. Constantly switching or quitting early makes real improvement hard to see.

Ignoring usage directions

Leaving a mask on all night doesn’t maximise benefits. Lab directions aren’t arbitrary; they’re based on studies that determine optimal exposure. With cellulose or biocellulose masks, there’s a point at which most hydration and actives have already transferred. Beyond that, the flow can reverse and the mask may begin to reabsorb moisture, reducing the benefits.

Mixing actives without a plan

More isn’t better. Overloading can weaken the skin barrier. “The skin microbiome is altered and inflammatory outbreaks, redness or flaking may appear. The key is to simplify the routine, space out treatments and remember that, in advanced cosmetics, efficacy does not depend on quantity, but on balance and personalisation.”

How to combine actives safely

If you’re unsure how to pair products, Felices offers this guide: