Spicule skincare: why these cosmetics sting and what happens to the skin

Spicules are microscopic, needle-like structures derived from the skeletons of certain marine sponges. When processed and incorporated into a cosmetic product, they create temporary microchannels in the stratum corneum: hence the tingling, and hence the nickname “microneedling in a bottle.”

The comparison helps explain the sensation, but it risks making people believe that a cosmetic containing spicules is equivalent to a standardized professional procedure. It is not. Above all: if a product stings, that does not automatically mean it is more effective.

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Why they sting

During massage, the microstructures come into contact with the skin’s most superficial layer. This causes tingling, a needle-like sensation, and sensitivity to touch which, depending on the product, may continue even after application.

This sensation makes the experience very convincing: feeling something seems to prove that the product is working. In reality, the sensation mainly confirms a mechanical interaction. On its own, it does not measure the clinical outcome.

It is the same misconception that makes a warming cream seem to work better than one that does nothing: we are evaluating sensory feedback, not the result.

Spicules and microneedling are not the same thing

The nickname “microneedling in a bottle” is effective, but it brings together two things that are only superficially similar.

Professional microneedling uses devices with needles of specific lengths and depths, selected according to the objective and the area being treated, along with hygiene, disinfection, and single-use protocols. The practitioner knows exactly how deep the needles are going and for how long.

Spicules are massaged over the skin’s surface in a cream or serum. They are distributed unpredictably, with their orientation and the pressure depending on how the product is applied and who applies it. Both techniques temporarily alter the skin barrier, but the degree of control is very different.

The practical consequence is this: with microneedling, the practitioner determines the variable; with spicules, you determine it without realizing it, and it changes with every application. This is not a reason to avoid them; it is a reason not to consider them the at-home, cheaper version of an outpatient procedure.

Active-ingredient penetration

The skin barrier deliberately limits the entry of many substances: that is its job. Experimental studies show that spicules can increase the penetration of molecules that would otherwise have difficulty crossing the skin on their own.

In 2025, a study on an antimicrobial peptide observed increased penetration when the peptide was combined with sponge spicules. These are interesting findings for delivery technology, but they do not demonstrate that any serum containing spicules makes any active ingredient effective.

This is the distinction I always make: a delivery system demonstrates something about that specific active–vehicle pair, not about the entire category. The same caution applies to high-molecular-weight active ingredients, which I wrote about in relation to PDRN.

Size changes everything

There is a 2019 study that, in my view, should be read by anyone who talks about spicules as though they were a single category.

The researchers prepared three versions of the same cream, changing only the size of the spicules: whole, broken, and powdered. The whole spicules, approximately 177 microns long, produced the highest permeation of a model protein, but they also caused irritation, pain, and redness. The broken spicules achieved only slightly lower permeation, with no statistically significant difference, and substantially better tolerability. These were the ones selected for the human phase.

In other words: two products that both claim to contain “sponge spicules” can behave completely differently on the skin, and the difference lies not in the ingredient but in the processing, which no label explains. This is why judging the entire category as a whole, either positively or negatively, makes little sense.

What the first cosmetic studies show

In 2025, a system with nano-encapsulated spicules was evaluated in a single-arm clinical study, examining parameters such as absorption, pores, texture, wrinkles, and pigmentation. The field is therefore moving beyond experimental models alone toward evaluations in humans, and that is real progress.

Questions remain about the number and size of the spicules, their distribution, dose, frequency, and comparison with formulas that do not contain the same technology. A single-arm study—that is, one without a control group—says much less than it may seem. And a result obtained with a specific system does not automatically apply to the entire category.

“Tingling must not become the new measure of effectiveness.”

Sensitive skin and combining them with other active ingredients

Because the principle involves temporarily altering the skin barrier, extra caution is needed with sensitive skin, irritated skin, active dermatitis, or inflamed acne. Combining them with retinoids, acids, or other potentially irritating ingredients should also be carefully considered: if you increase penetration, you also increase the penetration of whatever causes irritation.

If persistent burning, swelling, or significant redness occurs, that is not a sign that the product is working. It is a sign that this product, on this skin, is doing too much.

In 2025, an editorial published in the Journal of the American Academy of Dermatology drew attention to the potential risks of silica spicules in cosmetics intended for home use. This is an important signal, and it should be understood for what it is: not a condemnation, but a reminder that innovation and safety assessment must advance together.

My take

Spicules genuinely interest me because they address the most concrete limitation of topical cosmetics. But a technology that increases penetration expands opportunities while also increasing the need to know precisely what we are making penetrate, in what quantity, and into which skin.

I would always assess the complete formula, concentration, directions for use, and tolerability. And I would be wary of any product that uses the sensation as its main selling point: when sensory experience becomes the proof, it usually means the real evidence is limited.