Sleep lines on the face: what the pillow is actually doing

What a sleep line is, mechanically

The abstract of the 2016 Aesthetic Surgery Journal review by Anson and colleagues is direct about the mechanism. It states that compression, shear and stress forces act on the face in lateral or prone sleep positions, and that this is distinct from skin distortion caused by facial expression. The face is not moving. It is being loaded.

Reporting on the same review, Healio described the tissue as experiencing shear, compression and tensile mechanical forces during side or stomach sleeping, and noted that the resulting wrinkles appeared to occur at locations where the skin buckles to external forces. Buckling is the useful word. A crease forms where compressed skin has nowhere to go but fold.

This is why the problem belongs to pillow and position rather than to the skin surface. The input is load and duration. Anything that does not change the load or the duration is not addressing the mechanism.

How sleep lines differ from expression lines

The Aesthetic Surgery Journal abstract states that expression wrinkles and sleep wrinkles differ in aetiology, location and anatomical pattern. That is the whole distinction in one sentence: different cause, different place, different direction.

The Aesthetic Society press release accompanying the review adds a practical test. Expression wrinkles are caused by muscle contraction, so botulinum toxin can act on them. Sleep wrinkles are caused by mechanical compression, and the release states plainly that they cannot be eliminated using botulinum toxin. A line that does not respond to a muscle-targeted treatment is unlikely to be a muscle-driven line.

Where they appear, and which way they run

The Aesthetic Society press release reports that sleep wrinkles predominantly appear on the forehead, lips and cheeks. These are the regions that take the pressure when the head is turned onto a pillow.

On direction, the release states that most sleep wrinkles tend to be perpendicular to expression wrinkles. A forehead expression line runs horizontally, following the frontalis muscle; a sleep line in the same region tends to run across it. That crossing pattern is the most usable feature for telling the two apart on your own face.

The release also notes that sleep patterns can reinforce expression lines, so the two are not always cleanly separate. Where a sleep line and an expression line happen to share a direction, the loading adds to what the muscle already does.

Do they fade, and what the sources will not tell you

This is where the popular writing runs well ahead of the evidence. Everyone has seen a crease on waking that is gone by mid-morning, but we could not find an accessible source that puts a number on how long that takes, or at what point a crease stops resolving.

What is sourced is the direction of travel. The Aesthetic Society press release states that sleep wrinkles tend to worsen over time due to repetition combined with thinning of the skin and decreased elasticity as we age. Repetition plus reduced recoil is the stated mechanism for a transient crease becoming a settled one. No source we could read gives a timeline for that transition, so we do not give one.

What the dermatology bodies actually say

Given how confidently sleep position is discussed in beauty coverage, the silence of the main patient-facing dermatology pages is worth recording. The American Academy of Dermatology's public page listing eleven ways to reduce premature skin ageing does not mention sleep position, pillows or sleep creases at all. Its eleven items cover sun protection, self-tanner instead of tanning, smoking, repetitive facial expressions, diet, alcohol, exercise, gentle cleansing, washing, moisturiser and irritating products.

The Academy's public page on wrinkles likewise attributes them to ageing and to sun exposure, without reference to sleep. Cleveland Clinic's article on preventing wrinkles does not mention sleep position or pillowcases either, though it does discuss sleep duration.

The honest reading is that sleep position sits below the threshold these bodies use for public guidance, while sun exposure and smoking sit well above it. That does not make the mechanism wrong. It does mean anyone presenting a pillow change as a leading anti-ageing measure is going beyond what the dermatology bodies are prepared to say.

The silk pillowcase claim, checked

The claim is that a silk or satin surface reduces friction and therefore reduces facial creasing. It is asserted constantly by pillowcase retailers. We looked for the study behind it and did not find one.

GoodRx's physician-reviewed article on silk pillowcases addresses the wrinkle claim directly and states that there are no studies to support it, adding more broadly that there is not research to back up claims on the benefits of using a silk pillowcase. The study it does cite on silk and skin concerns atopic dermatitis, not wrinkles.

It is not that pillowcase fabric has never been tested against facial wrinkles. It has, once, with a different material. A double-blind, randomised, placebo-controlled trial reported by Healio put 61 women, average age about 47, on copper oxide-containing or ordinary pillowcases for eight weeks, and found reduced crow's feet wrinkle depth in the copper group at four and eight weeks by expert grading and 3D image analysis, with no change in controls. That result carries a real caveat: one of the researchers, Gadi Borkow, was chief medical scientist at Cupron Scientific, the copper textile company. It also says nothing about silk. So the position is that the fabric claim most people repeat has no trial behind it, and the one fabric trial that exists is small, short, industry-linked and about a different material.

What the review says actually changes the loading

Healio quotes the reviewers' conclusion that the only reliable way to minimise sleep wrinkles is to avoid facial distortion, while acknowledging that sleep position is extremely difficult to consciously change.

In The Aesthetic Society release the lead author, Dr Goesel Anson, states that if you can stay on your back, that is ideal, and notes that specialty pillows exist which are designed to help maintain that position and to minimise facial distortion during sleep. That is a description of the category, not an endorsement of any product, and no comparative trial of such pillows against facial wrinkles was found in this research.

Read as mechanics, the logic is simple and holds: a face that is not pressed against a surface is not being compressed, stretched or sheared. Everything else in this area is an attempt to make that loading gentler rather than to remove it, and the evidence for those attempts is thinner than the marketing suggests.

Common questions

Where this fits

This page is one row of a larger reference. The night-time symptom reference maps 50 night-time symptoms to the sleeping position associated with each, the likely mechanical cause, what published sources say to change, and the sign that means seeing a clinician instead. For 13 of those 50, no published source describes any bedding change at all.

Also relevant here: the other thing side-sleeping pressure does to that side of your face, side-sleeping support and where your face sits.

Sources

• Aesthetic Surgery Journal (Anson et al., Sleep Wrinkles: Facial Aging and Facial Distortion During Sleep) – abstract only
• The Aesthetic Society – press release on the sleep wrinkles study
• Healio – Researchers review wrinkles occurring through facial compression during sleep
• American Academy of Dermatology – 11 ways to reduce premature skin aging
• American Academy of Dermatology – Wrinkles
• Cleveland Clinic – Is Your Skin Aging? 7 Ways to Prevent Wrinkles
• GoodRx (medically reviewed) – 5 Ways a Silk Pillowcase Can Benefit Your Hair and Skin
• Healio – Pillowcases with copper oxide reduced crow's feet lines