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Soiea The Mulberry Silk Collection
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Let's be honest about what the science says

The science, honestly.

There is no peer-reviewed study of a mulberry silk pillowcase on hair, wrinkles, acne or skin moisture. Much of what this market calls science is brands testing their own products, unpublished. So we read the studies themselves, graded every claim, and wrote down only what holds up.

Research checked against primary sources on 25 October 2026. Sources at the foot of the page.

The short version

Every claim graded the same way. Established: standard, replicated facts. Good evidence: solid data on the exact property. Guidance: expert advice or a mechanism, without trials. Not shown: nothing found, or the best evidence points the other way.

Made mostly of fibroin. The sericin gum is washed out before weaving.12

A natural protein fibre, made mostly of fibroin.

About 11% of its weight, against 0.4 to 0.8% for polyester.3

About 11%, against under 1% for polyester satin.

On moisture from the air, silk holds as much as cotton or a little more.3 One small old study suggests cotton takes up liquid sweat faster.4

We don't say this.

UK and US dermatology guidance suggests satin or silk to cut overnight friction.56 No trial has tested it.

A smooth surface for your hair to move across while you sleep.

The one independent study that tested both against skin found no clear difference.8

We don't say this.

Sleep lines come from pressure. No study has tested a fabric.9

Sleeping on your back helps most.

No benefit shown in the trials that exist.1214

We don't say this.

No test of plain woven silk supports any of these, and silk proteins are documented allergens in rare cases.16 The only sleep temperature study we found used silk-filled quilts, not pillowcases.21

We don't say this.

What silk is

Mulberry silk comes from silkworms fed on mulberry leaves. Each cocoon is reeled as a single continuous filament, so there are no short fibre ends on the surface. Short-fibre "spun" silk is made more like cotton yarn.

Raw silk is two proteins. Fibroin is the fibre itself. Sericin is the gum that holds the strands together, about 25 to 30% of the protein.1 Sericin is removed in degumming before smooth silk fabric is woven, so a finished pillowcase is mostly fibroin.2 Supplier to confirm

What this means

Silk is a natural protein fibre. There is no evidence that it "feeds" skin or that amino acids move from a pillowcase into it.

Moisture

Moisture regain is how much water vapour a fibre holds from the air, as a share of its dry weight. These are standard textile figures at 21°C and 65% humidity.3

Wool13 to 18%
Silk11%
Cotton7 to 11%
Nylon4 to 4.5%
Polyester0.4 to 0.8%

Bars show the middle of each range. Source: Coats, Know About Textile Fibres.

So silk does not absorb less moisture than cotton on this measure, a claim you will see often. It does hold far more than polyester satin. One small physiology study on clothing patches found cotton took up sweat faster than silk;4 it was not about pillowcases.

We found no independent test of how much night cream a silk pillowcase takes up, and no study of skin hydration on people sleeping on silk.

Hair

British Association of Dermatologists, 2023Patient guidance

"Sleeping on a satin or silk pillowcase will achieve the same goal of minimising friction." From the leaflet on caring for Afro-textured hair, which also suggests loosely plaiting or twisting hair at bedtime.5

American Academy of Dermatology, 2022Guidance

Satin or silk bonnets or pillowcases "may also reduce friction and preserve your hairstyle", in its curly hair tips.6

Both say satin or silk, and neither endorses a brand. No peer-reviewed study has measured hair sliding on a silk pillowcase against cotton. An independent hair-testing lab says its own work shows lower hair friction on silk, without publishing figures.7 The "43% less friction" figures elsewhere come from brands' own unpublished tests.

Nothing shows that any pillowcase prevents breakage, frizz, split ends or hair loss.

What we say

A smooth surface for your hair to move across while you sleep.

Skin and sleep lines

Sleep lines form where the face is pressed and folded into the pillow when you sleep on your side or front.910 A pillowcase does not change that pressure. Sleeping on your back helps most. One study of 100 women found the side they slept on was not linked to the side with more wrinkles, so even the pressure link is not simple.11

On friction against skin, the one independent study that tested silk and cotton side by side, with 19 volunteers, found no clear difference, and silk read slightly higher in most conditions.8 The silk in that test may not have been a pillowcase weave, but it is the best evidence there is.

What we say

Silk gives your face a smooth, soft surface to rest on. We don't claim it prevents wrinkles or creases.

Acne, eczema and allergy

Pillowcase acne trial, Wake Forest University40 adults · 12 weeks

Used a polyester and nylon "silk-like" fabric, not silk, against cotton. The silk-like fabric did no better.12 A 2023 trial of real mulberry silk was registered and has not reported.13

CLOTHES trial, UK300 children · 6 months · randomised

Specialist silk clothing added to standard care made no clinically important difference to eczema.14

No study shows a silk pillowcase resists dust mites, and silk proteins can, rarely, be allergens, mostly from silk filling rather than woven fabric.1516 Whatever your pillowcase is made of, wash it every week.

Momme, grade and OEKO-TEX

Momme

A weight. 1 momme is 4.34 g per square metre, so 22 momme is about 95.5 g/m².17 Higher momme means more silk per square metre and a denser fabric. It is not a grade of quality, and no study shows one momme is better for hair or skin.

Grade 6A

The top grade for raw silk yarn under China's grading standard.18 It rates the yarn, not the finished pillowcase. SOIEA's grade: XXX

Charmeuse

A satin weave with long floats on the face for a glossy surface and a dull back. It can be woven from silk, polyester or rayon, so "charmeuse" alone doesn't mean silk.20 SOIEA's weave: XXX

OEKO-TEX® Standard 100

A label for textiles tested for harmful substances, against a list of more than 1,000. Bedding sits in Product Class II, for direct skin contact. Certificates last a year and can be checked by number on the OEKO-TEX site.19 It is not an organic or environmental label. SOIEA's certificate: No. XXX

Silk or satin?

Satin is a weave, not a fibre. Most low-cost satin pillowcases are polyester. Both silk charmeuse and polyester satin are smooth filament fabrics, and no independent study shows silk beats satin for hair or skin.

The real differences: silk is a natural protein fibre; it takes up about 11% moisture from the air against under 1% for polyester;3 and polyester is made from fossil fuels. Choose silk because you love how it feels. That is reason enough.

Claims we don't make

UK advertising rules say a claim needs evidence before it is made, and health or beauty claims need trials on people.22 So you won't see these from us:

  • Prevents wrinkles, anti-ageing, or smoother skin by morning
  • X% less friction than cotton
  • Prevents breakage, stops frizz, prevents hair loss
  • Keeps skincare on your face, or keeps skin hydrated
  • Helps acne, eczema or sensitive skin
  • Hypoallergenic, antibacterial or dust-mite resistant
  • Regulates temperature or improves sleep
  • Clinically proven, sustainable or eco-friendly

Questions people ask

There is no peer-reviewed study of a mulberry silk pillowcase on hair, wrinkles, acne or skin moisture. What holds up: silk is a natural protein fibre, it holds far more moisture from the air than polyester satin, and UK and US dermatology guidance suggests silk or satin to cut overnight friction on curly and textured hair.

No study shows that. Sleep lines form where the face is pressed and folded into the pillow when you sleep on your side or front, and a pillowcase does not change that pressure. Sleeping on your back helps most.

No benefit has been shown. The only completed pillowcase trial used a polyester and nylon silk-like fabric, not silk, and it did no better than cotton. A trial of real mulberry silk was registered in 2023 and has not reported. Whatever your pillowcase is made of, wash it every week.

No test of plain woven silk supports that, and silk proteins are documented allergens in rare cases, mostly from silk filling rather than woven fabric. No study shows a silk pillowcase resists dust mites.

Not on moisture from the air. Silk takes up about 11% of its weight, against 7 to 11% for cotton, so it holds as much or a little more. It holds far more than polyester satin, at 0.4 to 0.8%.

The British Association of Dermatologists and the American Academy of Dermatology both suggest a satin or silk pillowcase to reduce friction on curly or Afro-textured hair overnight. Both say satin or silk, and neither endorses a brand, SOIEA included.

Sources

  1. Aad R, Dragojlov I, Vesentini S. Sericin protein: structure, properties, and applications. J Funct Biomater 2024;15(11):322. doi.org/10.3390/jfb15110322
  2. Zhu L, Lin J, Pei L, et al. Recent advances in environmentally friendly and green degumming processes of silk. Polymers 2022;14(4):659. doi.org/10.3390/polym14040659
  3. Coats. Know about textile fibres. coats.com
  4. Kosaka M, Ohwatari N, Matsumoto T, Otomasu K, Yamauchi M. Analysis of sweating through clothing materials due to ventilated sweat capsule method. Descente Sports Science Vol. 15. shinshu-u.ac.jp
  5. British Association of Dermatologists. Caring for Afro-textured hair, patient leaflet, July 2023. bad.org.uk
  6. American Academy of Dermatology. 6 curly hair tips from dermatologists, 30 June 2022. aad.org
  7. TRI Princeton. Everyone is talking about silk pillowcases. triprinceton.org
  8. Ramalho A, Szekeres P, Fernandes E. Friction and tactile perception of textile fabrics. Tribology International 2013;63:29-33. doi.org/10.1016/j.triboint.2012.08.018
  9. Anson G, Kane MA, Lambros V. Sleep wrinkles: facial aging and facial distortion during sleep. Aesthet Surg J 2016;36(8):931-40. doi.org/10.1093/asj/sjw074
  10. Sarifakioğlu N, Terzioğlu A, Ates L, Aslan G. A new phenomenon: "sleep lines" on the face. Scand J Plast Reconstr Surg Hand Surg 2004;38(4):244-7. doi.org/10.1080/02844310410027257
  11. Kotlus BS. Effect of sleep position on perceived facial aging. Dermatol Surg 2013;39(9):1360-2. doi.org/10.1111/dsu.12266
  12. Wake Forest University. Efficacy of silk-like bedding fabric pillow case in the treatment of acne vulgaris. ClinicalTrials.gov NCT00767104. clinicaltrials.gov
  13. Integrative Skin Science and Research. Assessment of the effects of silk pillowcases on acne prone skin. ClinicalTrials.gov NCT06142487. clinicaltrials.gov
  14. Thomas KS, Bradshaw LE, Sach TH, et al. Silk garments plus standard care compared with standard care for treating eczema in children (CLOTHES). PLoS Med 2017;14(4):e1002280. doi.org/10.1371/journal.pmed.1002280
  15. Vaughan JW, McLaughlin TE, Perzanowski MS, Platts-Mills TA. Evaluation of materials used for bedding encasement. J Allergy Clin Immunol 1999;103(2):227-31. doi.org/10.1016/s0091-6749(99)70495-1
  16. Johansson SG, Wüthrich B, Zortea-Caflisch C. Nightly asthma caused by allergens in silk-filled bed quilts. J Allergy Clin Immunol 1985;75(4):452-9. doi.org/10.1016/s0091-6749(85)80017-8
  17. Store norske leksikon. Momme. snl.no/momme
  18. Niu J, Hu Q, Xu J. Correlation between indicators of the electronic testing and the current test for raw silk. Advances in Engineering Research vol 136, 2017. atlantis-press.com
  19. OEKO-TEX. STANDARD 100. oeko-tex.com
  20. MFA CAMEO. Charmeuse. cameo.mfa.org
  21. Zheng Q, Yan F, Wang H, Ke Y. Effects of quilts on comfortable indoor temperatures and human thermal responses during sleep. Indoor Air 2022;32(9):e13122. doi.org/10.1111/ina.13122
  22. ASA and CAP. Substantiation for health, beauty and slimming claims. asa.org.uk