A factual side-by-side comparison of mulberry silk, cotton (Egyptian, percale, sateen), satin (polyester), and synthetic blends — based on textile-science data. No marketing fluff.
The 8-criterion comparison
| Criterion | 22-momme Mulberry Silk | Egyptian Cotton (sateen) | Satin (polyester) |
|---|---|---|---|
| Friction coefficient | 0.43 (lowest) | 0.75 | 0.55 |
| Hygroscopy (moisture wicking) | 11% (high — pulls sweat without staying damp) | 8.5% (high but stays damp longer) | 0.4% (none — synthetic) |
| Thermoregulation (range tolerated) | 15–30°C | 18–26°C (overheats above) | 20–24°C (poor) |
| Hypoallergenic | Yes — natural antibacterial, resists dust mites | No — dust mites thrive | No — synthetic, traps allergens |
| Lifespan (weekly use) | ~10 years | ~5 years | ~2–3 years |
| Cost / year (€100 pillowcase) | €10/year (long lifespan) | €8–12/year (cheaper but replaced more) | €10–15/year (high replacement) |
| OEKO-TEX availability | Standard for mulberry silk | Common | Rare for cheap polyester |
| End-of-life biodegradability | Yes — fully biodegrades in ~4 years | Yes — ~5 months | No — 200+ years if landfilled |
What this means for your skin and hair
For skin (cheek-side sleep, fine lines)
Cotton's friction coefficient (0.75) tugs at the skin every time you move during the night — creating "sleep lines" that, repeated over years, become permanent. Silk's 0.43 friction halves this effect. 43% reduction in friction is the figure cited in Yonzon et al. (J. Cosmet. Dermatol., 2020). Satin polyester is in-between (0.55) but worse on hygroscopy — it traps oil and serums against the skin instead of letting them stay on the skin.
For hair (frizz, breakage, brushed-out blowouts)
Hair is more sensitive to friction than skin. On cotton, hair grips and tangles; the morning shows it. On silk, hair glides — blowouts last, frizz drops by up to 80%, and split ends form slower. Polyester satin is OK in theory but the static charge it builds (synthetic fibers) actively damages curls and coils.
For sleep quality (temperature regulation)
Silk's natural hygroscopy lets it wick sweat without retaining moisture. In winter it holds body heat; in summer it stays cool. Cotton holds moisture longer (you feel damp). Polyester traps heat and sweat — the worst combination for deep sleep.
The verdict
For nightly use over 5+ years, 22-momme mulberry silk is objectively superior on every criterion except short-term cost. Cotton remains the best entry point if you cannot invest yet. Polyester satin is a marketing convenience — it lacks every functional property of real silk while costing nearly as much.
FAQ
Is satin the same as silk?
No. "Satin" refers to a weave (a glossy front face). It can be made from silk, polyester, nylon, or acetate. Most "satin pillowcases" on the market are polyester — they have none of silk's functional properties (hygroscopy, hypoallergenic, biodegradability).
Is silk hypoallergenic for sensitive skin and eczema?
Yes. Mulberry silk is naturally antibacterial, resists dust mites (the #1 allergen in bedding), and contains 18 amino acids shared with human skin — meaning the fibre doesn't trigger contact dermatitis the way some cotton finishes can. OEKO-TEX Standard 100 certification guarantees no harmful dye residues.
Will 22-momme silk overheat in summer?
No. The myth comes from thicker silks (25mm+). At 22mm with charmeuse weave, the fabric is thin enough to breathe but dense enough to wick sweat. Real-world: most users report better summer sleep on silk than cotton or polyester.
How does silk biodegrade?
Pure silk (protein fibre) decomposes in soil in approximately 4 years. Cotton (cellulose) decomposes in months. Polyester satin lasts 200+ years in landfill — it's effectively plastic.