Is the friction difference between silk and cotton actually measurable?

Yes. Silk's smooth, flat fiber structure has a lower coefficient of friction than cotton's rougher, more textured weave, which is a physical property that can be tested — it's not just a marketing claim.

Does the mulberry silk grade matter for these benefits?

Yes — momme weight and weave quality affect how smooth and durable the surface actually is. Silkhouse uses 22 momme mulberry silk, dense enough to keep its smoothness wash after wash instead of thinning out.

The Science

Silk Pillowcase Hair Benefits: What Actually Happens While You Sleep

See the difference →

It Comes Down to a Measurable Difference in Friction

The coefficient of friction between hair and fabric is what determines how much your strands catch, bend, and rub during eight hours of movement. Cotton's woven fibers create meaningfully more surface drag than silk's smooth, flat protein filaments, which is why the same amount of tossing and turning produces very different results depending on what's under your head.

Three Real Effects: Less Breakage, Less Frizz, More Retained Moisture

Lower friction means fewer cuticle-layer micro-abrasions, which translates to less breakage over weeks and months. It also means hair keeps its styled shape longer instead of frizzing from mechanical disruption, and because silk doesn't wick moisture out of hair the way absorbent cotton does, strands stay better hydrated by morning.

      "None of this replaces a good hair care routine — it protects it. Silk simply removes eight hours of unnecessary mechanical stress that cotton adds to whatever your hair already has going for it.
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Fabric	Surface Friction	Overnight Moisture Loss
Cotton	High	Significant
Synthetic Satin	Moderate	Some
Pure Silkhouse Silk	Low	Minimal

Silkhouse silk pillowcase and the science of hair friction

A Passive Upgrade That Works Every Single Night

You don't have to remember to use it correctly or apply it in a specific order. A pure Silkhouse silk pillowcase, Oeko-Tex certified, works simply by being what you sleep on — turning eight otherwise-neutral hours into eight protective ones.