Savehra research
The science of what you sleep on.
8 hours a night. 2,900 hours a year. That is how long your hair, skin and face spend pressed against fabric. So we went through the university labs, sleep studies and fibre makers to find out what is best to sleep on.
Proof · Frizz
20x
a night, your pillowcase drags across your hair. Friction is what frizz is made of.
Cotton is short, twisty fibres with fuzzy ends that catch every strand. Modal is long, fine and even, so your hair glides.
Textile science review, Materials, 2022
Proof · Skin
0
sweat bacteria grew on modal's fibre family. Cotton grew three types.
Scientists grew real sweat bacteria on different fabrics. Cotton grew three types. Polyester grew the most.
Ghent University lab test, 2014
Proof · Face
70%
of the night, your face is pressed into your pillow.
Surgeons call the result sleep lines: creases made by your pillow, not your muscles. Rough cotton catches your skin and folds it. Smooth modal lets your cheek slide.
Aesthetic Surgery Journal, 2016
Proof · Hair
2,900
hours a year, your hair is pressed against your pillowcase.
Your shampoo, your serum and your salon visit get minutes. Your pillowcase gets a third of your life.
8 hours a night, every night
Proof · Softness
#1
softest of 100+ fabrics tested. It was modal's finest fibre.
Measured with sensors, not by touch. The more modal in a fabric, the softer it scored, and it stayed soft after washing.
Lenzing × Emtec softness study
Proof · Sleep
14min
faster to fall asleep in moisture-absorbing sleepwear than in cotton.
A sleep lab tracked people all night in different fabrics. The one that absorbed the most moisture put them to sleep fastest.
University of Sydney sleep lab, 2019
Meet the fabrics
Same bed. Three very different fibres.
Modal and cotton both come from plants. Silk comes from silkworms. How each fibre is built explains how it feels on your hair and skin.
The three fibres, side by side
| Compared on | Modal | Silk | Cotton |
|---|---|---|---|
| Made from | Beech trees, turned into a silky-smooth fibre | Thread spun by silkworms | Fluffy fibres from the cotton plant |
| Up close | Smooth, round and perfectly even | One long, smooth strand | Short and twisty, with tiny fuzzy ends |
| Thickness | 10 to 13 microns | 10 to 13 microns | 12 to 22 microns |
| Known for | Soft, cool, keeps its shape | Shiny and slippery | Classic and tough |
Morton & Hearle, Physical Properties of Textile Fibres, 2008 · BISFA terminology for modal fibres
6 times finer than a hair
A human hair is about 70 microns wide. A modal fibre is just 10 to 13.
Built to stay strong
Modal is defined by BISFA, the international fibre standards body, as a fibre that holds its shape when damp far better than ordinary viscose. That is what makes it soft and durable at the same time.
01 · Staying smooth
Rough fabric drags. Smooth fabric glides.
You change position around 20 times a night, and every move pulls your hair and skin across the fabric. A 2022 science review found rough, fuzzy fabrics create more rubbing. Modal's fibres are long, fine and even, with none of cotton's fuzzy ends.
How much fabric drags on skin
Higher means more rubbing · measured on 22 volunteers
Gerhardt et al., J R Soc Interface 2008; 5(28): 1317–1328 · D'Souza et al., Materials 2022
More than twice the rubbing
Researchers in Switzerland measured it on 22 volunteers: wet fabric dragged on skin more than twice as hard as dry fabric.
Where modal comes in
Modal draws moisture inside the fibre, so the surface against you stays on the dry, low-rubbing side of this chart all night.
02 · Staying fresh
Fewer odour-causing bacteria.
That slept-in smell comes from bacteria feeding on sweat in your fabric. Scientists at Ghent University in Belgium grew real sweat bacteria on different fabrics to see which ones they liked.
What grew on each fabric
- ViscoseModal's fibre family
- Nothing. None of the sweat bacteria tested grew.
- Cotton
- 3 types, including one linked to breakouts.
- Polyester
- The most growth of 3 types.
- Wool
- Almost every type tested.
Callewaert et al., Appl Environ Microbiol 2014; 80(21): 6611–6619
More labs agree
Innsbruck Medical University found wood-based fibres carried less bacteria than polyester and nylon. Germany's Hohenstein Institute also measured lower bacterial growth on wood-based fibres than on polyester.
How it works
Bacteria need moisture on the surface to grow. Wood-based fibres like modal pull that moisture inside the fibre, so there is less left for them.
03 · Staying dry
Modal soaks up the most.
Even when you don't feel sweaty, your skin releases moisture all night. Modal pulls it into the fibre itself, holding 11 to 13% of its own weight. Cotton holds 8.5%. That makes modal up to 50% more absorbent than cotton.
How much moisture each fibre soaks up
As a share of its own weight
ASTM D1909-13 · Morton & Hearle 2008 · Lenzinger Berichte 89 (2011)
Why you'll feel it
Moisture that goes into the fibre isn't sitting on your skin, so you wake up feeling dry instead of clammy.
Breathes better, too
Scientists knitted modal and cotton the same way at four tightness levels. Modal let more air through every single time.
Won't it dry me out?
No. Modal takes in water vapour when the air next to you gets humid and releases it again as the air dries. It evens out the air around you; it doesn't pull water out of you.
04 · Sleeping better
Stay cool. Fall asleep faster.
Feeling hot and sticky is one of the biggest reasons people toss and turn. Researchers at the University of Sydney tracked people's sleep all night in different pyjama fabrics. The fabric that absorbed the most moisture put people to sleep fastest.
Minutes to fall asleep, by fabric
Adults aged 65 and over · warm bedroom · measured in a sleep lab
Chow et al., Nat Sci Sleep 2019; 11: 167–178
14 minutes faster
In the over-65 group, the most moisture-absorbing sleepwear cut the time to fall asleep by 14 minutes against cotton.
Where modal fits
Modal soaks up to 50% more moisture than cotton, putting it firmly on the moisture-absorbing side of these results.
05 · Softness that lasts
Soft out of the bag. Soft for good.
Lenzing, the Austrian company behind Lenzing Modal, teamed up with German instrument maker Emtec Electronic to measure softness with sensors that listen to a fabric instead of relying on touch.
-
100+
fabrics tested, from cotton and cotton blends to modal and MicroModal.
-
#1
MicroModal ranked softest of every fibre tested. The more modal in a fabric, the softer it scored.
Modal against cotton
- Stretch before breaking
- Modal 12 to 16%, so it bends and moves with you. Cotton 6 to 10%.
- When damp
- Modal keeps its shape. Cotton holds water and wrinkles easily.
- Feel
- Modal is silky, cool and drapes smoothly. Cotton is crisp and can feel stiff.
Lenzing × Emtec Electronic softness study · Morton & Hearle 2008
Skin · Clean contact
A cleaner place to rest your face.
Oil, sweat, skin cells and hair products build up on a pillowcase, and your face rests on all of it, night after night. A fabric that stays fresher and rubs less is simply a better place to sleep.
Cotton grew three types
In the Ghent University test, cotton grew three types of sweat bacteria. Modal's fibre family grew none of the types tested.
Less rubbing, too
Modal's smooth, even fibres glide over skin instead of scuffing it, so your cheek slides instead of rubbing every time you turn.
Callewaert et al., Appl Environ Microbiol 2014
Skin · Sleep lines
Your face has a night shift.
Plastic surgeons writing in Aesthetic Surgery Journal found that sleep lines are different from expression lines. They are caused by your face being pressed, pulled and dragged against the pillow, not by your muscles.
How you spend the night
Share of sleep time in each position, averaged across studies
Anson, Kane & Lambros, Aesthetic Surgery Journal, 2016
70% of the night
Side and stomach sleeping together put your face against the pillow for most of the night.
Every turn drags your skin
On a rough surface, skin catches and folds instead of sliding. A smooth pillowcase lets your cheek glide.
Skin · Sensitive skin
Gentle enough for sensitive skin.
Dermatologists at University Hospitals Case Medical Center ran a randomised crossover trial. Thirty people, including people with eczema-prone skin, slept in wood-based lyocell, modal's sister fibre, and in cotton, one week each. The wood-based fibre was preferred for softness, temperature control, moisture control and wrinkle resistance.
How fine each fibre is
Coarse fibres over about 30 microns are linked to the prickle feeling on skin
Love & Nedorost, Dermatitis 2009 · Yao et al., J Am Acad Dermatol 2011 · Morton & Hearle 2008
4 wins over cotton
The authors concluded the wood-based fibre was superior to cotton in many performance characteristics.
Balanced, not soggy
A study in the Journal of the American Academy of Dermatology concluded that a fabric's ability to absorb moisture may be a key factor in how hydrated skin stays overnight.
Six habits for better mornings.
Small changes-
Wash it weekly.
Oil, sweat, skin cells and products build up on your pillowcase. Modal is machine washable, so keeping it fresh is easy.
-
Let skincare sink in.
Give your serums and moisturiser a few minutes to absorb before your face meets the pillow.
-
Keep hair products off your face.
Tie hair back loosely so oils and styling products don't sit against your skin all night.
-
Sleep on smooth.
A smooth modal pillowcase lets your hair and cheek glide when you turn.
-
Keep it cool.
A cooler room and breathable bedding help skin stay calm and help you sleep more deeply.
-
Flip and switch.
Flip your pillow mid-week, and keep a second pillowcase ready so there is always a fresh one.
The verdict
The Savehra scorecard.
Modal is the only fabric of the three that scores Excellent across the board. That is why we chose it.
Modal, silk and cotton, side by side
| Compared on | Modal | Silk | Cotton |
|---|---|---|---|
| Smooth on hair and skin | ExcellentFine, even fibres | Excellent | Fair |
| Stays fresh | ExcellentFibre family grew no tested bacteria | Good | Good |
| Soaks up moisture | Excellent11 to 13% | Excellent | Good |
| Breathability | ExcellentBeat cotton in every knit test | Good | Good |
| Sleep comfort | Excellent | Excellent | Good |
| Softness | Excellent#1 of 100+ fabrics | Excellent | Good |
| Easy care | ExcellentMachine washable | Fair | Excellent |
Go deeper
Read the full reports.
Every number on this page comes from the studies, standards and fibre research in our two reports.
Sources
- Anson G, Kane MAC, Lambros V. Sleep wrinkles: facial aging and facial distortion during sleep. Aesthetic Surgery Journal. 2016.
- ASTM D1909-13. Standard tables of commercial moisture regains for textile fibers.
- Callewaert C, et al. Microbial odor profile of polyester and cotton clothes after a fitness session. Appl Environ Microbiol. 2014;80(21):6611-6619.
- Chow CM, et al. The impact of sleepwear fiber type on sleep quality under warm ambient conditions. Nat Sci Sleep. 2019;11:167-178.
- D'Souza B, et al. Factors affecting the tribological interaction between human skin and textile materials. Materials. 2022;15(6):2184.
- Gerhardt LC, et al. Influence of epidermal hydration on the friction of human skin against textiles. J R Soc Interface. 2008;5(28):1317-1328.
- Lenzing and Emtec Electronic. A new definition of softness in textiles. Textilegence.
- Love WE, Nedorost ST. Fabric preferences of atopic dermatitis patients. Dermatitis. 2009;20(1):29-33.
- Morton WE, Hearle JWS. Physical Properties of Textile Fibres. 4th ed. Woodhead Publishing; 2008.
- Yao L, Li Y, Gohel MD, Chung WJ. The effects of pajama fabrics' water absorption properties on the stratum corneum. J Am Acad Dermatol. 2011;64(3):e29-36.
So we're fixing this.
One pillowcase at a time. Smooth modal, built around the science on this page.