Our technology

How does it work?

Two years of work with a textile engineer went into creating underwear that absorbs menstrual blood for up to 12 hours, without any damp feeling, odor, or visibility under clothing. Here’s what’s inside and why it works.

  1. 01Materials
  2. 02Seamless
  3. 03In use
The three materials in a Smoon period panty: moisture-wicking, absorbent, waterproof

12 h

of protection, equivalent to 2 to 6 tampons depending on the model

3 materials

Seamless construction, with only the absorbent area doubled.layered

2 years of R&D

with a textile engineer, French and Italian materials

Step 01

Three materials, each with its own role

In the absorbent area, three technical materials are layered, from the skin outward. Hover over the diagram or cards to identify them.

Skin side

01 02 03 04

Clothing side

  1. 01

    Moisture-wicking fabric

    Against the skin. It wicks the flow toward the absorbent material and dries immediately, unlike a pad, which stays damp.

    What it changesNo feeling of dampness

    CompositionHydrophilamide, polyamide, elastane

  2. 02

    The absorbent material

    It holds back flow all day or all night, for up to 12 hours. Antibacterial, it prevents odors from developing.

    What it changesUp to 12 hours, zero odor

    CompositionPolyester

  3. 03

    The waterproof and breathable membrane

    Finally, it blocks leaks while allowing the water contained in the blood to evaporate thanks to body heat. No moisture buildup.

    What it changesZero leaks, without a stuffy feeling

    CompositionPolyester, polyurethane

  4. 04

    The main material

    It’s the underwear itself: soft and designed to move with you. Skin-like microfiber or organic cotton, depending on the range.

    What it changesComfort and invisibility

    CompositionPolyamide and elastane, or GOTS-certified cotton

Only the gusset area is made up of several layers. The rest of the briefs is not lined, which makes them twice as thin as other period underwear.

Close-up view

The materials, an absorption test, and the seamless finish, filmed up close.

In Stories

Technology at hand

The same principle, filmed in Story format, just like on your phone: the underwear turned inside out and stretched, with a close-up of the absorbent area. Press play—it lasts less than a minute.

Tap the screen to switch from one sequence to another.

Seamless edge of a carmine Smoon period panty, lifted by a hand

Step 02

Seamless, our signature style

Our panties are not sewn: the materials are heat-bonded. A technical choice that serves three purposes.

  • Even more comfortNo seams, no ridges: nothing rubs or leaves marks on the skin.
  • Invisible under clothingInvisible, seamless edges, even under leggings.
  • A membrane that has never been piercedA seam would pass through the waterproof membrane. Without a seam, the leak-proof barrier remains intact.

This is also why the panties should be washed at a maximum of 30°C: the heat-bonded seams are sensitive to heat.

View the seamless panties

Step 03

A day with

What happens between the moment you put it on and the moment you rinse it.

  1. In the morning01

    Put it on

    Like regular underwear. The absorbent area should fit snugly: it follows your movements and prevents leaks.

  2. During the day02

    The flow is drained, then absorbed

    The moisture-wicking fabric dries instantly, the absorbent fabric holds, and the membrane blocks. No moisture, no odor, nothing shows.

  3. Up to 12 hours03

    Day or night, without even thinking about it

    Equivalent to 2 tampons for a medium flow, 4 for a heavy flow, 6 for Hécate. During sports, at the office, or at night: it stays in place.

  4. In the evening04

    Rinse with cold water

    Until the water runs clear, then machine-wash at 30 °C with the rest of the laundry. It air-dries and is ready to go again.

Good to know

The panties can be worn alone or in addition to a cup or tampon. Never with a pad or panty liner: their adhesive makes the absorbent area useless. A fast, frequent flow may saturate them sooner than expected; in that case, change your panties or choose a more absorbent model.

Choose my absorbency level

Two ranges, one technology

The absorbent area is the same. What changes is the main material of the panties.

Microfiber

  • 80% polyamide, 20% elastane: lightweight, breathable, second-skin feel.
  • Up to 12 hours of protection.
  • Lightly shaping when first worn, it softens from the first day.
  • The widest choice of styles, absorbency levels, and colors.
View the microfiber range

Cotton

  • GOTS-certified organic cotton, soft and breathable, designed for sensitive skin.
  • Up to 8 hours of protection.
  • Gynaecologically tested and validated by a clinical study.
  • PFAS-free certified.
View the cotton range

No compromise on your health

What’s in contact with your skin several days a month deserves proof, not promises.

Certification

OEKO-TEX® STANDARD 100

All our French and Italian fabrics are certified in our name (certificates CQ 1285/1 and CQ 1285/2). None contain silver nanoparticles.

Learn more

Independent laboratory

PFAS-free

We commissioned an independent laboratory to test every textile material. Result: no PFAS detected, even at trace levels.

Test details

Cotton range

Gynecological examination and clinical study

Our certified GOTS organic cotton panties are tested under gynecological supervision and validated by a clinical study.

View the cotton range

Company

First B Corp-certified period underwear brand

A certification that evaluates the entire company: social and environmental impact, and transparency. We are also assessed by EcoVadis.

Our commitments

And to make it last

Four gestures, two to three years

The fabrics themselves absorb and limit bacteria: their effectiveness does not expire. Properly cared for and alternated with others, a pair of period underwear will last you two to three years.

  1. Rinse with cold waterAfter wearing, until the water runs clear. Never use hot water, as it will set the blood.
  2. A standard detergentNo Marseille soap, glycerin, or fabric softener: they clog the fibers and reduce absorbency.
  3. 30°C maximumIn the washing machine, in a mesh bag, with the rest of the laundry. The heat-sealed bonding does not like heat.
  4. Air-dryNever use a tumble dryer or radiator.

Your questions

Do I feel damp?

No. The material in contact with the skin wicks the flow toward the absorbent material and dries immediately. That’s the difference compared with a pad, which keeps the liquid on the surface.

What about odors?

The absorbent material is antibacterial: it prevents the bacteria responsible for odors from developing. And because the membrane is breathable, the water contained in the blood evaporates instead of causing dampness.

How long can I keep it?

Up to 12 hours in microfiber, 8 hours in cotton, depending on your flow. On heavy-flow days, change your underwear during the day or choose a more absorbent style: our guide will help you choose.

Can I wear it with a pad or panty liner?

No: glue would make the absorbent area useless. However, you can wear it alongside a cup or tampon on very heavy-flow days.

Why wash it at a maximum of 30°C?

Because our panties are heat-bonded, not sewn. The heat from a tumble dryer, radiator, or hot wash could damage the bonded seams. Rinse in cold water, machine wash at 30°C in a mesh bag, and air-dry: that’s all. Care guide.

How long does a pair of panties last?

It is the materials themselves that absorb and limit bacteria: their effectiveness does not expire. Like any underwear, it wears out over time. With proper care and rotation with others, it should last two to three years.

Where are they made?

Designed in Paris, our panties are made in Tunisia, in a factory renowned for its lingerie expertise and regularly audited for working conditions. The materials come from France and Italy.

You know how it works. All that remains is to try it.

Wear it, wash it, live in it for 60 days. If it’s not right for you, you’ll get a refund.

Our offer Satisfied or refunded