Light flow

Lou – Seamless Period Thong, Light Flow

Name: Lou – Seamless Period Thong, Light Flow
Brand: louloucup
SKU: L2190S
Availability: InStock

$29.90

From $23.62 for 5 ✨

Absorbs up to 15 ml — equivalent to 1.5 super tampons

OEKO-TEX Std 100 Class II · GOTS organic cotton lining

Tax included. Shipping calculated at checkout.

Ships within 48 hours Free shipping over $60 Free exchanges · Refunds less $5 return shipping

Save more with volume pricing

The more you buy, the lower the price

2 pairs $27.90 each

3 pairs $26.30 each

4 pairs $25.90 each

5 pairs $23.62 -21% ✨

* Applied automatically at checkout · Mix sizes & styles

💡 Tip: Mix sizes & styles in your cart — the volume discount applies to your total.

Seamless
Invisible
Leak-proof

Size	US	Hip (in)	Hip (cm)
XXS	0	31–32.5	79–83
XS	2	33–34.5	84–88
S	4	35–36.5	89–93
M	6	37–38.5	94–98
L	8	39–40.5	99–103
XL	10	41–42.5	104–108
2XL	12	43–45	109–114
3XL	14	45.5–47	115–120

Independently
lab-tested

OEKO-TEX
Std 100

Organic cotton
lining

Unretouched
photos

Recyclable
packaging

Audited
workshops

Why you'll love it

12h protection

15 ml — 1.5 super tampons

Side leak barriers

Absorbent side walls

Quality & transparency

Certified underwear for your health

OEKO-TEX certified fabrics with GOTS organic cotton lining in direct contact with your skin.

The entire panty is certified. Class II covers textiles in direct skin contact — the strictest safety standard.

Certificate no. 2026OK1834 — issued by AITEX

The layer touching your skin is made of GOTS certified organic cotton, the most demanding standard in organic textiles. No pesticides, no GMOs.

Our fabrics are safe, organic & certified We publish the independent lab report — Lab-tested · 25 ppb PFAS detection limit.

Read the report

Shipping & returns

🚚

US — Free shipping Ships within 48h (Mon–Fri) · Delivered in 3–7 business days

🌍

Canada — Free shipping on orders over $45 5–10 business days

↩️

Returns — 30 days Unworn, unwashed, in original packaging. Menstrual cups are not returnable.

Description

For the days that aren’t really your period — but aren’t nothing either.

Lou is a seamless thong, designed for the days you’d otherwise waste a pad on: the spotting before your period starts, everyday discharge, and the last two days when your flow has almost stopped. It holds 15 ml, the equivalent of about 1.5 tampons.

It’s a thong, so it does what a thong does — disappears completely, under jeans, under a fitted dress, under anything. No seams, no edges, nothing showing through.

Most people wear Lou alongside a heavier style: Mathilde or Liv on days one and two, then Lou for everything on either side. It also works as backup on cup days.

Available in sizes XS to 2XL.

Materials

Outer: 65% nylon, 35% elastane
Absorbent core: TPU and microfiber
Lining against your skin: organic cotton
OEKO-TEX® Standard 100 certified — certificate 2026OK1834, issued by AITEX
Lab-tested · 25 ppb PFAS detection limit
Designed in France since 2017

Care

Rinse in cold water right after wearing — cold water first, always.

Machine wash at 86°F (30°C) with the rest of your laundry. No fabric softener.

Air dry. Never tumble dry.

Size guide

Measure your hip at the fullest point. If you’re between sizes, size up.

Louloucup size	US size	Hip (in)	Hip (cm)
XS	2	33–34.5	84–88
S	4	35–36.5	89–93
M	6	37–38.5	94–98
L	8	39–40.5	99–103
XL	10	41–42.5	104–108
2XL	12	43–45	109–114

Our underwear fits true to size. If in doubt, measure at the fullest point.

Which style for your flow?

you are here

Light

Very light

Organic cotton on the outside too — all our underwear already has an organic cotton lining
Best-seller

Frequently asked questions

How long can I wear it?

Up to 12 hours for a regular flow, 6–8 hours for a heavy flow. It absorbs up to 15 ml — equivalent to 1.5 super tampons.

How do I wash it?

Rinse in cold water, then machine wash at 30°C / 86°F. Air dry. Avoid fabric softener and the dryer.

How many pairs do I need?

For a full cycle, we recommend 6–7 pairs: 4–5 to wear + 2–3 rotating while you wash. At 5 pairs you also unlock the maximum discount (-21%)!

How long does a pair last?

With proper care, about 5 years (200+ washes). A solid investment.

What if it doesn't work for me?

Exchange or refund within 30 days if unworn, unwashed, in original packaging. For a product defect: 30 days, even if worn.