Sleep Short - Super Heavy Flow
Sleep short boxer style period underwear
Close up Grey sleep short boxer style period pants with stitching detail
Sleep Short - Super Heavy Flow
Sleep Short - Super Heavy Flow

Sleep Short - Super Heavy Flow

Regular price £32.95
Tax included. Shipping calculated at checkout.

These comfy Sleep Short style period undies are built with super absorbency to keep you protected all night long. With a protective layer offering extra coverage from front to back, you can rest assured you'll be protected from stained sheets and midnight leaks!

Our super-heavy Sleep Shorts hold up to 5 tampons worth (that's our most absorbent yet!)

  • Classic, comfortable cotton
  • Holds 5 tampons' worth or 25-30ml
  • Wear all night on super heavy flow
  • For periods, leaks & incontinence
  • Protection layer from front to back
  • OEKO-Tex certified materials

🍃 Bleed Green: Each pair of period pants replace 200+ disposables from going to landfill, reducing your waste by 99.5%

🤝 Giving Back: For every purchase, we give back to a girl in need. Find out more about our #ByYouForHer giving back scheme here

We offer free shipping on all UK orders and free shipping on International orders over £75.
For same-day dispatch and next day delivery, please place your order before 1pm.
All orders are dispatched from our UK warehouse using trusted couriers such as Royal Mail, DHL and DPD. 
Think our period pants sound too good to be true? Take them on a risk-free trial for 60 days!

If our undies don't work as promised, let us know within 60 days and we'll refund you, no questions asked. The 60-day risk free trial applies to one worn pair of undies only. Refunds will be paid to the original payment method that was used to place the order.
🚿 Rinse after use.
🧽 Machine wash on 30-40 degrees.
 🍃 Hang to dry or dry indoors on a radiator.
⚠️ Do not use fabric softener or bleach. No tumble drying.
And that's it! Your FLUX Undies are ready to wear again!

Our Period Pants Are:

Sustainably Manufactured

We only use eco-friendly materials that are sustainably manufactured

Vegan and Cruelty-Free

Made from natural materials and never with animal materials or testing

Free From Nasties

Certified safe for skin and free from toxins, chemicals and fragrances.

60-Day Money Back Guarantee
How They Work

Our period pants absorb up to 5 tampons' worth of liquid, yet they look and feel just like regular undies.

Our built-in tech works like this:

1. Top layer wicks moisture away from the surface quickly, to keep you dry

2. Our middle layers absorb your blood and lock in your flow

3. The bottom layer pushes liquid back up and keeps you leak-free

It's simple. Just wear, wash and reuse.

Blood, Sweat, Whatever.

Three layers of fabric absorbing liquid showing how period pants work

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Customer Reviews

Based on 38 reviews
Anonymous (Wanstead, GB)
Flow: Super Heavy
Products used: FLUX Undies, obvs!, Menstrual cup
These are good

No more waking up in a pool of my own blood. It's less goth but also less laundry.

EmmaJ (Nottingham, GB)
Flow: Super Heavy
Products used: FLUX Undies, obvs!, Menstrual cup
So comfortable!

Really comfortable and no leakage.

Jade M (Dunfermline, GB)
Flow: Super Heavy
Products used: FLUX Undies, obvs!, Cloth pads

I don't know why I waited this long to get this. I use this every night I have a my period and have just bought two more. It's super comfy.

I'm also normally a size 12 and so bought that size. Perfect fit. Absolutely highly recommend this product!

S.Y. (Singapore, SG)
Flow: Heavy, Moderate
Products used: Disposable pads
Peace of mind on long haul flight

I recently wore this on a long haul flight. I was worried because the flight was meant to be on the heaviest day of my period, so after reading rave reviews about the FLUX Sleep Short, I decided to give it a go (leap of faith after a bad experience with a different brand of period pants). I changed into them about 3 hours into the 13 hour flight and it kept me leak-free, dry and comfy for the remaining 10 hours. I changed out of them once I landed as it was starting to feel a bit "full" by then and put them in a ziplock bag. Really glad I bought these and will be wearing them to sleep in the future and will be buying the others to use during the day!

saskia vanpeene (Fulham, GB)
Flow: Heavy, Moderate
Products used: FLUX Undies, obvs!, Disposable pads
perfect for sleeping & sport

the fit is good, snug & comfortable, shape is simple and looks as promised.
with very Hight absorption it is great to sleep or for those with high flow.
i love that the absorption pad goes up the whole back: again perfect for sleeping, sitting/laying in weird position or for sports without worry!
would love more colours for this

Lauren (Sheffield, GB)
Flow: Heavy, Moderate
Products used: FLUX Undies, obvs!, Tampons, Cloth pads, Menstrual cup
Heavy flow Shorts

Brilliant, no leaks. Agree with others that sizing is on the small side.