Classic Boyshort - Heavy Flow
Boyshort style period underwear with elastic logo waistband
Boyshort style period pants with elastic FLUX Undies logo waistband
Boyshort style period pants with FLUX Undies logo waistband
Classic Boyshort - Heavy Flow
Classic Boyshort - Heavy Flow

Classic Boyshort - Heavy Flow

Regular price £27.95
Tax included. Shipping calculated at checkout.

Get comfy on your period with our leak-proof Boyshort period pants, featuring our classic logo elastic waistband full of stretch and softness. With our signature built-in tech that is moisture wicking, absorbent, and leak-proof, Boyshort gives you the ultimate comfort and protection during your period, day and night.  

  • For periods, leaks and incontinence
  • Holds Four Tampons' Worth / 20-25ml
  • Wear For Up To 12 Hours Leak-Free
  • Soft, Stretchy and Comfortable
  • Lightweight and Quick-drying
  • OEKO-Tex Certified Materials
  • Free From Toxins, Chemicals and PFAS/PFOA

Materials: Body95% TENCEL Modal 5% Elastane Gusset: Absorbent Blend, Breathable PUL Packaging: 100% Recycled and Recyclable Cardboard

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

🤝 Giving Back: For every purchase, we give back to someone in need. Find out more about our #ByYouForThem 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 174 reviews
Anonymous (Milton Keynes, GB)
Flow: Heavy
Products used: FLUX Undies, obvs!
Game changer

Absolute game changer, Iv only used these at home so far as it happened while I was home but I feel dry, No need to worry about changing sanitary products all the time and so comfy

E.S. (Birmingham, GB)
Flow: Heavy
Products used: FLUX Undies, obvs!, Menstrual cup
Very happy

At first I couldn’t see myself spending this much on underwear but now I'm buying more, they make the whole period experience much more comfortable. As the product information states I would size up for this particular style :)

Veronica B (Dublin, IE)
Flow: Super Heavy
Products used: Disposable pads

Great product. Only thing to be careful of is size. I'm a 16 plus (the Covid stone plus!) so went for 16/18 but band is a bit tight bearing in mind bloating etc. But other than that so comfortable compared to bulky pads.

Marina A. (Nicosia, CY)
Flow: Moderate
Products used: FLUX Undies, obvs!, Tampons
Very comfortable

I've worn these on my heavy day during night-time and while working from home during quarantine and I am very pleased with them! I haven't had any leaks, they are very comfortable and they don't smell! That being said, I cannot easily wear them outside the house because of the heavy padding, since I mostly wear thongs.

L. (Newport, GB)
Flow: Super Heavy, Heavy
Products used: FLUX Undies, obvs!, Disposable pads
Amazingly helpful

I'm a disabled transman who suffers from CFS. I grabbed the boy shorts after hearing about these undies on a youtube video and they have helped me out so much. Not only do they look good, but they are SO comfortable and the style of the undies has a very unisex vibe to them which helped combat my dysphoria <3
These undies really made my monthly so much more bearable, helped me not worry about my cycle and was really easy to use - my CFS thanks you FLUX!

E. (Oxford, GB)
Flow: Super Heavy, Heavy
Products used: FLUX Undies, obvs!
Another Great Purchase

I love these pants so much I have a collection of styles and absorbency types to see me through each period. I can’t recommend them highly enough. So much more comfortable than pads and tampons.