Home/Scarlet | Period Underwear/Heavy Days Set
Scarlet Period The Heavy Days Bundle | PFAS-free Boyshort & High-Waisted Brief
Scarlet Period High-Waisted Brief | Leakproof, PFAS-free, Moderate Absorbency
Scarlet Period High-Waisted Brief | Leakproof, PFAS-free, Moderate Absorbency
Scarlet Period Boyshort – PFAS-free, Heavy overnight absorbency, Organic Cotton
Scarlet Period Boyshort – PFAS-free, Heavy overnight absorbency, Organic Cotton
Scarlet Period High-Waisted Brief | Leakproof, PFAS-free, Moderate Absorbency
Scarlet Period Boyshort – PFAS-free, Heavy overnight absorbency, Organic Cotton
Scarlet Period The Heavy Days Bundle | PFAS-free Boyshort & High-Waisted Brief
Scarlet Period High-Waisted Brief | Leakproof, PFAS-free, Moderate Absorbency
Scarlet Period High-Waisted Brief | Leakproof, PFAS-free, Moderate Absorbency
Scarlet Period Boyshort – PFAS-free, Heavy overnight absorbency, Organic Cotton
Scarlet Period Boyshort – PFAS-free, Heavy overnight absorbency, Organic Cotton
Scarlet Period High-Waisted Brief | Leakproof, PFAS-free, Moderate Absorbency
Scarlet Period Boyshort – PFAS-free, Heavy overnight absorbency, Organic Cotton

Heavy Days Set

Built for heavy days and longer nights.

$45.00 $51.00

Built for your heaviest days. Our best-selling leak-proof underwear, bundled and discounted. Full coverage, serious holding power, zero stress.

    Stylish and ultra-flattering fit
    Heavy Flow Absorbency
    Comfortable Stretch Fit
    Save $$ with Sets
Scarlet Period Boyshort (Heavy) (Size)
Scarlet Period High-Waisted Brief (Moderate) (Size)

✨ Complete Heavy Flow Protection: Includes 1 x Boyshort (holds up to 7 tsp) + 1 x High-Waisted Brief (holds up to 5 tsp).

✨ Leak-Proof, Quick-Dry Gussets: Both styles feature an ultra-absorbent gusset with a quick-dry polyester layer to lock in moisture and prevent leaks.

✨ Comfort-First Fits: Relaxed Boyshort for full coverage and a smoothing, supportive High-Waisted Brief - designed to move with you.

✨ PFAS-Free & Eco-Conscious: Thoughtfully designed with safe, sustainable materials for less waste and more peace of mind.

✨ Rinse in Cold Water: After wearing, rinse in cold water until it runs clear to keep them fresh.

✨ Machine Wash Cold: Toss them in with mild detergent (no bleach or fabric softener, please).

✨ Dry with Ease: Line dry or tumble on low - no need for extra care.

✨ Need more info? Please read our complete guide to caring for your period underwear here.

✨ Soft, Breathable Fabrics: Boyshort made from 95% GOTS-certified Organic Cotton + 5% Spandex; High-Waisted Brief made from a silky-soft blend of 45% Modal, 45% Cotton + 10% Spandex.

✨ Flexible, All-Day Comfort: Both styles include Spandex for gentle stretch that moves with you.

✨ Quick-Dry Leak Protection: Features built-in Polyester/PUL gusset to lock in moisture and keep you feeling fresh.

✨ PFAS-Free & Chemical-Free: No added toxic chemicals (independently lab-tested).

✨ Fit Note: Our underwear runs on the slightly smaller side - if you're between sizes, size up.

✨ Teen-to-Adult Fit: Our sizing is unique - please refer to both the numerical (e.g. 10, 12) and letter sizing (e.g. M, L) in our guide.

✨ Australian Sizing: We use AU sizes - international customers, check our Size Guide.

✨ Still Unsure? Contact us for advice. We love a chat!

Did you know that over 12 billion pads and 7 billion tampons end up in landfills yearly? By choosing Scarlet, you're supporting a more sustainable future - where self-care and sustainability go hand in hand.

✨ High-Quality, Safe Fabrics: Made with care, free from PFAS and harmful chemicals, and independently lab-tested for your safety.

✨ Eco-Conscious Manufacturing: Crafted with a focus on quality and reducing environmental impact.

✨ Recyclable Packaging: Minimal waste for a cleaner world.

✨ 1% for the Planet: Scarlet is proud to contribute to environmental stewardship with every purchase.

Size Chart

Size chart for Heavy Days Set
Scarlet Period The Heavy Days Bundle | PFAS-free Boyshort & High-Waisted Brief

Heavy Days Set

$45.00 $51.00
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For when your period is doing the most

The Hevy Days Set. Trust us - your white sheets will thank you.

Some days, you need backup that actually shows up. This duo is for your heaviest flows, longest days, and zero-spare-undies situations.

  • Designed for heavy days and overnight
  • Super soft, breathable fabric
  • No PFAS, no nasties, no sweaty regret
  • Feel and look like normal underwear
  • Zero leaks, zero worries
BUY NOW

Your Questions, Answered

How do they work?

Scarlet Period Underwear is designed to fit like normal underwear and features multi-layered leak-proof technology that wicks away moisture, absorbs fluid, and contains it to keep you dry and protected. 

The built-in leak-proof technology is harder working than disposable pads which means it can safely hold more liquid and last for years not hours. Loved by all; you can read some reviews.

Do I need to wear a cup, tampon, or pad too?

Depending on the absorbency you choose and the heaviness of your flow, you can wear our period undies on their own or as backup along with a Period Cup or tampon.

What does the absorbency level mean?

Super Light: Holds up to 1 teaspoon, equal to less than one regular tampon. Think of it as a new-age panty liner, great for spotting, light leaks and discharge. Try: Invisible Thong

Light: Holds up to 3 teaspoons, equal to 2 regular tampons or one pad. For light days, drips and discharge. Try: G-String or Bikini Brief in Light-Moderate

Moderate: Holds up to 5 teaspoons, equal to 3 regular tampons or 2 pads. For moderate days, or as extra defence on heavy days with our Period Cup. Try: High-Waist Brief or Bikini Brief in Moderate-Heavy

Heavy: Holds up to 7 teaspoons, equal to 4 regular tampons or 3 pads. Our heavy hitters are great worn on their own, day or night. Try: Boyshort or Period Cup

How do I wash them?

After use, rinse them in cold water (we recommend in the shower) until they run clear. Then, machine wash in cold water with mild detergent (no bleach!). Try our Laundry Bag to safeguard them on laundry day. Then just hang out to dry (the sunnier the better) or tumble dry on low - that’s it!

TIP: If it’s your first wear, pop them in the washing machine with your next cold cycle - washing them before wearing activates their absorbency even more.

What is your 30-day risk-free trial?

We offer a 30-Day Risk-Free Trial for first-time shoppers for one pair of underwear. If you’re unsatisfied or have sizing concerns, email us at support@scarletperiod.com.

How do I pick the right size for me?

We get it, sizing for bottoms is anything but standardised. Which is why this size guide will help break it down for you. Make sure to check both our numeric and letter sizing so no confusion (ie. our large is a 12).

When in doubt, feedback tells us better to size up. Still confused? You can also email us for help at support@scarletperiod.com.
★★★★★

"The modal cotton fabric is not only comfy, it’s better for the environment as the creation process doesn’t use as much water."

NEWS

★★★★★

"This Aussie-based label is putting the cool into period knickers."

Refinery29

★★★★★

"I was walking, catching up with friends and going to Pilates. All without a leakage scare in sight."

Beauty Heaven

Real advice for real cycle days