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    Black period underwear (medium-heavy flow)

    Unit price  per 
    Black period underwear (medium-heavy flow)

    Not sure which size is you? Click here for our comprehensive size guide.


    Simply wear, wash, and repeat.  Ultra comfortable, super flattering.

    • We've got you covered: For those with a heavier flow, this version of Fri Period underwear can hold three tampons worth making you feel secure and confident throughout the day (or night).
    • Your¬†perfect fit:¬†Made out of US-grown organic cotton, the high waist and full backside coverage will leave you feeling supported yet not constricted throughout the day.
    • Celebrating your body:¬†The printed gusset design celebrates our bodies and all of our healthy, normal functions. With Fri Period underwear, any staining blends with the gusset print to create your own unique design.¬†Because you, my friend, are a masterpiece!
    • Feel good about your choice:¬†Fri Period underwear is made in the USA, which means¬†hello¬†smaller carbon footprint,¬†bye-bye¬†lack of supply chain transparency and unfair working conditions. Fri Period underwear is made without using PFAS or other chemicals that can mess with your hormones.¬†Read more¬†about why you can feel good about wearing¬†Fri Period¬†underwear.


    New to period underwear? Click here for answers to all your questions.

    Customer Reviews

    Based on 6 reviews
    Megan Houseberg
    Happy With My Recent Purchase!

    I waited to go through two cycles prior to reviewing. I wore the medium-heavy flow full brief underwear on both a medium/light day, as well as on a heavy day. They are very comfortable and held everything in with no leaking. They are easy to care for and washed well. It is great to purchase a sustainable product that is also packaged in sustainable, compostable packaging! I will definitely be purchasing again!

    Lara GILL
    Super absorbent!

    I bought a pair of these for heavy flow days and they were just what I needed - especially for night time as they are so comfortable and no need to worry about leakage! I've used re-usable pads before, but these definitely work better in terms of comfort, duration of use, and bonus they mean no unsightly bulges in your knickers and they look great! They are easy to wash too.

    Novi J.
    Must buy!

    I absolutely love these period panties! I ordered a medium and they fit perfectly. I am normally a size 6 in pants. I ordered the medium/heavy flow and I was able to wear them overnight and throughout the day without any worry. They are very comfortable and keep you dry. I 100% recommend these. I will be purchasing more!

    Andrea J
    This is amazing!!!

    The product is awesome. I was holding off providing a review because I wanted to see how absorbent it was... turns out, I couldn't tell, because it's so incredibly absorbent!!!! They are miles comfier and cooler than modibody, which I had before.

    Bianca S
    Nice fit, excellent absorbency. Recommend.

    This was my first time trying period underwear and I'm a convert. I was reluctant to try before because I thought cleaning them would be a hassle but it's so easy. The actual panties are really soft and the padding doesn't feel at all bulky. Quality is good and I love the eco packaging. Will buy again.


    All your period underwear questions answered

    Period underwear is reusable underwear specifically designed to be worn during your period (but which can be worn throughout your menstrual cycle).

    The gusset is comprised of several layers that work together to wick, absorb and hold any liquid while keeping you feeling comfortable, fresh and secure on even your heaviest period day.

    As period underwear can be washed and reused many times, it's a more sustainable, eco-friendly, and cost-effective method for managing your period compared to single-use products like tampons and pads.

    Fri Period underwear can be used by everyone, and we cater for all ages, body shapes, and sizes.

    In fact, you don't even need to get a period to wear Fri Period underwear.

    They can also be worn to assist in light bladder leakage, for postpartum wear, and anyone who would benefit from having more absorbent underwear (for example, some athletes prefer to wear period underwear during their workouts).

    Our founders also find Fri Period underwear more comfortable and dry than regular underwear during those hot and sweaty summer days!

    The gusset of Fri Period underwear is comprised of several layers, which work together to wick away, then absorb and hold your period or discharge. This means that you feel fresh and dry, while Fri Period underwear does the work of more than two regular tampons (or more for our heavier absorbency models).

    For the heavier absorbency models of Fri Period underwear, we have doubled up on the internal absorbency for an exponential level of period-containment.

    Yes! You can rest assured that Fri Period underwear are safe to wear.

    The main body of Fri Period underwear is made out of US-grown organic cotton. In our opinion, it doesn't get any better than that.

    We've had to engineer some more high-tech, high-performing fabrics for our super clever gusset, but all our fabric is sourced from the US, and made without using PFAS, lead, dioxins, heavy metals, BPA, and phthalates. No gross stuff here!

    How long you can wear your Fri Period underwear depends on your body and flow, however here are some general guidelines.

    During the day, we suggest that Fri Period underwear can be worn for up to 8-10 hours, but if you notice any saturation, leakage or discomfort, then we recommend you change sooner.

    If you have purchased the lighter absorbency model, this may be a sign that the heavier absorbency model would work better for you. If you have a very heavy flow, you may need to change your Fri Period underwear more frequently. Also, keep an eye out for our super heavy flow model, launching soon!

    Fri Period underwear can be worn overnight.

    For most of us, our flow varies throughout our period, so you may find you can wear your Fri Period underwear for longer, or shift to the lighter absorbency model for the latter part of your cycle.

    We are all different, and so exactly how we use Fri Period underwear will vary from person to person. We recommend finding a system that works best for you. Contact us if you need further help with this - we'd love to hear from you!

    The main body of Fri Period underwear is made out of US-grown organic cotton. In our opinion, it doesn't get any better than that.

    We've had to engineer some more high-tech, high-performing fabrics for our super clever gusset, but all our fabric is sourced from the US, and made without using PFAS, lead, dioxins, heavy metals, BPA, and phthalates. No gross stuff here!

    This depends on how well you care for your underwear, and how often they're used. But Fri Period underwear are made in the USA. and undergo stringent quality checks, so you can expect them to last at least several years with proper care. We haven't cut corners on making these beauties, so they are robust!

    Fri Period underwear are very easy to wash and care for - that's why we designed them! Simply wash them in your washing machine at a low temperature, and only use detergent (organic cotton doesn't like extras like softener or bleach). Lay flat or hang on the line to dry.

    Please click here for detailed instructions on how to look after your Fri Period products, plus some pro tips to get the most out of them.

    Exercise: Yes! In fact, even if you're not on your period they're a fantastic option for exercise. The fabric is breathable and moisture-wicking, helping to keep you dry and comfortable during physical activity.

    Sleep: Yes! We LOVE to wear our Fri Period underwear while we sleep, and find it is the most comfortable solution for overnight period care.

    This depends on your individual menstrual cycle and flow; what you already have in your own period care kit; and how often you're able to run a wash in your washing machine. For many people, 3-5 pairs should be enough to last a period (although would require some washing during the period). If you're unsure about taking the leap to Fri Period underwear or don't know which Fri Period underwear would best suit your flow, we recommend starting with just one pair and seeing how you get on before buying more.


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